Stacking Winegard HD-6065P antennas

[Paul Pomes]

I'm looking for a source for a second Winegard HD-6065P antenna that I can stack with my existing one to increase the FM gain. At the moment I can pull in most Mt Wilson stations in San Diego, but only in mono. I realize an amplifier would likely do the job easier, but I think this would be a cool thing to do.

Cheers!
Paul Pomes, DVM

[Jeff Liebermann]

On Tue, 1 Jan 2013 14:07:45 -0800 (PST), Paul Pomes <pa...@pomes.org>
wrote:

>I'm looking for a source for a second Winegard HD-6065P antenna that I can stack with my existing one to increase the FM gain. At the moment I can pull in most Mt Wilson stations in San Diego, but only in mono. I realize an amplifier would likely do the job easier, but I think this would be a cool thing to do.
>
>Cheers!
>Paul Pomes, DVM

If you have lots of lossy coax cable and a typically insensitive
consumer grade receiver, an amplifier might give you 10dB of gain.
A second stacked antenna will give you exactly 3dB gain.

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Channel Jumper]

'Jeff Liebermann[_2_ Wrote:
> ;800247']On Tue, 1 Jan 2013 14:07:45 -0800 (PST), Paul Pomes
> pa...@pomes.org
> wrote:
> -

> I'm looking for a source for a second Winegard HD-6065P antenna that I
> can stack with my existing one to increase the FM gain. At the moment I
> can pull in most Mt Wilson stations in San Diego, but only in mono. I
> realize an amplifier would likely do the job easier, but I think this
> would be a cool thing to do.
>
> Cheers!

> Paul Pomes, DVM-

>
> If you have lots of lossy coax cable and a typically insensitive
> consumer grade receiver, an amplifier might give you 10dB of gain.
> A second stacked antenna will give you exactly 3dB gain.
>
> --
> Jeff Liebermann je...@cruzio.com
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558

I will agree with Jeff to a point, the pre amplifiers only job is to
compensate for line loss.
On 88 - 108 MHz there is not a lot of loss - hence there is not a lot to
be gained by using a preamplifier.
Winegard maintains a web site which can be accessed via internet - what
you need is a antenna with better rejection and more forward gain.

Because you did not post a physical address, there is no way for sure
for me to give you accurate information - because my crystal ball is
broken...

Go to FM Fool.com and post your address and you will get a beam heading
and distance to the transmitters.
It will also show a graph with what is between the transmit and the
receive antenna's...

FM works on the principal of capture effect - hence it will receive the
strongest signals and reject all others.
Your problem might be that you have another station on the same
frequency or close by that is stronger then the signal you desire...

The Winegard 7694 - 7698P antenna's are a very good source for better
reception. You might also want to incorporate a good antenna rotor...




--
Channel Jumper

[pelot...@gmail.com]

Oh, here:

Dear John,

Stacking 2 HD6065P antennas in the same direction for gain you would mount
them 72" apart vertically from boom to boom. The phasing line will be 52"
long each +/- 1/8" of each other in length. The phasing lines will feed a
CC-7870 coupler to combine the signals. Your single output is now you
signal.

Cordially,
Hans Rabong
Tech. Service Manager.
Winegard Company

[pelot...@gmail.com]

"only 3 db", but that's twice the signal. I have mine stacked 12 feet, but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I got mine just after they were discontinued in 2005/6. Had to email a number of suppliers until I found the second one. I bet there are some still in storage somewhere, email different places that sell Winegard, you may still find one.

John K9RZZ

[Ralph Mowery]

<pelot...@gmail.com> wrote in message
news:ee44b2e2-dcfb-4683...@googlegroups.com...

Dear John,

>Stacking 2 HD6065P antennas in the same direction for >gain you would mount
>them 72" apart vertically from boom to boom. The >phasing line will be 52"
>long each +/- 1/8" of each other in length. The phasing >lines will feed a
>CC-7870 coupler to combine the signals. Your single >output is now you
>signal.

>Cordially,
>Hans Rabong
>Tech. Service Manager.
>Winegard Company

Unless I am missing something, seems like a waste of antenna and money.

I looked for the coupler and found this:

"You have the CC-7870 hooked up properly. However this coupler is just like
a 2-way splitter hooked up in reverse; in that it will reduce the signal
from each antenna by about 30%. "

If it is just a 2 way splitter in reverse, there is usually a 3 db loss and
all you get with 2 antennas is a gain of 3 db, so you gain nothing over a
single antenna with this coupler.

To get close to 3 db of gain you need to have a combiner of near zero loss.
This is often done by using an odd number of wavelenghts of feedline of a
differant impedance and hooking them in parallel to keep the impedance the
same. I doubt it would work very well over the while FM band,but may for a
small portion of it.

I don't know how big the antenna is, but you would be beter off with a
single larger antenna, or possiably an amplifier.
Maybe an even beter feedline.



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[Jeff Liebermann]

On Sat, 4 Jan 2014 11:14:23 -0500, "Ralph Mowery"
<rmower...@earthlink.net> wrote:


>Unless I am missing something, seems like a waste of antenna and money.

Nope. Stacking antennas works.

Analysis of the HD-6066P antenna.
<http://www.ham-radio.com/k6sti/hd6065p.htm>

>"You have the CC-7870 hooked up properly. However this coupler is just like
>a 2-way splitter hooked up in reverse; in that it will reduce the signal
>from each antenna by about 30%. "

Since when do we measure signal levels in percent? Decibels would be
nice.
<http://www.solidsignal.com/pview.asp?p=cc7870&d=winegard-cc-7870-2-way-tv-antenna-joiner-coupler-(cc7870)>

>If it is just a 2 way splitter in reverse, there is usually a 3 db loss and
>all you get with 2 antennas is a gain of 3 db, so you gain nothing over a
>single antenna with this coupler.

Nope. Let's pretend for a moment that there's no loss in the
splitter/coupler. If you feed a signal into the common (output) port,
the RF power is split equally between the other two (input) ports for
a -3dB loss per port.

However, if you feed a signal into either ONE of the two (input)
ports, all of the signal will appear on the common (output) port.
That's because there's about 20dB of isolation between the two (input)
ports so that no RF is lost going out the other (input) port.

If you have the same signal (in phase) going into both the two (input)
ports, they add, producing a combined signal 3dB higher.

However, reality requires that the combiner has some loss. Usually,
that's about -0.5dB per (input) port for a total loss of 1dB. So,
instead of 3dB gain with the stacking arrangement, you will see about
2dB gain. The -0.5dB loss varies across the band and tends to be
higher at the extreme frequencies, and less in the middle.

>To get close to 3 db of gain you need to have a combiner of near zero loss.
>This is often done by using an odd number of wavelenghts of feedline of a
>differant impedance and hooking them in parallel to keep the impedance the
>same. I doubt it would work very well over the while FM band,but may for a
>small portion of it.

Yep. That's the problem. The splitter/combiner is a broadband
device, that will work over the entire TV band. 5-1000 MHz is common.
Not so if you remove the splitter/combiner and simply parallel the
phasing lines. That's a narrow band device that works over a narrow
frequency range determined by the length of the phasing lines. That's
not what you would want with a TV antenna.

However, the HD-6065P is a FM band only Yagi, which might work without
the splitter combiner, but as you mention, probably will not work over
the entire FM band.

>I don't know how big the antenna is, but you would be beter off with a
>single larger antenna, or possiably an amplifier.
>Maybe an even beter feedline.

If you use a Yagi antenna, you would need to approximately double the
length of the boom in order to obtain an additional 3dB of gain. The
boom on the HD-6065P is 128 inches long. I would hate to see a
similar antenna with a boom twice as long.

Yagi antennas also tend to be more narrow band than Gray Hoverman
antennas for TV use. For FM band only, gain is more important, so a
Yagi is probably best. For TV, I prefer a Gray Hoverman.

Incidentally, for TV, you can compare the characteristics between both
types for real antennas at:
<http://www.hdtvprimer.com/ANTENNAS/types.html>
<http://www.hdtvprimer.com/ANTENNAS/comparing.html>
<http://www.hdtvprimer.com/antennas/temporarypage.html>

[Ian Jackson]

In message <9oednWDYebX6rlXP...@earthlink.com>, Ralph
Mowery <rmower...@earthlink.net> writes

Strange as it may seem, if you use (for example) a TV 2-way '3dB'
splitter to combine two identical in-phase signals, you DON'T lose 3dB.
Apart from the unavoidable slight inherent losses of the two
transformers the circuit uses (a total of around 0.5dB at low VHF,
increasing to 1dB at high UHF), the splitter is lossless. Ignoring the
transformer loss, the 3dB loss occurs simply because the power at each
output port is half of that at the input. You haven't actually lost
anything.

If the splitter is now turned around to become a combiner, it doesn't
suddenly become more lossy. If you again ignore the transformer losses,
the two identical in-phase signals you feed into the 'output' ports are
added, and the result is a signal 3dB higher.

An interesting experiment would be to cascade two splitters - the first
used as a splitter, and the second used to combine the two split signals
(via identical lengths of coax). The loss (because of the transformers)
should be only 1dB (low VHF) to around 2dB (high UHF), and not 7 to 8dB.
--
Ian

[Ralph Mowery]

"Jeff Liebermann" <je...@cruzio.com> wrote in message
news:hurgc99p4tp5t5l1b...@4ax.com...

> On Sat, 4 Jan 2014 11:14:23 -0500, "Ralph Mowery"
> <rmower...@earthlink.net> wrote:
>
>
>>Unless I am missing something, seems like a waste of antenna and money.
>
> Nope. Stacking antennas works.
>
> Analysis of the HD-6066P antenna.
> <http://www.ham-radio.com/k6sti/hd6065p.htm>
>
>>"You have the CC-7870 hooked up properly. However this coupler is just
>>like
>>a 2-way splitter hooked up in reverse; in that it will reduce the signal
>>from each antenna by about 30%. "
>
> Since when do we measure signal levels in percent? Decibels would be
> nice.
> <http://www.solidsignal.com/pview.asp?p=cc7870&d=winegard-cc-7870-2-way-tv-antenna-joiner-coupler-(cc7870)>
>

I agree that stacking antennas works, the problem I have is the type of
combiner that is used.

The 30% was from another web site and I assume it was from someone at the
Winegard factory. Not sure why he would say 30% instead of db. Even so 30
% is nowhere near the 3.5 db listed in the ad. From the url you gave, the
spec is for 3.5 db which is around what I would think it could be if simple
resistors were used.

That combiner seems to be made not for stacking antennas for more gain, but
to combine several antennas either pointed at differant directions or so a
single feedline could be used for a TV and FM antenna or where you hae
seperate antennas on the same mast for UHF and VHF.

As the specs is for a 3.5 db loss, I assume that is if you hook up two
antennas to it, the antennas will have a gain of 3 db at the most, then you
go to the combiner and loose 3.5 db for an overall loss of .5 db.

That is where I don't see stacking two antennas and using that combiner for
more signal strength.


I do agree that to get 3 db of gain from the antenna it would need to be
about twice as long. I did not look up to antenna to see that it was about
10 feet long already. A 20 foot long antenna would be large, but so would
two antennas 10 feet long and seperated by around 5 feet.

Maybe not too bad as I have several antennas on booms that are close to 15
feet long stacked about 5 feet apart. Not the best, but it was what I could
do for what I had to work with. You can see them on my QRZ.com page under
KU4PT.

[Ralph Mowery]

"Ian Jackson" <ianREMOVET...@g3ohx.demon.co.uk> wrote in message

> Strange as it may seem, if you use (for example) a TV 2-way '3dB' splitter
> to combine two identical in-phase signals, you DON'T lose 3dB. Apart from
> the unavoidable slight inherent losses of the two transformers the circuit
> uses (a total of around 0.5dB at low VHF, increasing to 1dB at high UHF),
> the splitter is lossless. Ignoring the transformer loss, the 3dB loss
> occurs simply because the power at each output port is half of that at the
> input. You haven't actually lost anything.
>
> If the splitter is now turned around to become a combiner, it doesn't
> suddenly become more lossy. If you again ignore the transformer losses,
> the two identical in-phase signals you feed into the 'output' ports are
> added, and the result is a signal 3dB higher.
>

Jeff found a url with the specs for the combiner.
<http://www.solidsignal.com/pview.asp?p=cc7870&d=winegard-cc-7870-2-way-tv-antenna-joiner-coupler-(cc7870)>

It says 3.5 db of loss. I assume they use the simple resistor network
instead of transformers. If so, then the net results not counting feedline
loss would be a minus .5 db.

That combiner does not seem to be made to add signals from idinitical
antennas for more gain, but just to let you use one feedling for several
differant antennas such as putting a FM antenna up and a TV antenna up, or a
seperate UHF and VHF antenna up and using one feedline to the receiver.

I have one for designed for my ham transceivers,and have measured less
than .5 db of loss, but that is for differant frequency ranges and not to
combind two antennas on the same band.


Even if he does get the maximum of 3 db of gain, will that acutally get him
anywhere ? Will that be enough gain for the FM broadcast band to be
noticiable ?

[Ian Jackson]

In message <FrCdnWycmtwoDVXP...@earthlink.com>, Ralph
Mowery <rmower...@earthlink.net> writes
>

>"Ian Jackson" <ianREMOVET...@g3ohx.demon.co.uk> wrote in message
>
>> Strange as it may seem, if you use (for example) a TV 2-way '3dB' splitter
>> to combine two identical in-phase signals, you DON'T lose 3dB. Apart from
>> the unavoidable slight inherent losses of the two transformers the circuit
>> uses (a total of around 0.5dB at low VHF, increasing to 1dB at high UHF),
>> the splitter is lossless. Ignoring the transformer loss, the 3dB loss
>> occurs simply because the power at each output port is half of that at the
>> input. You haven't actually lost anything.
>>
>> If the splitter is now turned around to become a combiner, it doesn't
>> suddenly become more lossy. If you again ignore the transformer losses,
>> the two identical in-phase signals you feed into the 'output' ports are
>> added, and the result is a signal 3dB higher.
>>
>
>Jeff found a url with the specs for the combiner.
><http://www.solidsignal.com/pview.asp?p=cc7870&d=winegard-cc-7870-2-way-
>tv-antenna-joiner-coupler-(cc7870)>
>

$18.99? They're having a laff! $5 max.

>It says 3.5 db of loss. I assume they use the simple resistor network
>instead of transformers. If so, then the net results not counting feedline
>loss would be a minus .5 db.
>

A typical TV 2-way equal splitter has 3dB splitting loss (because it
splits the signal in two), plus a little loss in the two ferrite-cored
RF transformers inside. The spec is usually something like 3.5dB at
50MHz, increasing to 4 or 4.5dB at 900MHz.

A resistive 2-way star or delta splitter/combiner has a loss of 6dB (3
due to the splitting, and 3 in the resistors), However, whereas the 3dB
transformer splitter theoretically has infinite isolation between the
outputs (when the input is terminated) - and in practice it is 25 to
40dB - the 6dB resistive splitter/combiner has only 6dB (essentially,
all three ports are interchangeable).

>That combiner does not seem to be made to add signals from idinitical
>antennas for more gain, but just to let you use one feedling for several
>differant antennas such as putting a FM antenna up and a TV antenna up, or a
>seperate UHF and VHF antenna up and using one feedline to the receiver.
>

It is extremely bad practice to use a wideband combiner to connect two
antennas pointing in different directions. For analogue signals, that's
a sure recipe for multipath and ghosting - and it can't be good for
digitals either. The combiner needs to be filtered (eg a diplexer), so
that one antenna provides signals (on the appropriate frequencies) from
one direction, and the other antenna provides signals (on the
appropriate frequencies) from the other direction.

>I have one for designed for my ham transceivers,and have measured less
>than .5 db of loss, but that is for differant frequency ranges and not to
>combind two antennas on the same band.
>

That sounds like a diplexer (frequency selective), and not a wideband
splitter/combiner. These can indeed be low loss, as they consist of
frequency-selective (or lowpass-highpass) filters connected to a common
port, and there is no need for wideband combining/splitting.

>
>Even if he does get the maximum of 3 db of gain, will that acutally get him
>anywhere ? Will that be enough gain for the FM broadcast band to be
>noticiable ?

Well, every little helps!
>
>
--
Ian

[Ralph Mowery]

"Ian Jackson" <ianREMOVET...@g3ohx.demon.co.uk> wrote in message >

Strange as it may seem, if you use (for example) a TV 2-way '3dB'
> splitter to combine two identical in-phase signals, you DON'T lose 3dB.
> Apart from the unavoidable slight inherent losses of the two transformers
> the circuit uses (a total of around 0.5dB at low VHF, increasing to 1dB at
> high UHF), the splitter is lossless. Ignoring the transformer loss, the
> 3dB loss occurs simply because the power at each output port is half of
> that at the input. You haven't actually lost anything.
>
> If the splitter is now turned around to become a combiner, it doesn't
> suddenly become more lossy. If you again ignore the transformer losses,
> the two identical in-phase signals you feed into the 'output' ports are
> added, and the result is a signal 3dB higher.
>
>

I don't have a TV splitter/combiner to play with. I do have a MiniCircuits
combiner I have been playing with.
http://www.minicircuits.com/pdfs/ZFSC-2-2.pdf

I am not sure what is in the combiner but it must be transformers of some
type as the resistance of the ports are near zero ohms.

Their specs is for a 3 db loss and then an aditional loss of about .2 to
1.2 depending on the frequecy. Are you sure that is not the case where you
are saying you do not loose the 3 db ? That is the ratings is for the extra
.5 or so not counting the already 3 db of loss.

Maybe you can tell me if I am playing with the wrong type of combiner.. Here
are some results of my tests. using a HP 8924C service monitor and another
signal generator.


With one input port of the combiner having a signal and the other port
terminated with a 50 ohm load (the nominal impedance of all devices) there
is a 3 db loss (small values not being included) not the low values you
mention to the output port. When I hook up the other signal generator, I
get from almost a total of 0 db to 6 db of loss. I asume the spectrum
analizer going from 0 to 6 db is the phasing of the two generators.

[Jerry Stuckle]

On 1/4/2014 5:40 PM, Ralph Mowery wrote:
>

<snip>

> As the specs is for a 3.5 db loss, I assume that is if you hook up two
> antennas to it, the antennas will have a gain of 3 db at the most, then you
> go to the combiner and loose 3.5 db for an overall loss of .5 db.
>
> That is where I don't see stacking two antennas and using that combiner for
> more signal strength.
>

Jeff is correct. Your error is believing the combiner has 3.5db loss.

When splitting a signal, you do have about a 3.5db loss per output,
because the signal is halved plus a bit of additional loss. However,
when combining the signals, the signal is NOT halved, so you don't have
the 3db loss there. You only have about 0.5db loss (more or less,
depending on the quality of the combiner and other factors).

Let's take an example. Since a combiner is just a splitter turned
around, we'll start with the splitter end.

Let's feed 2mw to the input of the splitter. This means each output
gets 1mw (3db loss) (we could use voltage also, but since power is
E^2/R, it's not so straightforward).

So now each leg has 1mw on it.

Now let's turn the splitter around and make it a combiner and feed two
signals, 1mw ea., same frequency, to the inputs to the combiner. Since
this is a totally passive device, the effects are reversible. If the
signals are 180 degrees out of phase, of course the output is 0.
However, if the two signals are in phase with each other, the putout is 2mw.

Note there is no 3db loss in the combiner. But of course this assumed a
"perfect" combiner, with no losses. In reality, the combiner will have
a bit of loss (typically 0.5db as noted above), so the output from the
splitter will be slightly less than 1mw and the output from the combiner
will be slightly less than 2mw.

Does this help clarify things?

And yes, phasing harnesses work the same way. The can be either
splitters or combiners, depending on how they are used. The advantage
is they have less loss; the disadvantage, as noted, is they have a much
narrower effective bandwidth.

--
==================
Remove the "x" from my email address
Jerry, AI0K
jstu...@attglobal.net
==================

[Ralph Mowery]

"Jerry Stuckle" <jstu...@attglobal.net> wrote in message
news:laadjr$ns3$1...@dont-email.me...

What I am having trouble with is the 'perfect' combiner.
The one by Wineguard specs 3.5 db loss and the MiniCircuits I have specs at
3 db plus slightly more depending on frequency. I had forgotten that I
built one years ago out of the ARRL Handbook. They give it a spec of 6 db
of loss per port. The one I built has that not counting minor errors and
loss. Just checked it out.

My problem is where are you going to find a combiner for a broad frequency
that does not have any large (say over 1 db ) of loss ? Are the ones for
the TV frequencies built differant ?

For the splitters, I see the 3 db because the signal is going to two places
(3 db equals half power as we all know). But then the problem I am having
is the extra 3 db that is lossed in the combiner instead of just half of a
db or so.

Has anyone actually put one on accurate test equipment to see about the loss
like I have been trying to do ?

I understand phasing harnesses for antennas. They are almost loseless. Only
a few feet of coax worth. I have used them on antennas before. They are
not usually very broad banded unless the antennas are broad banded and made
so the impedance is not the nominal 50 ohms. That is for comercial 4 or 8
dipole arays for VHF/UHF. Lots of 'tricks' used to do that.

[Jerry Stuckle]

A perfect combiner (like anything else "perfect") doesn't exist. But it
is a very common (and handy) way of specifying how things work. It's
used all over the place in EE degree programs, for instance.

So you start with the perfect item, then add losses, phase shifts, etc.
as they occur to get a "real" part.

> My problem is where are you going to find a combiner for a broad frequency
> that does not have any large (say over 1 db ) of loss ? Are the ones for
> the TV frequencies built differant ?
>

There are good combiners and bad combiners. The commercial grade ones
we use typically have < 1db loss from 50Mhz to 2Ghz. Note that these
are basically splitters which are reversed to form combiners, when
necessary.

> For the splitters, I see the 3 db because the signal is going to two places
> (3 db equals half power as we all know). But then the problem I am having
> is the extra 3 db that is lossed in the combiner instead of just half of a
> db or so.
>

In a good quality combiner, there is no extra 3db of loss.

> Has anyone actually put one on accurate test equipment to see about the loss
> like I have been trying to do ?
>

I haven't actually measured it myself, but I do use commercial grade
splitters/combiners (not as much any more because a lot of video has
gone digital). Typical loss as a combiner is around 0.5 - 0.7 db from
50Mhz to 2Ghz.

But you also won't find these at Radio Shack or Best Buy.

And there are testing labs out there who do test these things; if any of
the ratings were off, the manufacture would quickly lose credibility in
commercial circles.

> I understand phasing harnesses for antennas. They are almost loseless. Only
> a few feet of coax worth. I have used them on antennas before. They are
> not usually very broad banded unless the antennas are broad banded and made
> so the impedance is not the nominal 50 ohms. That is for comercial 4 or 8
> dipole arays for VHF/UHF. Lots of 'tricks' used to do that.
>

Phasing harnesses are just another form of splitter/combiner. One way
they combine; turn them around and they split. That's why they work for
both transmitting and receiving.

>
>
>
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[Jeff Liebermann]

On Sat, 4 Jan 2014 17:40:20 -0500, "Ralph Mowery"
<rmower...@earthlink.net> wrote:

>I agree that stacking antennas works, the problem I have is the type of
>combiner that is used.

Well, one could always use an active combiner. For just the FM band,
that's quite easy.

>The 30% was from another web site and I assume it was from someone at the
>Winegard factory. Not sure why he would say 30% instead of db.

This may help explain the problem:
<http://www.journalistunits.com>
It doesn't include most electronic units of measure, but I think you
see the problem.

>Even so 30
>% is nowhere near the 3.5 db listed in the ad. From the url you gave, the
>spec is for 3.5 db which is around what I would think it could be if simple
>resistors were used.

Nope. A resistive combiner/splitter is -6dB.
<http://www.microwaves101.com/encyclopedia/resistive_splitters.cfm>
"Resistive power dividers are easy to understand, can be made
very compact, and are naturally wideband, working down to
zero frequency (DC). Their down side is that a two-way resistive
splitter suffers 10xlog(1/2) or 3.0103 dB of real resistive loss,
as opposed to a lossless splitter like a hybrid. Accounting for
3.0103 dB real loss and 3.0103 dB power split, the net power
transfer loss you will observe from input to one of two outputs
is 6.0206 dB for a two-way resistive splitter, so they are often
called 6 dB splitters. Dig?"

>That combiner seems to be made not for stacking antennas for more gain, but
>to combine several antennas either pointed at differant directions or so a
>single feedline could be used for a TV and FM antenna or where you hae
>seperate antennas on the same mast for UHF and VHF.

When one combines two different band antennas, the usual method is a
diplexer. Since the receiver only sees one antenna on each band, the
impedance is constant. A low pass filter can also be made very low
loss if you don't care much about rolloff and ripple. However, if
we're down to the point where small fractions of a dB produce a
noticeable difference, I suspect that additional gain (tower mounted
pre-amp) or less loss (better coax cable) will be more important.
Something like this:
<http://www.solidsignal.com/pview.asp?p=uvsj>
0.5 dB insertion loss. Oh well.

>As the specs is for a 3.5 db loss, I assume that is if you hook up two
>antennas to it, the antennas will have a gain of 3 db at the most, then you
>go to the combiner and loose 3.5 db for an overall loss of .5 db.

Please re-read what I wrote. From each of the (input) ports to the
receiver port (output), there is only 0.5dB of loss. If two antennas
provide an additional 3dB of gain, and each port gobbles 0.5dB, then
the combined gain is 2dB.

>That is where I don't see stacking two antennas and using that combiner for
>more signal strength.

Would you rather make the yagi twice as long? Once we get to very
large antennas, 3dB of additional gain can easily become a mechanical
challenge.

>I do agree that to get 3 db of gain from the antenna it would need to be
>about twice as long. I did not look up to antenna to see that it was about
>10 feet long already. A 20 foot long antenna would be large, but so would
>two antennas 10 feet long and seperated by around 5 feet.

Note that FM broadcast stations with directional antennas use various
vertically mounted antennas, not Yagis. They're interested in
survivability as well as gain and pattern. A 20ft long antenna is
possible, but I don't think anyone wants to climb the tower and drop
the antenna to fix a broken element. That's much easier with a side
mounted barbeque grill type antenna, stacked dipoles, crossed dipoles,
horizontal loops, etc.

>Maybe not too bad as I have several antennas on booms that are close to 15
>feet long stacked about 5 feet apart. Not the best, but it was what I could
>do for what I had to work with. You can see them on my QRZ.com page under
>KU4PT.

You probably don't have overweight birds sitting on your yagi
elements. Yes, it can be made to work but it's so much easier and
neater to do it with a combiner.

[Jeff Liebermann]

On Sat, 4 Jan 2014 21:23:14 -0500, "Ralph Mowery"
<rmower...@earthlink.net> wrote:

>What I am having trouble with is the 'perfect' combiner.

I feel your pain. Many years ago, I made a similar mistake on the NEC
antenna modeling mailing list. I then processed to make a total fool
of myself and had to be corrected by the experts. Even so, I still
didn't believe it so I built a Wilkinson combiner and bench tested it
for loss. I still have the combiner somewhere as a reminder of my
mistake.

Incidentally, a Wilkinson combiner might be a tolerable solution for
combining two FM antenna. The loss is much less than a bifilar wound
toroid. I'm not sure if it will work over the entire FM band. I can
grind the numbers if anyone is interested.

>My problem is where are you going to find a combiner for a broad frequency
>that does not have any large (say over 1 db ) of loss ? Are the ones for
>the TV frequencies built differant ?

There's only so much you can do with passive only designs. The next
step up is an active combiner:
<http://www.rldrake.com/product-ac1686.php>
0-3dB gain per port. 54 to 860 MHz.

>Has anyone actually put one on accurate test equipment to see about the loss
>like I have been trying to do ?

Yep. I have. There's very little loss between the combiner input
ports and the "sum" port. However, in the other direction, there's a
bit over 3dB loss due to the power splitting. See the specs on the
MCL splitter/combiner that you have and try it with a service monitor
or generator. Since it works down to 10 MHz, you might be able to do
the test with a function generator, a few dummy loads, some T
connectors, and an oscilloscope.

>I understand phasing harnesses for antennas. They are almost loseless. Only
>a few feet of coax worth. I have used them on antennas before. They are
>not usually very broad banded unless the antennas are broad banded and made
>so the impedance is not the nominal 50 ohms. That is for comercial 4 or 8
>dipole arays for VHF/UHF. Lots of 'tricks' used to do that.

It's low, but the phasing harness loss for stacked vertical dipoles is
not zero. I've never calculated or measured it, but this might help:
<http://www.kg4jjh.com/pdf/2-Meter%20Vertical%20Dipole%20Array.pdf>
"The phasing harness loss at 150 MHz is calculated to be 0.67 dB."
Scaled for 100 Mhz, I would guess about 0.5 dB. Might as well use a
combiner/splitter.

[Ralph Mowery]

"Jeff Liebermann" <je...@cruzio.com> wrote in message

news:f8ihc99m90apbs4u7...@4ax.com...

I understand the idea of using 'perfect' items in electronics, then going
for more exect calculations if needed. As most electronic items are often a
5 to 10 percent variation anyway. Often you get a close calculation and
build it and trim for the desired results. I did take 2 year course in
electronics engineering about 40 years ago for an associates degree, so know
about perfect vers real components.

The Wilkinson combiner is possiable for relative narrow frequencies. Not
sure if building one out of descrete components or full size transmission
lines would be broad enough for the whole FM band either. Wild guess it
would be about the same if just two pieces of transmission line of the
correct impedance and length were used.

Isn't the Wilkinson combiner just two pieces of transmission line (or
simulated with components) with a resistor across two of the ports to
absorbe the diffeance if the loads/sources are not ballanced ? I know what
they are and have seen equipment with them in it,but never did much of a
study on it.


As the subject is combining, I have not looked into the losses of splitting,
but it would be 6 db for the simple resistor designs not counting the minor
losses. That would be 3 db for the ports and 3 db lost in the resistors.

To combind signals you would get the loss of the resistors of 3 db and a
fraction of other loss.

I am using a HP 8924C for a test set. It has just about everything you can
think of for a service monitor. Calibrated from 30 to 1000 MHz but usuable
uncalibrated to about a half of a mhz.
http://www.amtronix.com/hp8924c60.htm

As mentioned the only combiner I have is a MiniCircuits and they spec it at
3 db plus small losses depending on the frequency. That is what I am
measuring.

The diplexer/combiner will have very low loss. I have checked out 2 of them
in the past just to see and the losses were about half a db or so. However
that is for frequencies seperated by a very large percentage. Usually one
port is a low pass and the other is a high pass filter. Not suited for
signals on the same frequency as the origional poster wanted to do.

Yes, phasing harnesses on antennas are not totally loseless, but will be
mainly whatever the loss of the coax is between the elements.

If were the origional poster and there were not too many transmitters near
me, I would try a good preamp first. Mast mounted if possiable as it is for
receive only.

[Ralph Mowery]

"Jerry Stuckle" <jstu...@attglobal.net> wrote in message

news:laagja$5d6$1...@dont-email.me...

> A perfect combiner (like anything else "perfect") doesn't exist. But it
> is a very common (and handy) way of specifying how things work. It's used
> all over the place in EE degree programs, for instance.
>
> So you start with the perfect item, then add losses, phase shifts, etc. as
> they occur to get a "real" part.
>
>>

I am awear of that 'perfect' vers 'real world'. Took a 2 year asociate
degree in electronics engineering about 40 years ago. Most things are
calculated close and then trimmed to take care of the usual 5 to 10 percent
differance in components.

That is why I was not worried about anything under a DB, but just the parts
close to 3 db.

[Ian Jackson]

In message <sLqdnXMR29CHLlXP...@earthlink.com>, Ralph
Mowery <rmower...@earthlink.net> writes
>

>"Ian Jackson" <ianREMOVET...@g3ohx.demon.co.uk> wrote in message >
>Strange as it may seem, if you use (for example) a TV 2-way '3dB'
>> splitter to combine two identical in-phase signals, you DON'T lose 3dB.
>> Apart from the unavoidable slight inherent losses of the two transformers
>> the circuit uses (a total of around 0.5dB at low VHF, increasing to 1dB at
>> high UHF), the splitter is lossless. Ignoring the transformer loss, the
>> 3dB loss occurs simply because the power at each output port is half of
>> that at the input. You haven't actually lost anything.
>>
>> If the splitter is now turned around to become a combiner, it doesn't
>> suddenly become more lossy. If you again ignore the transformer losses,
>> the two identical in-phase signals you feed into the 'output' ports are
>> added, and the result is a signal 3dB higher.
>>
>>
>
>I don't have a TV splitter/combiner to play with. I do have a MiniCircuits
>combiner I have been playing with.
>http://www.minicircuits.com/pdfs/ZFSC-2-2.pdf
>

The spec says "• low insertion loss, 0.4 dB typ."
This is the real loss - the loss that will make the splitter get warm
when you feed a signal into it.

>I am not sure what is in the combiner but it must be transformers of some
>type as the resistance of the ports are near zero ohms.

The usual basic circuit is:
Input port to ground - a 2:1 impedance ratio step-down ferrite-cored
autotransformer T1 to ground.
T1 tap is connected to the centre tap of a second 1:1 ratio
ferrite-cored autotransformer T2.
Each end of T2 of connected to each output port.
A 100* ohm resistor R is connected between the ends of T2 (ie between
the output ports).
*R is 2 x Zo, so for a 75 ohm system, it will be 150 ohms. Note the
purpose of T2 and R is to provide isolation between the outputs (for
signals coming back into the output ports).

>
>Their specs is for a 3 db loss and then an aditional loss of about .2 to
>1.2 depending on the frequecy. Are you sure that is not the case where you
>are saying you do not loose the 3 db ? That is the ratings is for the extra
>.5 or so not counting the already 3 db of loss.
>

For forward-going signals, T2 and R play no part in the operation of
the circuit. The signal current from T1 tap enters T2 at its centre tap,
splits, and flows outwards in opposite directions to the ends of T2. The
magnetic flux created by the currents cancels out, so T2 presents no
impedance whatsoever. In effect, it isn't there, and the two outputs are
connected in parallel. The impedance presented to the centre tap of T1
is therefore 25 ohms, which is exactly what T1 is there for - to match
the 50 ohm input to 25 ohms of the two (effectively) parallel outputs.

So you see that apart from the unavoidable losses in the transformers
and in the copper wire, there are no losses in this circuit. However,
because the power emerging from each output is half the power of the
input, the loss measures 3dB (plus a bit). If you can devise a passive
2-way equal splitter with less than 3dB loss, you will make a fortune!

>Maybe you can tell me if I am playing with the wrong type of combiner.. Here
>are some results of my tests. using a HP 8924C service monitor and another
>signal generator.
>

Theoretically, this type of circuit has no loss (whether used as a
splitter of an in-phase combiner). It's only the 'extra' losses that
will give you trouble. The same is true of any other type of combiner,
so which one you use may depend on which will have the least extra loss.
If you don't need high (or any) isolation between the 'output' ports
('input' if a combiner), you might do better with one of the
transmission line alternatives.

>
>With one input port of the combiner having a signal and the other port
>terminated with a 50 ohm load (the nominal impedance of all devices) there
>is a 3 db loss (small values not being included) not the low values you
>mention to the output port. When I hook up the other signal generator, I
>get from almost a total of 0 db to 6 db of loss. I asume the spectrum
>analizer going from 0 to 6 db is the phasing of the two generators.
>

Not quite sure what you're doing here. However, for this circuit to act
as a lossless combiner, it relies on there being no voltage across the
resistor R. This means that the two input signals must in phase and of
equal amplitude.

Typical measurements for this sort of device would be (with all three
ports correctly terminated):
In to Out: 3.5dB
Out to Out: 30dB
With one Out unterminated (o/c or s/c):
In to Out: 3.5 to 4dB
With In unterminated (o/c or s/c):
Out to Out: 7dB
--
Ian

[Ralph Mowery]

"Ian Jackson" <ianREMOVET...@g3ohx.demon.co.uk> > The usual basic

circuit is:
> Input port to ground - a 2:1 impedance ratio step-down ferrite-cored
> autotransformer T1 to ground.
> T1 tap is connected to the centre tap of a second 1:1 ratio ferrite-cored
> autotransformer T2.
> Each end of T2 of connected to each output port.
> A 100* ohm resistor R is connected between the ends of T2 (ie between the
> output ports).
> *R is 2 x Zo, so for a 75 ohm system, it will be 150 ohms. Note the
> purpose of T2 and R is to provide isolation between the outputs (for
> signals coming back into the output ports).

Now we are getting somewhere. The circuit you describe is differant from
any that I have seen in my very short search for combiners. With nothing
but transformers in the circuit I can see where the losses would only be
part of a DB or so. Much differant than the combiners that I saw using
either resistors or combinations of resistors and a single core
'transformer'.

[Ian Jackson]

In message <peqdnfZJ8_XN61TP...@earthlink.com>, Ralph
Mowery <rmower...@earthlink.net> writes
>

>"Ian Jackson" <ianREMOVET...@g3ohx.demon.co.uk> > The usual basic
>circuit is:
>> Input port to ground - a 2:1 impedance ratio step-down ferrite-cored
>> autotransformer T1 to ground.
>> T1 tap is connected to the centre tap of a second 1:1 ratio ferrite-cored
>> autotransformer T2.
>> Each end of T2 of connected to each output port.
>> A 100* ohm resistor R is connected between the ends of T2 (ie between the
>> output ports).
>> *R is 2 x Zo, so for a 75 ohm system, it will be 150 ohms. Note the
>> purpose of T2 and R is to provide isolation between the outputs (for
>> signals coming back into the output ports).
>
>Now we are getting somewhere. The circuit you describe is differant from
>any that I have seen in my very short search for combiners. With nothing
>but transformers in the circuit I can see where the losses would only be
>part of a DB or so. Much differant than the combiners that I saw using
>either resistors or combinations of resistors and a single core
>'transformer'.
>

This circuit is used in 1001 makes of wideband FM/TV splitters
(typically 5 to 900+MHz) and even in satellite IF splitters up to
2100MHz. It is also widely used for combining signals on different
frequencies (where the loss is indeed 3-plus-some dB). However, while it
CAN be used for combining co-phased antennas, it's more usual to use
transmission lines (as have been described). Note that the small
ferrite-cored transformers are completely suitable for putting any real
RF power into, but transmission lines don't have this problem.
--
Ian

[gregz]

Twice the signal means twice the voltage, for me.

Greg

[Jerry Stuckle]

Twice the voltage is a 6 db gain. Twice the power is a 3db gain.

--
==================
Remove the "x" from my email address

Jerry Stuckle
JDS Computer Training Corp.
jstu...@attglobal.net
==================

[Jeff Liebermann]

On Mon, 6 Jan 2014 06:28:11 +0000 (UTC), gregz <ze...@comcast.net>
wrote:

Nope. Power is by the square of the voltage:
P = V^2 / R
If you double the voltage, you get 4 times the power.
A 1.414 times increase in voltage will produce twice the power.

I tried to convert the antenna model of the HD-6066P antenna from the
AO .ant format to .nec using 4NEC2 and failed. The plan was to model
the stacked arrangement and see what happens:
<http://www.ham-radio.com/k6sti/hd6065p.htm>
The .ant file imported without error, the wire tables and images look
correct, but the pattern is more like a point source than a gain
antenna. I'll look at it later to see where I screwed up, but it
would be nice if someone would look at the problem.

[gregz]

Jerry Stuckle <jstu...@attglobal.net> wrote:
> On 1/6/2014 1:28 AM, gregz wrote:
>> <pelot...@gmail.com> wrote:
>>> "only 3 db", but that's twice the signal. I have mine stacked 12 feet,
>>> but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I
>>> got mine just after they were discontinued in 2005/6. Had to email a
>>> number of suppliers until I found the second one. I bet there are some
>>> still in storage somewhere, email different places that sell Winegard,
>>> you may still find one.
>>>
>>> John K9RZZ
>>
>> Twice the signal means twice the voltage, for me.
>>
>> Greg
>>
>
> Twice the voltage is a 6 db gain. Twice the power is a 3db gain.

Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal.

Greg

[Jerry Stuckle]

No, 2 microvolts would be four times the signal. Remember that power
equals the voltage SQUARED divided by resistance. When you double the
voltage, you also double the amperage (assuming resistance stays the same).

--
==================
Remove the "x" from my email address

Jerry, AI0K
jstu...@attglobal.net
==================

[Jeff Liebermann]

On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz <ze...@comcast.net>
wrote:

Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal
voltage but only 1.414 times the signal power. That's why we have
units of measure to avoid such ambiguities. Just to be difficult,
working with antennas, the "signal" is the field strength measured in
dBuV/M. If you define what you're measuring and specify your units of
measure, you wouldn't be having such problems.

[Jerry Stuckle]

On 1/6/2014 11:04 PM, Jeff Liebermann wrote:
> On Tue, 7 Jan 2014 03:19:54 +0000 (UTC), gregz <ze...@comcast.net>
> wrote:
>
>> Jerry Stuckle <jstu...@attglobal.net> wrote:
>>> On 1/6/2014 1:28 AM, gregz wrote:
>>>> <pelot...@gmail.com> wrote:
>>>>> "only 3 db", but that's twice the signal. I have mine stacked 12 feet,
>>>>> but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I
>>>>> got mine just after they were discontinued in 2005/6. Had to email a
>>>>> number of suppliers until I found the second one. I bet there are some
>>>>> still in storage somewhere, email different places that sell Winegard,
>>>>> you may still find one.
>>>>> John K9RZZ
>
>>>> Twice the signal means twice the voltage, for me.
>>>> Greg
>
>>> Twice the voltage is a 6 db gain. Twice the power is a 3db gain.
>
>> Exactly. If I got 1 microvolt, 2 microvolts will be twice the signal.
>> Greg
>
> Sorta. If you got 1 microvolt, 2 microvolts will be twice the signal
> voltage but only 1.414 times the signal power. That's why we have
> units of measure to avoid such ambiguities. Just to be difficult,
> working with antennas, the "signal" is the field strength measured in
> dBuV/M. If you define what you're measuring and specify your units of
> measure, you wouldn't be having such problems.
>

You've got it backwards, Jeff. Twice the voltage is 4 times the power.

1.414 times the voltage would be twice the power.

--
==================
Remove the "x" from my email address

Jerry, AI0K
jstu...@attglobal.net
==================

[Jeff Liebermann]

On Mon, 06 Jan 2014 23:23:56 -0500, Jerry Stuckle

Very embarrassing. Temporary loss of IQ from working on my broken car
with a cold or flu this afternoon. It should be:

If you got 1 microvolt, 2 microvolts will be twice the signal

voltage but 4 times the signal power.

Thanks for the correction (grumble)... Maybe if I go to sleep early,
when I wake up tomorrow, this didn't happen.

[gregz]

I have not really been specifying units. I was just going over the
situation in my mind, and I straightened out in rf terms.

I got this going out terminology. IF, in audio, I got two speakers
transmitting equal energy, with two amps or channels, and I receive that
totally in phase, I got twice the signal or 6 dB power increase. I've
measured it. It's true. Same thing would happen with two antennas with two
transmitters. Two antennas, one transmitter, with one splitter would only
give 3 dB power increase at the receiver. I'm just thinking out loud. I had
to ease my mind. I think I'm ok now. Almost bedtime.

Greg

[gregz]

Tomorrow I will think the reverse of the antenna reception combining. It
does not work for me right now.

Greg

[Jerry Stuckle]

No, two in-phase speakers provide 3db increase, not 6db.

If you could double the signal and get 4x the power you could make
gazillions! Of course, you'd be creating energy out of nothing, but who
cares about the laws of physics? :)

[Ian Jackson]

In message <lagoq1$5s3$1...@dont-email.me>, Jerry Stuckle
<jstu...@attglobal.net> writes

Two identical receiving antennas would provide twice the signal voltage
if their RF outputs were connected in series.

One way of doing this would be for coax feed from each antenna to be
connected to the primary of a 1:1 RF transformer, and the secondaries of
the two transformers were connected in series. So if each antenna
delivered 1V from a resistive source impedance (R) of 1 ohm into a
matched resistive load of 1 ohm, the two secondaries in series would
provide 2V. However, the output impedance of the two secondaries would
be twice that of each antenna, ie 2R. To preserve matching, the load
would also have to be 2R.

However, the snag is.....
The matched power from each antenna is 1V squared divided by 1 ohm
(=1W), but the matched power from the combined antennas is 2V squared
divided by 2 ohms (=2W) - which is an increase of 3dB (and not 6dB).

Of course, if the receiver input was not matched, and its impedance was
much higher than R or 2R, it might be possible to benefit from adding
the two antenna signals in this way. Has anybody tried this?
--
Ian

[boomer]

>>
>> No, two in-phase speakers provide 3db increase, not 6db.
>>
>> If you could double the signal and get 4x the power you could make
>> gazillions! Of course, you'd be creating energy out of nothing, but
>> who cares about the laws of physics? :)
>>
> Two identical receiving antennas would provide twice the signal voltage
> if their RF outputs were connected in series.
>
> One way of doing this would be for coax feed from each antenna to be
> connected to the primary of a 1:1 RF transformer, and the secondaries of
> the two transformers were connected in series. So if each antenna
> delivered 1V from a resistive source impedance (R) of 1 ohm into a
> matched resistive load of 1 ohm, the two secondaries in series would
> provide 2V. However, the output impedance of the two secondaries would
> be twice that of each antenna, ie 2R. To preserve matching, the load
> would also have to be 2R.
>
> However, the snag is.....
> The matched power from each antenna is 1V squared divided by 1 ohm
> (=1W), but the matched power from the combined antennas is 2V squared
> divided by 2 ohms (=2W) - which is an increase of 3dB (and not 6dB).
>
> Of course, if the receiver input was not matched, and its impedance was
> much higher than R or 2R, it might be possible to benefit from adding
> the two antenna signals in this way. Has anybody tried this?

I don't think anyone would try this because every television input is
either 75 or 300 ohms or both. Hoping for an input of 1000 ohms would be
a vain hope.

[Ian Jackson]

In message <NuXyu.151932$8V.2...@en-nntp-16.dc1.easynews.com>, boomer
<nog...@invalid.com> writes

I think you might be surprised at how unlike the supposed 75 or 300 ohms
some TV sets might be.

> Hoping for an input of 1000 ohms would be a vain hope.

Possibly a purpose-built preamp could be designed to have a distinctly
higher input impedance. Of course, it would also have to have an
appropriately low noise figure (certainly at least as good as the
receiver).
--
Ian

[Jerry Stuckle]

But then I DID qualify my statement with "if the resistance (impedance
in this case) stays the same". In your case, as you indicated, it is
not the same.

For the same impedance you would need a matching network. Assuming no
loss in the matching network, the output would be 1.414V.

--
==================
Remove the "x" from my email address

[Jeff Liebermann]

On Sun, 5 Jan 2014 00:01:47 -0500, "Ralph Mowery"
<rmower...@earthlink.net> wrote:

>I understand the idea of using 'perfect' items in electronics, then going
>for more exect calculations if needed.

I like to design perfect antennas and circuits as a sanity check to
see if it can be done. Then, I throw in the losses and see what
happens. It's also a crude form of sensitivity analysis, which tells
me which parameters are most important.

>The Wilkinson combiner is possiable for relative narrow frequencies. Not
>sure if building one out of descrete components or full size transmission
>lines would be broad enough for the whole FM band either. Wild guess it
>would be about the same if just two pieces of transmission line of the
>correct impedance and length were used.

Good guess. Discrete or coaxial performance (loss, isolation, and
bandwidth) are about the same. You're also correct that it wouldn't
cover the entire FM band. I could do it with a single stage Wilkinson
combiner by lowering the Q of the components. However, that will
increase the losses, which is not a great idea.

Much better is to use a multi-stage Wilkinson combiner:
<http://www.microwaves101.com/encyclopedia/wilkinson_multistage.cfm>
It's a common stripline technique. You probably recognize the general
pattern:
<http://www.eee.bham.ac.uk/yatesac/Web%20PDF%27s/Test%20Gear/Wideband%20Wilkinson%20Coupler_1-2%20GHz_Layout.pdf>
<http://www.eee.bham.ac.uk/yatesac/Web%20Pages/Wideband%20Wilkinson%20Splitter%20&%20Combiner.htm>

>Isn't the Wilkinson combiner just two pieces of transmission line (or
>simulated with components) with a resistor across two of the ports to
>absorbe the diffeance if the loads/sources are not ballanced ?

The resistor is NOT to provide a load in case of an imbalance. It's
to provide an impedance match for a 180 degree out of phase path
between input/output ports. A signal that tries to go between the two
input/output ports has two paths along which it can go. One is down
one 1/4 wave coax, and up the other 1/4 wave coax, resulting in a 180
degree phase shift. The other is through the resistor with a 0 degree
phase shift. If everything is roughly impedance matched, the signals
through the two paths cancel, resulting in very good isolation between
ports.

>As the subject is combining, I have not looked into the losses of splitting,
>but it would be 6 db for the simple resistor designs not counting the minor
>losses. That would be 3 db for the ports and 3 db lost in the resistors.

Yep, that's correct.
<http://www.microwaves101.com/encyclopedia/resistive_splitters.cfm>

>To combind signals you would get the loss of the resistors of 3 db and a
>fraction of other loss.

Yep, that's correct.

>I am using a HP 8924C for a test set. It has just about everything you can
>think of for a service monitor. Calibrated from 30 to 1000 MHz but usuable
>uncalibrated to about a half of a mhz.
>http://www.amtronix.com/hp8924c60.htm

<http://axfp.org/god-bless-the-hp-8924c-a-tale-and-tutorial-of-the-service-monitor/>
Nice. I'm into opening a museum of antique test equipment:
<http://802.11junk.com/jeffl/pics/home/slides/test-equip-mess.html>

>Yes, phasing harnesses on antennas are not totally loseless, but will be
>mainly whatever the loss of the coax is between the elements.

Nope. A phasing harness is much like the Wilkinson combiner without
the balancing resistor. Isolation between antennas would be nice, but
kinda futile with the antennas that close. Like the Wilkinson
combiner, the cables are odd multiples of 1/4 wave electrical. Like
the Wilkinson, such phasing harnesses have a limited bandwidth, where
losses increase the further away one gets from resonance. In other
words, you can't supply a single number for the losses in a phasing
harness. What's needed are numbers for the losses at resonance and at
band edges.

At this time, I still don't know if a Wilkinson combiner or phasing
harness will have sufficient bandwidth to cover the FM broadcast band.
That's 20 Mhz bandwidth at 100 Mhz or Q=5. I don't think that's
possible. To make my life more difficult, it's not possible to easily
model coax cables using NEC2. I've been using a mythical 50 ohm open
wire line, which can be modeled.

I would recommend either a messy multistage Wilkinson power
splitter/combiner, or go the broadband route with a common CATV/FM
power splitter/combiner.

>If were the origional poster and there were not too many transmitters near
>me, I would try a good preamp first. Mast mounted if possiable as it is for
>receive only.

Preamps are a mixed blessing. With a good antenna, they can pickup
signals at impressive distances. However, they can also overload
miserably if there is a nearby transmitter on a nearby frequency. The
directionality of a Yagi is a big help, but if the nearby transmitter
is too close, the amplifier will overload, desensitize, belch
intermod, or otherwise cause problems. At best, the tower mounted amp
should be used only to compensate for coax losses. Any more gain than
that reduces the dynamic range of the system. Therefore, if the coax
cables is fairly short, and the cable is low loss, I wouldn't bother
with an amplifier. If the coax cable run is long and/or the coax is
junk, a tower mounted amp might be worth trying.

[Sal]

"Jeff Liebermann" <je...@cruzio.com> wrote in message

news:i8rlc95rs0n3lmqj2...@4ax.com...

> On Mon, 6 Jan 2014 06:28:11 +0000 (UTC), gregz <ze...@comcast.net>
> wrote:
>
>><pelot...@gmail.com> wrote:
>>> "only 3 db", but that's twice the signal. I have mine stacked 12 feet,
>>> but I believe Winegard says either 8 or 10 feet. Mine work swell. +:^] I
>>> got mine just after they were discontinued in 2005/6. Had to email a
>>> number of suppliers until I found the second one. I bet there are some
>>> still in storage somewhere, email different places that sell Winegard,
>>> you may still find one.
>>>
>>> John K9RZZ
>
>>Twice the signal means twice the voltage, for me.
>>Greg
>
> Nope. Power is by the square of the voltage:
> P = V^2 / R
> If you double the voltage, you get 4 times the power.
> A 1.414 times increase in voltage will produce twice the power.
>
> I tried to convert the antenna model of the HD-6066P antenna from the
> AO .ant format to .nec using 4NEC2 and failed. The plan was to model
> the stacked arrangement and see what happens:
> <http://www.ham-radio.com/k6sti/hd6065p.htm>
> The .ant file imported without error, the wire tables and images look
> correct, but the pattern is more like a point source than a gain
> antenna. I'll look at it later to see where I screwed up, but it
> would be nice if someone would look at the problem.

I just set up an experiment. I connected my roof antenna to my signal
level meter and read the signal strength of my Channel 10. It was 10 dBmV,
the unit typically used for TV signal strength work.

Next, I connected the same roof antenna to the inport port of one of a pair
of passive splitters connected back-to-back with equal short lengths of the
same 75-ohm cable.

Finally, I connected the output port of this network to the signal level
meter and observed a signal that was approximately 1.25 dBmV less. (A
quarter of a dBmV is about as close as I can reliably read; individual whole
number marks are only a few mm apart.)

Thus, I conclude that the 1 dB nominal loss for a passive splitter -- either
combining or splitting -- is confirmed. Combining two identical suignals
does get you something more than one, alone.

RELATED: When I used identical twin UHF antennas side-by-side, separated by
a free-space half-wave distance to cancel interference from one side, it
worked nicely and showed about the same loss figures as above. That is, my
reading for two antennas combined was about 2 dBmV higher than for either of
the twin antennas alone, thus reflecting the 1dB loss in the combiner.

Combining antennas can be an uncertain business because the phase
relationships change with wavelength; the arrangement that strengthens one
channel may weaken another channel if the respective signals come from
different directions and/or the cable lengths are not matched. It's a
matter of reinforcement or cancellation, depending on phase relationships.

"Sal"
(KD6VKW)

[gregz]

The reason big speaker systems work in large places is efficiency gain
using multiple arrays, must be in phase. As I was saying, it's a known
fact, which I have measured. You can actually get near 10 dB gain using
several speakers. It's why horn loudspeakers have gain, better impedance
matching to air.

I once believed two in phase speakers provided 3 dB increase also. I then
read a speaker project by the now famous diAppolito configuration designer
in Speaker Builder magazine 80's ?. I can try to find a reference.

Greg

[gregz]

I found a reference by a well known author designer. The other tricky added
to the equation, is using one channel amplifier, and getting twice the
power with lowered Z. It still works for two separate amps. DiAppolito and
linkwitz, two biggies of speaker systems...

http://www.linkwitzlab.com/faq.htm#Q21

Greg

[Ian Jackson]

In message <laii6h$m20$1...@dont-email.me>, Sal
<salmo...@food.poisoning.org.invalid> writes

You missed out step #2, which was to measure the output level of the
splitter alone.

Using your figures, this would have shown a signal loss of 3.625dB (3dB
power split loss and 0.625dB of circuit loss).

When you then added the combiner, you would have 3dB power split loss
and 0.625dB of circuit loss, followed by 3db power combine gain and
0.625dB of circuit loss - so as you measured, a total loss of only
1.25dB.

Despite working in the cable TV industry for 43 years, for some reason
this is an experiment I don't recall ever performing!
--
Ian

[Jerry Stuckle]

We aren't talking multiple arrays in large places. Of course multiple
speakers will provide more gain than one speaker. And horn speakers get
their "gain" by directing more energy in one direction; there is a loss
of signal in other directions. It has nothing to do with "impedance
matching to the air" (there is no such thing).

The laws of physics say it is impossible to create energy out of
nothing, which is what you would be doing if you quadrupled the power
(6db gain) by placing two speakers in phase. If you "measured" this,
you need a new meter.

I would love to tear apart your "reference".

[Jerry Stuckle]

In addition to the splitter losses, you have coax and connector loss.
Coax loss probably isn't too bad, but unless you use a high quality
crimping tool, connector loss can easily approach 0.25 to 0.5 db. Even
with a high quality crimping tool, you can get around 0.1 db per connector.

There is also the possibility of a slight phase difference of the
signals coming out of the combiner, which would also affect the output
(splitters/combiners aren't perfect, either). But I wouldn't think this
would show up at such low frequencies unless you have lab-grade test
equipment (microwave frequencies and above are a different story).

[gregz]

Non believer in facts. If you don't believe you should do tests, like me.

I'll skip the horn for now..

If you can't believe two speakers will move TWICE the air doubling
intensity, I don't know what else to say, except test yourself.

Greg

[Jerry Stuckle]

I have (I was an EE major). You can't create energy from nothing. The
laws of physics don't allow it. And I currently have a business which
deals with home entertainment systems.

At MOST, two speakers in phase can move twice the air. No more, and in
reality, because of inefficiencies, it will be less.

[boomer]

>>>
>>> We aren't talking multiple arrays in large places. Of course multiple
>>> speakers will provide more gain than one speaker. And horn speakers get
>>> their "gain" by directing more energy in one direction; there is a loss
>>> of signal in other directions. It has nothing to do with "impedance
>>> matching to the air" (there is no such thing).
>>>
>>> The laws of physics say it is impossible to create energy out of
>>> nothing,
>>> which is what you would be doing if you quadrupled the power (6db gain)
>>> by placing two speakers in phase. If you "measured" this, you need a
>>> new meter.
>>>
>>> I would love to tear apart your "reference".
>>
>> Non believer in facts. If you don't believe you should do tests, like me.
>>
>> I'll skip the horn for now..
>>
>> If you can't believe two speakers will move TWICE the air doubling
>> intensity, I don't know what else to say, except test yourself.
>>
>> Greg
>>
>
> I have (I was an EE major). You can't create energy from nothing. The
> laws of physics don't allow it. And I currently have a business which
> deals with home entertainment systems.
>
> At MOST, two speakers in phase can move twice the air. No more, and in
> reality, because of inefficiencies, it will be less.
>

I hate to question the law of conservation of energy at all, but I must
say that there could be more energy delivered from two 8 ohm speakers in
parallel than a single speaker powered by the same amplifier. Many
amplifiers have 4 ohm outputs. So, you see the possibility. You would be
delivering the same energy to both speakers as was delivered to one.

Of course for those who believe in magical energy production, no
reasoning will help.

I personally have a Crown 810 powering a couple of AR SRT380s. The
amplifier has 4 ohm outputs and the speakers are 4 ohms. There is
nothing to be done to increase sound power except buy more efficient
folded horn types. I have neither the space nor money to do so. However,
at 420 watts rms per channel as it is now, I really don't require more
power. Jimmy Hendrix sounds just fine to me. :-)

So, matching output impedance of amplifier to speaker will result in
maximum energy transfer and using the most efficient speakers will
result in of course more acoustic energy produced. All we are talking
about here is not wasting energy in poor efficiency systems.

[John S]

I would hate to have you as my neighbor. I would have to call the police
on you.

[Jerry Stuckle]

OK, so instead of putting out 100W to one eight-ohm speaker, you're
putting out 100W to two eight ohm speakers. So you have a 3db gain,
assuming the speakers are in phase.

It is no different than feeding two eight-ohm speakers from separate
100W amplifiers, and the results are the same.

--
==================
Remove the "x" from my email address

[boomer]

exactly

[boomer]

We live in the North country close to the border. Our home, as are all,
is heavily insulated. I run the music loud as I want without bothering
the neighbours. The high wattage rating per channel is mostly just for
the incredibly low terminal impedance. This makes for very good fidelity
on high power low frequency. It is called inertial dampening. You have
to run large diameter wire to keep this all working. I have the speakers
hooked up with #10 wire. I checked performance of the speakers for this
type wire by running one speaker with #16 lamp cord which I had been
using and the other one hooked up with #10. I then switched to mono on
the preamp. Using the balance control clearly showed a very noticeable
improvement. I was told to use large dia wire to keep the resistance
very low. I first thought this was really over-kill but by experiment I
found that my advisor was correct. The impedance from the amp and wiring
should be in the very low milliohms to prevent inertial overshoot.
Purple Haze definitely sounded better :-)

PS some have actually used #00 wire to their speakers. Without
experimenting myself I feel by guessing that this is over-kill. I could
be wrong, I was before.

[Ian Jackson]

In message <nuAzu.123920$SU.6...@en-nntp-16.dc1.easynews.com>, boomer
<nog...@invalid.com> writes

If I understand things correctly, I don't think that many audio
amplifiers have an output impedance as high as 4 ohms. It's generally a
fraction of an ohm. However, an amplifier will be designed to deliver a
given power into a given load with a specified maximum distortion.
--
Ian

[boomer]

That too is my understanding. I believe that connecting a 4 or 2 ohm
speaker to an amplifier rated at 8 ohms would likely cause distortion.
For those still following this thread here is a simple explanation of
inertial dampening.
http://www.crownaudio.com/media/pdf/amps/damping_factor.pdf

The output impedance of the Crown 810 is rated at less than 10
milliohms. This is an important specification when you are wanting to
hear very little distortion. There of course other important factors
including Frequency Response, Phase Response, Signal-to-Noise Ratio,
Total Harmonic Distortion (THD), Intermodulation Distortion (IMD),
Damping Factor, Slew Rate, Output Power, and Crosstalk. And of course
then there is the whole science of speakers. Amplifier design is much
easier to understand. I cannot really get my head around all the factors
that come into play designing speakers. It is complicated enough to
almost appear to be magic to me.

[gregz]

Yo only get so much damping with small wire. Most of it is determined by
the driver box design, driver, and resistance in the coil. What you gain
most is a more even driving Z to cover changes in speaker Z throughout the
response range.

Greg

[gregz]

Don't try to design a speaker using parallel midrange units. Your speaker
will fail due to the midrange gain.

Greg

[gregz]

What, horns produce magical gain.

Greg

[gregz]

You would get more distortion with lower z, but it would be mostly depend
on the volume level. Kept low, distortion would be minimal.

Here is another post about damping. It even includes getting gain from two
drivers.
It's old, been there, done that.....

http://zekfrivolous.com/sub/usenet/pierce/damp.txt

Greg

[gregz]

For interest, the other part"....

http://zekfrivolous.com/sub/usenet/pierce/damp2.txt

Greg

[Ralph Mowery]

"boomer" <nog...@invalid.com> wrote in message
news:_fDzu.213384$4q1.203346@en-nntp->

> PS some have actually used #00 wire to their speakers. Without
> experimenting myself I feel by guessing that this is over-kill. I could be
> wrong, I was before.

While going from # 20 or so speaker wire to # 10 is often helpful, I doubt
going much larger is going to help unless you have a very long run.

Lots of things are over sold to te audio people. Best one I know of is some
special oxygen free teflon wire ( or something like that) that replaces the
line cord to the wall outlet for over $ 100. Even if it actually did
something, that extra 50 or so feet of regular wire back to the breaker box
and other wire to the main power feed would make it worthless.



---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com

[Sal]

"Ian Jackson" <ianREMOVET...@g3ohx.demon.co.uk> wrote in message

>>
> You missed out step #2, which was to measure the output level of the
> splitter alone.
>
> Using your figures, this would have shown a signal loss of 3.625dB (3dB
> power split loss and 0.625dB of circuit loss).
>
> When you then added the combiner, you would have 3dB power split loss and
> 0.625dB of circuit loss, followed by 3db power combine gain and 0.625dB of
> circuit loss - so as you measured, a total loss of only 1.25dB.
>
> Despite working in the cable TV industry for 43 years, for some reason
> this is an experiment I don't recall ever performing!

Thanks Ian,

Earlier in this thread, I saw what I thought to be an error in some postings
... about losses in excess of 3dB in the combiner and a conclusion that
stacking results in less signal, which shouldn't be the case. My little
experiment was meant to demonstrate a signal increase from combining
in-phase signals in a passive device. Put another way, I wanted to show
that a >3dB loss is not inherently present in both directions.

You are correct that I did not make the measurement of the output level of
the splitter alone, since it has been made and documented on many occasions.
A real lab experiment would have measured that and the cable losses, too.
(My 35 year-old Jerrold 747 was within easy reach and "close enough.")

It was my intent to show, when two equal signals (presumptive on my part
that the two outputs of a splitter are equal) are combined, that the result
is the addition of the two, minus ohmic and coupling losses, which I think I
did show.

"Sal"

[Sal]

"Jerry Stuckle" <jstu...@attglobal.net> wrote in message
news:lajdtb$m6k$1...@dont-email.me...

< snip >

> In addition to the splitter losses, you have coax and connector loss. Coax
> loss probably isn't too bad, but unless you use a high quality crimping
> tool, connector loss can easily approach 0.25 to 0.5 db. Even with a high
> quality crimping tool, you can get around 0.1 db per connector.
>
> There is also the possibility of a slight phase difference of the signals
> coming out of the combiner, which would also affect the output
> (splitters/combiners aren't perfect, either). But I wouldn't think this
> would show up at such low frequencies unless you have lab-grade test
> equipment (microwave frequencies and above are a different story).

All correct. As I said to Ian, I wanted to show I could create two matching
signals then add them and the passive splitter/combiner output would be
greater than either input, alone. Accuracy within a dB or so was sufficient
to make the point. I wouldn't go to a professional meeting with the
demonstration rig I used last night.

Another experiment I ran (back around 1975) was to take 100 feet of cable
and measure the loss, then repeat the measurement using a different 100 feet
made from ten different pieces. Yup, the loss was about 3 dB more,
indicative of an average 0.3 dB loss per joint, neatly within the range you
specified.

"Sal"

[Sal]

"Jerry Stuckle" <jstu...@attglobal.net> wrote in message

news:lamkvd$f83$1...@dont-email.me...

>
> OK, so instead of putting out 100W to one eight-ohm speaker, you're
> putting out 100W to two eight ohm speakers. So you have a 3db gain,
> assuming the speakers are in phase.
>
> It is no different than feeding two eight-ohm speakers from separate 100W
> amplifiers, and the results are the same.

Discussion of audio amplifier power in home systems always prompts me to
relate this: I worked for a guy who was formerly a projectionist at Radio
City Music Hall in New York. He told me the sound system used amplifiers
rated at 70 watts per channel. That's a 6,000-seat theater.

He worked there a long time ago, so this not a claim of what they use today.
Use for perspective only, please.

"Sal"

[gregz]

Some of the early amps were smaller. I remember a discussion about a movie
coming in that suggested higher power. Those speakers were typically at
least 100 times more power efficient than average home speakers, or 10 dB
spl. Many were altec a7's.

Greg

[Jerry Stuckle]

On 1/9/2014 11:06 PM, gregz wrote:
> boomer <nog...@invalid.com> wrote:
<snip>

>> I personally have a Crown 810 powering a couple of AR SRT380s. The
>> amplifier has 4 ohm outputs and the speakers are 4 ohms. There is nothing
>> to be done to increase sound power except buy more efficient folded horn
>> types. I have neither the space nor money to do so. However, at 420 watts
>> rms per channel as it is now, I really don't require more power. Jimmy
>> Hendrix sounds just fine to me. :-)
>>
>
> What, horns produce magical gain.
>

They don't have gain, but some speakers are more efficient, so you have
less loss.

--
==================
Remove the "x" from my email address

Jerry, AI0K
jstu...@attglobal.net
==================

[Jerry Stuckle]

On 1/9/2014 11:21 PM, Ralph Mowery wrote:
> "boomer" <nog...@invalid.com> wrote in message
> news:_fDzu.213384$4q1.203346@en-nntp->
>> PS some have actually used #00 wire to their speakers. Without
>> experimenting myself I feel by guessing that this is over-kill. I could be
>> wrong, I was before.
>
> While going from # 20 or so speaker wire to # 10 is often helpful, I doubt
> going much larger is going to help unless you have a very long run.
>
> Lots of things are over sold to te audio people. Best one I know of is some
> special oxygen free teflon wire ( or something like that) that replaces the
> line cord to the wall outlet for over $ 100. Even if it actually did
> something, that extra 50 or so feet of regular wire back to the breaker box
> and other wire to the main power feed would make it worthless.
>

Definitely! A lot of audio people want the best sound, but are
unfamiliar with the technical aspects. This leaves them ripe for greedy
salespeople.

I remember going into circuit City a few years ago. All I needed was a
few feet of speaker wire. The salesman tried to sell me a 50' spool of
16 gauge wire for about $50. I asked him why it was so expensive - he
replied "Because it's (brand name here)". I then asked him what was so
special about Monster. His only response was "It's (brand name here)!".

I went down the street to Radio Shack and got something similar for
under $10. That was 15 or more years ago, and it's still working fine.

If you want to sell me something that's 5x the price of the competition,
you need to be ready to tell me WHY it's 5x the price. And just saying
it's because it's a certain brand doesn't work.

--
==================
Remove the "x" from my email address

[Jerry Stuckle]

Yes, this is where speaker efficiency comes into play. Due to the need
for stiffer cones, larger voice coils, etc., higher-power speakers are
generally less efficient than lower power ones. So 10W into a 10W-rated
speaker will provide a higher SPL than that same 10W into a 100W speaker.

And, of course, speaker placement is also critical, especially in larger
venues. You can cover a large area with not a lot of power if the
system is designed properly.

[Irv Finkleman]

In a circa 1970s issue of Stereo Review there was a cartoon showing the
Front Window of a Stereo Dealers. There was a sign advertising an OLD
FOLKS SPECIAL -- a speaker with a frequency response of 500Hz to
5KHz. A caption stated 'Why Pay Good Money For Sound You Can
No Longer Hear?'

Incidentally, if you Google Wickipedia there are a number of articles
on 'speaker damping factor'. In those days I didn't know much math
or physics, so I just used line cord to hook up the speakers. They
sounded great to me! Those were also the days when if you turned up
(or down) the Bass and Treble controls you were in danger of being
poo-pooed by your audiophile friends!

Irv VE6BP


--
Political correctness is a doctrine, fostered by a delusional, illogical
minority, and rapidly promoted by an unscrupulous mainstream media, which
holds forth the proposition that it is entirely possible to pick up a piece
of shit by the clean end.

"Jerry Stuckle" <jstu...@attglobal.net> wrote in message

news:laoo55$9mr$1...@dont-email.me...

[Ralph Mowery]

"Jerry Stuckle" <jstu...@attglobal.net> wrote in message
news:laoo55$9mr$1...@dont-email.me...
>

> If you want to sell me something that's 5x the price of the competition,
> you need to be ready to tell me WHY it's 5x the price. And just saying
> it's because it's a certain brand doesn't work.
>

Had he told people the wire was teflon coated so the electrons flowed beter
and the copper was oxygen free so the electrons would not be degraded, he
could have sold it..

From what I have been seeing the TV people are about the same, Selling high
dollar hdmi cable or special high defination antennas with the same snake
oil pitch.

[Ralph Mowery]

"Sal" <salmonella@food poisoning.org> wrote in message
news:lao1bf$u04$1...@dont-email.me...

>
>> Discussion of audio amplifier power in home systems always prompts me to
> relate this: I worked for a guy who was formerly a projectionist at Radio
> City Music Hall in New York. He told me the sound system used amplifiers
> rated at 70 watts per channel. That's a 6,000-seat theater.
>
> He worked there a long time ago, so this not a claim of what they use
> today. Use for perspective only, please.

I wonder if that was 'real watts' instead of inflated watts. I have seen
some wall wart computer speakers rated at 50 watts or so. Open them up and
inside the speaker may have 3 watts on the lable.

Same as with the listed gain of antennas for hams and especially the CB.
One antenna of modern times had a gain listed of several times more than it
should. Claimed to be the gain from one of the computer programs. It may
have been,but they were adding in a lot of ground gain and certain take off
angles.

Not sure where they were getting the gain numbers from,but he old CC 11
element 2 meter beams had a number that was way too high if you compaired it
on the air with another antenna.

[Jerry Stuckle]

On 1/10/2014 10:55 AM, Ralph Mowery wrote:
> "Jerry Stuckle" <jstu...@attglobal.net> wrote in message
> news:laoo55$9mr$1...@dont-email.me...
>>
>> If you want to sell me something that's 5x the price of the competition,
>> you need to be ready to tell me WHY it's 5x the price. And just saying
>> it's because it's a certain brand doesn't work.
>>
>
> Had he told people the wire was teflon coated so the electrons flowed beter
> and the copper was oxygen free so the electrons would not be degraded, he
> could have sold it..
>
> From what I have been seeing the TV people are about the same, Selling high
> dollar hdmi cable or special high defination antennas with the same snake
> oil pitch.
>
>

Yup, I know what you mean. There are some major differences between
different HDMI cables; they'll all work pretty well at five feet, but
many of the cheaper brands (and a bunch of what you see on TV) won't
work at 50 feet (the maximum for the spec). For some, even 15 feet is
problematical.

Best is to buy from a reputable high-end dealer, especially if it's a
local store and not a chain. They know their stuff.

--
==================
Remove the "x" from my email address

Jerry, AI0K
jstu...@attglobal.net
==================

[Jeff Liebermann]

On Thu, 9 Jan 2014 21:08:11 -0800, "Sal" <salmonella@food
poisoning.org> wrote:

>Another experiment I ran (back around 1975) was to take 100 feet of cable
>and measure the loss, then repeat the measurement using a different 100 feet
>made from ten different pieces. Yup, the loss was about 3 dB more,
>indicative of an average 0.3 dB loss per joint, neatly within the range you
>specified.

0.3dB per connector at what frequency?

This is more fun:
<http://802.11junk.com/jeffl/antennas/connector-loss/index.html>
Just take every connector that you can find, put them in series, and
measure the loss. In this case, it was done at 2.4Ghz and 450MHz. End
to end loss at 2.4GHz was 2dB for about 25 adapters or about 0.08dB
per adapter. At 250MHz, the loss was about 0.2dB or 0.008dB per
adapter.

I've done similar demonstrations using two wattmeters at the local
radio club meeting. The results are typically that the adapter string
has the same loss as an equivalent length of small coax cable. I had
a surplus of BNC T connectors, so a strung about 50 of them in series
and obtained similar results.

Bottom line: Connectors and adapters aren't as evil as the data
sheets and literature suggest.


--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Jerry Stuckle]

If it was a long time ago, I suspect it was "real watts". Manufacturers
didn't really start inflating the wattage until the 70's or so.

Nowadays, a "100W" amplifier is probably more like 20 "real" watts.

--
==================
Remove the "x" from my email address

Jerry, AI0K
jstu...@attglobal.net
==================

[Ian Jackson]

In message <7sb0d99db0mbcpg97...@4ax.com>, Jeff Liebermann
<je...@cruzio.com> writes

>On Thu, 9 Jan 2014 21:08:11 -0800, "Sal" <salmonella@food
>poisoning.org> wrote:
>
>>Another experiment I ran (back around 1975) was to take 100 feet of cable
>>and measure the loss, then repeat the measurement using a different 100 feet
>>made from ten different pieces. Yup, the loss was about 3 dB more,
>>indicative of an average 0.3 dB loss per joint, neatly within the range you
>>specified.
>
>0.3dB per connector at what frequency?
>
>This is more fun:
><http://802.11junk.com/jeffl/antennas/connector-loss/index.html>
>Just take every connector that you can find, put them in series, and
>measure the loss. In this case, it was done at 2.4Ghz and 450MHz. End
>to end loss at 2.4GHz was 2dB for about 25 adapters or about 0.08dB
>per adapter. At 250MHz, the loss was about 0.2dB or 0.008dB per
>adapter.
>
>I've done similar demonstrations using two wattmeters at the local
>radio club meeting. The results are typically that the adapter string
>has the same loss as an equivalent length of small coax cable. I had
>a surplus of BNC T connectors, so a strung about 50 of them in series
>and obtained similar results.
>
>Bottom line: Connectors and adapters aren't as evil as the data
>sheets and literature suggest.
>

I've always assumed that the loss measured through connectors and
adapters was mainly
(a) because they have unavoidable length (ie not a lot), and
(b) because the impedance match through them is less than perfect (ie
not a lot).
The ohmic contact resistance may also be a tiny tad higher than the same
length of coax (even less).
--
Ian

[Sal]

"Ralph Mowery" <rmower...@earthlink.net> wrote in message
news:H7udnSOwR4lHhE3P...@earthlink.com...

Hard to know, Ralph. Some years ago, I was the repairman for my son's high
school music group, a show choir that traveled with a serious suite of
electronics. One evening, I changed a bad tweeter in a big roll-around
speaker system and tested it before I put it in my van. I clipped leads on
the speaker terminals and plugged into the headphone jack on a small
boombox -- powered by four D-cells. When I began to crank it up on the
patio, my lovely wife came roaring out and demanded that I turn it down.
"Do you know what time it is?"

Well, yes, I did know, but that wasn't exactly her point. Clearly, four
D-cells provide more than enough sound power to upset a whole neighborhood
and she felt the need to heighten my concern. ;-)

"Sal"

[Jerry Stuckle]

The main loss in a connector is due to the impedance bump at the
connector. This can be easily seen on a TDR (Time Domain Reflectometry)
display.

Some connectors are better than others; for instance, the older F
connectors which are crimped down with a ring are the worst. Next is
the connector where the crimp is a hex crimp - it doesn't give a
consistent impedance around the connector.

The best (and the ones we use) compress the entire base of the connector
evenly, creating a smooth crimp. The end of the coax is evenly covered
by the connector.

The other problem is the technician installing the connectors. I've
seen great ones, and not-so-great ones. There are a lot of chances for
going wrong - for instance, it's easy to screw up the braid when trying
to insert a crimp-on connector under the outer jacket and shield. And
soldering connectors (i.e. PL-259 and N) is almost sure to give you a
huge bump (and loss) because it's almost impossible to solder the shield
without melting the inner insulator to some point. It may not short
out, but that doesn't mean you don't have loss there.

[Jeff Liebermann]

On Sat, 11 Jan 2014 00:01:57 +0000, Ian Jackson
<ianREMOVET...@g3ohx.demon.co.uk> wrote:

>In message <7sb0d99db0mbcpg97...@4ax.com>, Jeff Liebermann
><je...@cruzio.com> writes
>>On Thu, 9 Jan 2014 21:08:11 -0800, "Sal" <salmonella@food
>>poisoning.org> wrote:
>>
>>>Another experiment I ran (back around 1975) was to take 100 feet of cable
>>>and measure the loss, then repeat the measurement using a different 100 feet
>>>made from ten different pieces. Yup, the loss was about 3 dB more,
>>>indicative of an average 0.3 dB loss per joint, neatly within the range you
>>>specified.
>>
>>0.3dB per connector at what frequency?
>>
>>This is more fun:
>><http://802.11junk.com/jeffl/antennas/connector-loss/index.html>
>>Just take every connector that you can find, put them in series, and
>>measure the loss. In this case, it was done at 2.4Ghz and 450MHz. End
>>to end loss at 2.4GHz was 2dB for about 25 adapters or about 0.08dB
>>per adapter. At 250MHz, the loss was about 0.2dB or 0.008dB per

Oops. That should be 450 Mhz, not 250 MHz.

>>adapter.
>>
>>I've done similar demonstrations using two wattmeters at the local
>>radio club meeting. The results are typically that the adapter string
>>has the same loss as an equivalent length of small coax cable. I had
>>a surplus of BNC T connectors, so a strung about 50 of them in series
>>and obtained similar results.
>>
>>Bottom line: Connectors and adapters aren't as evil as the data
>>sheets and literature suggest.

>I've always assumed that the loss measured through connectors and
>adapters was mainly
>(a) because they have unavoidable length (ie not a lot), and
>(b) because the impedance match through them is less than perfect (ie
>not a lot).

As I misunderstand it, below about 1GHz, most of the loss is ohmic,
which are the surface and contact resistance of the connections and
conductors. Above 1GHz, the dielectric losses begin to become
significant. Extra points of dissimilar metals and bad construction.
Except for the PL-259/SO-239 and phono connectors, most of the
connectors are fairly close to 50 ohms.

>The ohmic contact resistance may also be a tiny tad higher than the same
>length of coax (even less).

Yep. It's more than a tiny tad higher. For example, at 2.4 GHz,
LMR240 has an attenuation of 12.6 dB/100ft. Each coax adapter is
maybe an inch long, resulting in:
12.6 dB/100ft = 0.126 dB/ft = 0.01 dB/inch
which is 8 times less than the 0.08dB/adapter that the measurements
show. However, there's plenty of room for measurement error here. I
suspect that if quality connectors were used, such as SMA, the numbers
could come out closer to a similar wire gauge coax cable.

[Sal]

"Jeff Liebermann" <je...@cruzio.com> wrote in message
news:7sb0d99db0mbcpg97...@4ax.com...

> On Thu, 9 Jan 2014 21:08:11 -0800, "Sal" <salmonella@food
> poisoning.org> wrote:
>
>>Another experiment I ran (back around 1975) was to take 100 feet of cable
>>and measure the loss, then repeat the measurement using a different 100
>>feet
>>made from ten different pieces. Yup, the loss was about 3 dB more,
>>indicative of an average 0.3 dB loss per joint, neatly within the range
>>you
>>specified.
>
> 0.3dB per connector at what frequency?
>
> This is more fun:
> <http://802.11junk.com/jeffl/antennas/connector-loss/index.html>
> Just take every connector that you can find, put them in series, and
> measure the loss. In this case, it was done at 2.4Ghz and 450MHz. End
> to end loss at 2.4GHz was 2dB for about 25 adapters or about 0.08dB
> per adapter. At 250MHz, the loss was about 0.2dB or 0.008dB per
> adapter.
>
> I've done similar demonstrations using two wattmeters at the local
> radio club meeting. The results are typically that the adapter string
> has the same loss as an equivalent length of small coax cable. I had
> a surplus of BNC T connectors, so a strung about 50 of them in series
> and obtained similar results.
>
> Bottom line: Connectors and adapters aren't as evil as the data
> sheets and literature suggest.

I agree.

To answer your question, my test generator output was Channel 3, so my
measurements were done about 61 MHz. I used all F-connectors, too, not
exactly a precision connector.

The reason I did the experiment [on USS Oriskany (CV-34), by the way] was
because my prior duties as an Electronic Warfare Tech exposed me to a
persistent rumor: Connectors cause a 3dB loss. I knew that it was nonsense
but I had never taken the time to conclusively disprove it before I moved to
the TV shop.

Related: I'm in a local group that's experimenting with mesh networking
(http://www.broadband-hamnet.org/). My first antenna connection required a
stack of four adapters, so last week I bought eight different adapters. I
should need only one. My big concern is not signal loss but the possibility
of snapping something plastic with a stupid long stack of connectors on the
back of a router.

"Sal"

[Jeff Liebermann]

On Fri, 10 Jan 2014 19:36:59 -0500, Jerry Stuckle
<jstu...@attglobal.net> wrote:

>The main loss in a connector is due to the impedance bump at the
>connector. This can be easily seen on a TDR (Time Domain Reflectometry)
>display.

Rubbish. Let's pretend that I mix in a 75 ohm coax connector into a
50 ohm system. Depending on the location of this "impedance bump",
the VSWR is no more than 1.5:1 which is generally considered marginal.
That's 0.18dB of mismatch loss.
<http://www.microwaves101.com/encyclopedia/calvswr.cfm>
If you're doing satellite or microwave DX work, then 0.18dB might be
important. However, for most other applications, it's a trivial
amount.

You might be amused to know that most of my rooftop antennas are fed
with 75 ohm coax and that my favored antenna designs are also 75 ohm.
There are various reasons, but the main one is that coax cable losses
are less at 75 ohms, than at 50 ohms. 50 ohms can handle more power,
but 75 ohms has less loss.
<http://www.belden.com/blog/broadcastav/50-Ohms-The-Forgotten-Impedance.cfm>
The only problems I have with 75 ohms is finding the proper connectors
and dealing with the pads needed to make my 50 ohm test equipment look
like 75 ohms. (Actually the real reason is that the 75 ohm stuff is
mostly CATV surplus, which tends to be really cheap).

More:
<http://www.qsl.net/n9zia/wireless/75_ohm_hardline.html>

>Some connectors are better than others; for instance, the older F
>connectors which are crimped down with a ring are the worst. Next is
>the connector where the crimp is a hex crimp - it doesn't give a
>consistent impedance around the connector.

I rip those out wherever I find them, even if they're on the ends of
commercially crimped cables (usually RG-59/u which is another
nightmare). However, the loss mechanism with the old CATV coax and
associated crappy crimp connectors was radiation, not mismatch loss.
The ground connections would fall apart, turning the coax shield into
an impressive antenna.

>The best (and the ones we use) compress the entire base of the connector
>evenly, creating a smooth crimp. The end of the coax is evenly covered
>by the connector.

I've had problems with some of those push-on connectors. I also don't
want to stock a zillion different connector variations from different
vendors. So, I've standardized on the "red" univeral T&B SNS1P6U
RG-6/u connectors:
<www.ebay.com/sch/i.html?_nkw=SNS1P6U>

>The other problem is the technician installing the connectors. I've
>seen great ones, and not-so-great ones. There are a lot of chances for
>going wrong - for instance, it's easy to screw up the braid when trying
>to insert a crimp-on connector under the outer jacket and shield. And
>soldering connectors (i.e. PL-259 and N) is almost sure to give you a
>huge bump (and loss) because it's almost impossible to solder the shield
>without melting the inner insulator to some point. It may not short
>out, but that doesn't mean you don't have loss there.

Actually, it's not the crimp job that kills the connection. It's the
stripping of the coax that causes the most problems. I use various
rotary contrivances that have razor blades to make the cuts at the
correct spacing. Those work well initially, but after about 50
connectors, the blades become dull and useless. Of course, nobody has
spare blades or knows how to adjust them. They either continue to use
a dull razor or steal my new stripper.

Oops... dinner... gone.

[Ralph Mowery]

"Jeff Liebermann" <je...@cruzio.com> wrote in message

news:qt71d91431dhbhjc0...@4ax.com...

> On Fri, 10 Jan 2014 19:36:59 -0500, Jerry Stuckle

>> Actually, it's not the crimp job that kills the connection. It's the
> stripping of the coax that causes the most problems. I use various
> rotary contrivances that have razor blades to make the cuts at the
> correct spacing. Those work well initially, but after about 50
> connectors, the blades become dull and useless. Of course, nobody has
> spare blades or knows how to adjust them. They either continue to use
> a dull razor or steal my new stripper.
>

I don't know the quality of the cutters you use, but I have bought several
from China off ebay for about $ 2 each including shipping. For the very few
connectors I do, they work. At that price, you could order a lot of them
and not worry about the replacement blades. Just like the disposiable
razors. They seem identical to the ones that sell in stores for $ 10 to $
15 .

[Jerry Stuckle]

On 1/10/2014 9:06 PM, Jeff Liebermann wrote:
> On Fri, 10 Jan 2014 19:36:59 -0500, Jerry Stuckle
> <jstu...@attglobal.net> wrote:
>
>> The main loss in a connector is due to the impedance bump at the
>> connector. This can be easily seen on a TDR (Time Domain Reflectometry)
>> display.
>
> Rubbish. Let's pretend that I mix in a 75 ohm coax connector into a
> 50 ohm system. Depending on the location of this "impedance bump",
> the VSWR is no more than 1.5:1 which is generally considered marginal.
> That's 0.18dB of mismatch loss.
> <http://www.microwaves101.com/encyclopedia/calvswr.cfm>
> If you're doing satellite or microwave DX work, then 0.18dB might be
> important. However, for most other applications, it's a trivial
> amount.
>

That's theoretical. Reality is much different. Have you ever worked
with a TDR? It's one of the tools we use regularly (and an expensive
one, also).

> You might be amused to know that most of my rooftop antennas are fed
> with 75 ohm coax and that my favored antenna designs are also 75 ohm.
> There are various reasons, but the main one is that coax cable losses
> are less at 75 ohms, than at 50 ohms. 50 ohms can handle more power,
> but 75 ohms has less loss.
> <http://www.belden.com/blog/broadcastav/50-Ohms-The-Forgotten-Impedance.cfm>
> The only problems I have with 75 ohms is finding the proper connectors
> and dealing with the pads needed to make my 50 ohm test equipment look
> like 75 ohms. (Actually the real reason is that the 75 ohm stuff is
> mostly CATV surplus, which tends to be really cheap).
>

So? Dipoles aren't 50 ohm antennas. They're typically closer to 75 ohm.

As for handling more power - rubbish. The current in 75 ohm coax is
lower than that in 50 ohm coax, for the same power rating.

Proper connectors are no problem when you can buy from commercial
distributors. But we don't typically sell them individually.

> More:
> <http://www.qsl.net/n9zia/wireless/75_ohm_hardline.html>
>
>> Some connectors are better than others; for instance, the older F
>> connectors which are crimped down with a ring are the worst. Next is
>> the connector where the crimp is a hex crimp - it doesn't give a
>> consistent impedance around the connector.
>
> I rip those out wherever I find them, even if they're on the ends of
> commercially crimped cables (usually RG-59/u which is another
> nightmare). However, the loss mechanism with the old CATV coax and
> associated crappy crimp connectors was radiation, not mismatch loss.
> The ground connections would fall apart, turning the coax shield into
> an impressive antenna.
>

We use RG-59 where appropriate, like from an outlet to the set top box.
But our in-wall coax runs are all RG-6 quad-shielded.

But we're also doing less and less coax and more and more Category cable
nowadays.

>> The best (and the ones we use) compress the entire base of the connector
>> evenly, creating a smooth crimp. The end of the coax is evenly covered
>> by the connector.
>
> I've had problems with some of those push-on connectors. I also don't
> want to stock a zillion different connector variations from different
> vendors. So, I've standardized on the "red" univeral T&B SNS1P6U
> RG-6/u connectors:
> <www.ebay.com/sch/i.html?_nkw=SNS1P6U>
>

They're OK for the hobbyist, but I don't know of any professionals who
use them. In fact, checking our main wholesalers, they aren't even
available through them (but other Beldon products are).

>> The other problem is the technician installing the connectors. I've
>> seen great ones, and not-so-great ones. There are a lot of chances for
>> going wrong - for instance, it's easy to screw up the braid when trying
>> to insert a crimp-on connector under the outer jacket and shield. And
>> soldering connectors (i.e. PL-259 and N) is almost sure to give you a
>> huge bump (and loss) because it's almost impossible to solder the shield
>> without melting the inner insulator to some point. It may not short
>> out, but that doesn't mean you don't have loss there.
>
> Actually, it's not the crimp job that kills the connection. It's the
> stripping of the coax that causes the most problems. I use various
> rotary contrivances that have razor blades to make the cuts at the
> correct spacing. Those work well initially, but after about 50
> connectors, the blades become dull and useless. Of course, nobody has
> spare blades or knows how to adjust them. They either continue to use
> a dull razor or steal my new stripper.
>
> Oops... dinner... gone.
>

Stripping is almost never a problem, unless you're a real klutz. Even
if you nick the braid a bit it isn't very critical.

We use the same type of rotary stripper - but just because it's much
faster. One of our techs can install an F connector in a minute or less
with one of them.

I never counted how many connections we get out of a stripper, but it's
got to be in the thousands. We replace some screwdrivers more often
than the strippers :)

[Ralph Mowery]

"Jeff Liebermann" <je...@cruzio.com> wrote in message

news:7sb0d99db0mbcpg97...@4ax.com...

>> This is more fun:
> <http://802.11junk.com/jeffl/antennas/connector-loss/index.html>
> Just take every connector that you can find, put them in series, and
> measure the loss. In this case, it was done at 2.4Ghz and 450MHz. End
> to end loss at 2.4GHz was 2dB for about 25 adapters or about 0.08dB
> per adapter. At 250MHz, the loss was about 0.2dB or 0.008dB per
> adapter.
>
> I've done similar demonstrations using two wattmeters at the local
> radio club meeting. The results are typically that the adapter string
> has the same loss as an equivalent length of small coax cable. I had

I have done something similar. Hook all the adaptors I could find to my hp
8924c and sweep from 30 to 1000 mhz (limit of the equipment). Not much loss
at all.

Best demonstration is to apply power. Even at 1 db of loss and running 1 kw
you would have over 100 watts of heat. Enough to burn your hand in a few
seconds.

The only way I have seen demonstrared is when the connectors creat an
impedance bump and it may take a couple of them in series so the effects
multiply much greater than just adding the losses.
They may have to be a certain ammount of wavelength apart for this to hapen.
The effect is that you have a long piece of coax with a very high SWR.

[Jerry Stuckle]

On 1/10/2014 10:23 PM, Ralph Mowery wrote:
> "Jeff Liebermann" <je...@cruzio.com> wrote in message
> news:qt71d91431dhbhjc0...@4ax.com...
>> On Fri, 10 Jan 2014 19:36:59 -0500, Jerry Stuckle
>>> Actually, it's not the crimp job that kills the connection. It's the
>> stripping of the coax that causes the most problems. I use various
>> rotary contrivances that have razor blades to make the cuts at the
>> correct spacing. Those work well initially, but after about 50
>> connectors, the blades become dull and useless. Of course, nobody has
>> spare blades or knows how to adjust them. They either continue to use
>> a dull razor or steal my new stripper.
>>
>
> I don't know the quality of the cutters you use, but I have bought several
> from China off ebay for about $ 2 each including shipping. For the very few
> connectors I do, they work. At that price, you could order a lot of them
> and not worry about the replacement blades. Just like the disposiable
> razors. They seem identical to the ones that sell in stores for $ 10 to $
> 15 .
>
>

Ralph,

They may seem identical, but they aren't. The $10-15 ones last much,
much longer. However, unless you're doing it full time, it probably
doesn't pay to get the more expensive ones.

We tried one of the cheap ones. After about 3 weeks the tech threw it
as far as he could because he was so frustrated. The ones we have now
typically last a year or more (we don't really track them).

[Jeff Liebermann]

On Fri, 10 Jan 2014 22:23:17 -0500, "Ralph Mowery"
<rmower...@earthlink.net> wrote:

>
>"Jeff Liebermann" <je...@cruzio.com> wrote in message
>news:qt71d91431dhbhjc0...@4ax.com...
>> On Fri, 10 Jan 2014 19:36:59 -0500, Jerry Stuckle
>>> Actually, it's not the crimp job that kills the connection. It's the
>> stripping of the coax that causes the most problems. I use various
>> rotary contrivances that have razor blades to make the cuts at the
>> correct spacing. Those work well initially, but after about 50
>> connectors, the blades become dull and useless. Of course, nobody has
>> spare blades or knows how to adjust them. They either continue to use
>> a dull razor or steal my new stripper.

>I don't know the quality of the cutters you use, but I have bought several
>from China off ebay for about $ 2 each including shipping. For the very few
>connectors I do, they work. At that price, you could order a lot of them
>and not worry about the replacement blades. Just like the disposiable
>razors. They seem identical to the ones that sell in stores for $ 10 to $
>15 .

Those are the same cutters that I like to use. Good, cheap, easy to
use, and throw away when dull. (I've tried resharpening the blades
with poor results).

This style is my favorite:
<http://www.ebay.com/itm/400525856013>
but these also work and are usually cheaper:
<http://www.ebay.com/itm/360806269903>
There are other designs, but I haven't used them.

[Jeff Liebermann]

On Fri, 10 Jan 2014 18:06:54 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:
(...)

>Actually, it's not the crimp job that kills the connection. It's the
>stripping of the coax that causes the most problems. I use various
>rotary contrivances that have razor blades to make the cuts at the
>correct spacing. Those work well initially, but after about 50
>connectors, the blades become dull and useless. Of course, nobody has
>spare blades or knows how to adjust them. They either continue to use
>a dull razor or steal my new stripper.
>
>Oops... dinner... gone.

The problem with the dull cutter usually creates problems where the
dielectric ends, and where the solid center conductor is exposed. The
dull blade pushes the aluminum shield over the end of the dielectric,
shorting the aluminum or the braid wire to the center conductor. Even
if it doesn't immediately short, some movement of the cable can cause
it to short. When it gets to this point, I have to take a sharp knife
and cut back the shielding so that it won't short. However, once the
connector is pushed in place, it can't be checked or repaired.

I can offer several other ways to do it wrong, but that should suffice
for now.

[Jerry Stuckle]

On 1/10/2014 11:13 PM, Jeff Liebermann wrote:
> On Fri, 10 Jan 2014 18:06:54 -0800, Jeff Liebermann <je...@cruzio.com>
> wrote:
> (...)
>> Actually, it's not the crimp job that kills the connection. It's the
>> stripping of the coax that causes the most problems. I use various
>> rotary contrivances that have razor blades to make the cuts at the
>> correct spacing. Those work well initially, but after about 50
>> connectors, the blades become dull and useless. Of course, nobody has
>> spare blades or knows how to adjust them. They either continue to use
>> a dull razor or steal my new stripper.
>>
>> Oops... dinner... gone.
>
> The problem with the dull cutter usually creates problems where the
> dielectric ends, and where the solid center conductor is exposed. The
> dull blade pushes the aluminum shield over the end of the dielectric,
> shorting the aluminum or the braid wire to the center conductor. Even
> if it doesn't immediately short, some movement of the cable can cause
> it to short. When it gets to this point, I have to take a sharp knife
> and cut back the shielding so that it won't short. However, once the
> connector is pushed in place, it can't be checked or repaired.
>
> I can offer several other ways to do it wrong, but that should suffice
> for now.
>

We don't let them get even close to that dullness. Our techs can tell
when they're starting to get dull and replace them because problems will
start much before when the shield pushes the shield over. For instance,
the inner dielectric will distort, making it harder to install the
connector.

[Ralph Mowery]

"Jerry Stuckle" <jstu...@attglobal.net> wrote in message

news:laqfj1$1ki$1...@dont-email.me...

,
>
> They may seem identical, but they aren't. The $10-15 ones last much, much
> longer. However, unless you're doing it full time, it probably doesn't
> pay to get the more expensive ones.
>
> We tried one of the cheap ones. After about 3 weeks the tech threw it as
> far as he could because he was so frustrated. The ones we have now
> typically last a year or more (we don't really track them).
>

You probably do more connectors in a week than I will ever do. For me , it
won't pay, but for you it will if they last that much longer. Must be the
quality of the blades as I can not tell any differance in the couple I
bought from China for $ 2 and the one I bought here for $ 15.
I just bought one for each size and type of cable I use.
I don't do the TV connectors, just the BNC,N,PL259 types.

[Ian Jackson]

In message <laq3n8$esh$1...@dont-email.me>, Jerry Stuckle
<jstu...@attglobal.net> writes

>

>
>The best (and the ones we use) compress the entire base of the
>connector evenly, creating a smooth crimp. The end of the coax is
>evenly covered by the connector.
>

In the CATV industry, for F-connectors, isn't Snap-n-Seal now de the
norm?
>
--
Ian

[Jerry Stuckle]

On 1/10/2014 11:39 PM, Ralph Mowery wrote:
> "Jerry Stuckle" <jstu...@attglobal.net> wrote in message
> news:laqfj1$1ki$1...@dont-email.me...
> ,
>>
>> They may seem identical, but they aren't. The $10-15 ones last much, much
>> longer. However, unless you're doing it full time, it probably doesn't
>> pay to get the more expensive ones.
>>
>> We tried one of the cheap ones. After about 3 weeks the tech threw it as
>> far as he could because he was so frustrated. The ones we have now
>> typically last a year or more (we don't really track them).
>>
>
> You probably do more connectors in a week than I will ever do. For me , it
> won't pay, but for you it will if they last that much longer. Must be the
> quality of the blades as I can not tell any differance in the couple I
> bought from China for $ 2 and the one I bought here for $ 15.
> I just bought one for each size and type of cable I use.
> I don't do the TV connectors, just the BNC,N,PL259 types.
>
>

Yup, one tech can do upwards of 50 connectors a day on a large project.
Mostly F and RJ-45, but also some RCA and others. It counts up
quickly! :)

[Jerry Stuckle]

On 1/11/2014 5:24 AM, Jeff wrote:
>
>>
>> As for handling more power - rubbish. The current in 75 ohm coax is
>> lower than that in 50 ohm coax, for the same power rating.
>>
>

> Can you not see the stupidity if that remark???
>
> Jeff
>

It is perfectly true. P=I^2xR. As R increases, I MUST decrease to
handle the same power. And since current is the limiting factor in
wire, you don't need as large a gauge of wire to handle more power.

You really should learn what you're talking about before opening your
"mouth". You only continue to show your ignorance.

[Jerry Stuckle]

Maybe for cable companies who are trying to be cheap. But the
professional integrators around here all use crimp-on. Not much more
expensive and saving one callback pays for a lot of connectors.

[Ian Jackson]

In message <larjkh$1fo$2...@dont-email.me>, Jerry Stuckle

<jstu...@attglobal.net> writes
>On 1/11/2014 3:44 AM, Ian Jackson wrote:
>> In message <laq3n8$esh$1...@dont-email.me>, Jerry Stuckle
>> <jstu...@attglobal.net> writes
>>>
>>
>>>
>>> The best (and the ones we use) compress the entire base of the
>>> connector evenly, creating a smooth crimp. The end of the coax is
>>> evenly covered by the connector.
>>>
>> In the CATV industry, for F-connectors, isn't Snap-n-Seal now de the norm?
>>>
>
>Maybe for cable companies who are trying to be cheap. But the
>professional integrators around here all use crimp-on. Not much more
>expensive and saving one callback pays for a lot of connectors.
>

Snap-n-Seal certainly isn't trying to be cheap.
https://www.google.co.uk/#q=snap+and+seal
They enable an essentially watertight seal to be obtained without
distorting (or even scratching) the connector, and therefore have little
measurable effect on the impedance.
--
Ian

[Jerry Stuckle]

That's their claim, anyway.

As I said - none of the professional integrators around here use it.
The distributors don't even carry it.

--
==================
Remove the "x" from my email address

Jerry Stuckle
JDS Computer Training Corp.
jstu...@attglobal.net
==================

[Ian Jackson]

In message <laro4l$q9e$1...@dont-email.me>, Jerry Stuckle

<jstu...@attglobal.net> writes
>On 1/11/2014 10:25 AM, Ian Jackson wrote:
>> In message <larjkh$1fo$2...@dont-email.me>, Jerry Stuckle
>> <jstu...@attglobal.net> writes
>>> On 1/11/2014 3:44 AM, Ian Jackson wrote:
>>>> In message <laq3n8$esh$1...@dont-email.me>, Jerry Stuckle
>>>> <jstu...@attglobal.net> writes
>>>>>
>>>>
>>>>>
>>>>> The best (and the ones we use) compress the entire base of the
>>>>> connector evenly, creating a smooth crimp. The end of the coax is
>>>>> evenly covered by the connector.
>>>>>
>>>> In the CATV industry, for F-connectors, isn't Snap-n-Seal now de the
>>>> norm?
>>>>>
>>>
>>> Maybe for cable companies who are trying to be cheap. But the
>>> professional integrators around here all use crimp-on. Not much more
>>> expensive and saving one callback pays for a lot of connectors.
>>>
>> Snap-n-Seal certainly isn't trying to be cheap.
>> https://www.google.co.uk/#q=snap+and+seal
>> They enable an essentially watertight seal to be obtained without
>> distorting (or even scratching) the connector, and therefore have little
>> measurable effect on the impedance.
>
>That's their claim, anyway.

And they are true!

>
>As I said - none of the professional integrators around here use it

"Professional integrators" covers a multitude of sins. Professional in
what field?

>. The distributors don't even carry it.
>

I suppose it depends which distributors you use. Such connectors are
hardly unknown in the USA.
www.tnb.com/pubint/docs/snapnseal.pdf

In the UK cable TV industry, for most applications, it would be a
hanging offence not to use an approved Snap-N-Seal connector.
--
Ian

[Jerry Stuckle]

On 1/11/2014 11:08 AM, Ian Jackson wrote:
> In message <laro4l$q9e$1...@dont-email.me>, Jerry Stuckle
> <jstu...@attglobal.net> writes
>> On 1/11/2014 10:25 AM, Ian Jackson wrote:
>>> In message <larjkh$1fo$2...@dont-email.me>, Jerry Stuckle
>>> <jstu...@attglobal.net> writes
>>>> On 1/11/2014 3:44 AM, Ian Jackson wrote:
>>>>> In message <laq3n8$esh$1...@dont-email.me>, Jerry Stuckle
>>>>> <jstu...@attglobal.net> writes
>>>>>>
>>>>>
>>>>>>
>>>>>> The best (and the ones we use) compress the entire base of the
>>>>>> connector evenly, creating a smooth crimp. The end of the coax is
>>>>>> evenly covered by the connector.
>>>>>>
>>>>> In the CATV industry, for F-connectors, isn't Snap-n-Seal now de the
>>>>> norm?
>>>>>>
>>>>
>>>> Maybe for cable companies who are trying to be cheap. But the
>>>> professional integrators around here all use crimp-on. Not much more
>>>> expensive and saving one callback pays for a lot of connectors.
>>>>
>>> Snap-n-Seal certainly isn't trying to be cheap.
>>> https://www.google.co.uk/#q=snap+and+seal
>>> They enable an essentially watertight seal to be obtained without
>>> distorting (or even scratching) the connector, and therefore have little
>>> measurable effect on the impedance.
>>
>> That's their claim, anyway.
>
> And they are true!

That is their claim, anyway.

>>
>> As I said - none of the professional integrators around here use it
>
> "Professional integrators" covers a multitude of sins. Professional in
> what field?
>

No, there is only one field of "Professional Integration". It covers
everything from CCTV to security to automation systems to theaters (home
and commercial). Residential, commercial, and anything in between.

>> . The distributors don't even carry it.
>>
> I suppose it depends which distributors you use. Such connectors are
> hardly unknown in the USA.
> www.tnb.com/pubint/docs/snapnseal.pdf
>
> In the UK cable TV industry, for most applications, it would be a
> hanging offence not to use an approved Snap-N-Seal connector.

I didn't say they were unknown. Just that professional integrators
(including us) use better quality connectors.

And BTW, I checked with a couple of other integrator friends today.
They've never seen the cable companies around here use them, either. In
fact, the only place they've seen them used is by hobbyists and other
consumers. No professionals.

--
==================
Remove the "x" from my email address
Jerry Stuckle

jstu...@attglobal.net
==================

[Jerry Stuckle]

On 1/11/2014 11:33 AM, Jeff wrote:

> On 11/01/2014 14:12, Jerry Stuckle wrote:
>> On 1/11/2014 5:24 AM, Jeff wrote:
>>>
>>>>
>>>> As for handling more power - rubbish. The current in 75 ohm coax is
>>>> lower than that in 50 ohm coax, for the same power rating.
>>>>
>>>
>>> Can you not see the stupidity if that remark???
>>>
>>> Jeff
>>>
>>
>> It is perfectly true. P=I^2xR. As R increases, I MUST decrease to
>> handle the same power. And since current is the limiting factor in
>> wire, you don't need as large a gauge of wire to handle more power.
>>
>> You really should learn what you're talking about before opening your
>> "mouth". You only continue to show your ignorance.
>>
>

> Perhaps you should actually look at the theory of coax transmission
> lines. If you did you would find that the optimum impedance for max
> power handling peaks at about 30 ohms and falls away either side of that
> impedance, 50 ohms being better than 75 ohms. It is a little more
> complicated than just Ohms Law.
>
> It would appear that it is you who are showing their ignorance, and
> inability to even look at the article that was linked in post that you
> were replying to!!!
> <http://www.belden.com/blog/broadcastav/50-Ohms-The-Forgotten-Impedance.cfm>
>
>
> Jeff

Try again. I had it back in college in the early 70's (as an EE major),
and I don't think the laws of physics have changed.

And the best impedance for a coax is that which matches the input and
output impedance of the system, or if the input and output are of
different impedances, acts as a matching stub between the two.

And yes, I read the article. But you obviously don't understand it.
The 30 ohms they are talking about was for ONE SPECIFIC REQUIREMENT.
That does NOT mean it is true in different situations.

I suggest you learn what you're talking about before you make yourself
look even sillier.

[Jeff Liebermann]

On Sat, 11 Jan 2014 19:41:20 -0500, Jerry Stuckle
<jstu...@attglobal.net> wrote:

>I didn't say they were unknown. Just that professional integrators
>(including us) use better quality connectors.

Could I trouble you for a photo or part number for the crimp type F
connectors that you are using? I want to see what I'm missing.

Incidentally, SCTE IPS-TP-401 specifies that F connectors should
survive a 40 lb pull test.
<http://www.sbcatest.com/SBCA%20connector%20recommended%20practices.pdf>
I once built a fixture for testing this. Many of the cheap connectors
that I randomly purchased on eBay failed the test. You might want to
try it with your crimp connectors.

>And BTW, I checked with a couple of other integrator friends today.
>They've never seen the cable companies around here use them, either. In
>fact, the only place they've seen them used is by hobbyists and other
>consumers. No professionals.

Once a year, CED Magazine[1] provides an F-connector cross reference
wall chart. Here's the one for 2011. I don't recall seeing one in
the past 2 years probably because the incompatibility problems have
finally stabilized:
<http://www.cedmagazine.com/wallcharts/2011/10/f-connector-cross-reference-chart-2011>
<http://www.cedmagazine.com/sites/cedmagazine.com/files/Wall_Charts/1111_F-Cconnector-WC.pdf>
If you inspect the chart, you'll see the various SNS Snap-n-Seal part
numbers. The advertisement in the lower right is for Belden/T&B SNS
connectors.

What I guess(tm) happened was prior to Belden purchasing Thomas and
Betts in 2010, T&B had no interest in producing a connector that would
work with all RG-6/u type cables. Having many different types means
everyone has to carry a larger inventory. I'm too lazy to check, but
my bin contains at least 4 different F plugs for various manufacturers
cables and shield types of RG-6/u. I use the above chart to make sure
I don't create a mismatch. The most common connector is the SNS1P6
LRC series, color coded "blue", which fits double shielded RG-6/u.
<http://www.tnb.com/pubint/docs/snapnseal.pdf> (11 MBytes)
<http://www.youtube.com/watch?v=wBZAHhH4wCo> (2 min)
Immediately after the acquisition, Belden introduced the "red"
connector, which is a universal replacement for most of the others and
will fit double, triple, and quad shielded RG-6/u. My experience with
this connector hase been quite good. However, I continue to use the
"blue" for double shielded RG-6/u because I have about a years
inventory of connectors left. When I reorder, it will probably be the
universal (or ultimate) "red" type in cool looking nickel-tin plating.

Locally, Comcast and Charter both use various types of T&B
Snap-and-Seal connectors. I had Comcast install cable internet in our
office building. That's all that I saw in use. In older
installations, they use Augat LRC connectors, which are the
predecessor of the current Belden/T&B connectors.

You also mentioned compression and stripping tools. I have about 5 of
them, ranging from cheap eBay junk to the T&B IT1000 which sells for
about $100:
<http://www.mjsales.net/itemsearch.asp?FamilyID=202>
The IT1000 seems to work best, although some odd extra long
compression connectors, or the BNC or Phono compression connectors,
require a different tool. I also stupidly bought a compression tool
that only fits one manufacturers connectors, and none other. Most of
my ham antennas use a compression BNC connector and/or F-connector to
UHF or BNC adapter. My IT1000 is marked Augat LRC, which should give
a clue as to its age.

You also mentioned that you're using RG-59/u. Please note that
RG-59/u lacks the foil shield(s) of RG-6/u which means that it leaks
more and suffers from possible ingres problems. RG-59/u has higher
attenuation:
RG-59 RG-6
50 MHz 2.4 dB 1.5 dB
100 MHz 3.4 dB 2.0 dB
400 MHz 7.0 dB 4.3 dB
900 MHz 11.1 dB 6.8 dB
1000 MHz 12.0 dB 7.0 dB
I've purged RG-59/u from my life many years ago. Are you sure you
want to continue using the stuff.

Not all RG-6/u cables are equal. Here's some junk:
<http://sewelldirect.com/RG6-Bulk-Cable-Black-60-Braided-1000ft-Spool.asp>
RG-6/u with no foil shield and only 60% coverage.

[Jeff Liebermann]

On Fri, 10 Jan 2014 22:55:41 -0500, Jerry Stuckle
<jstu...@attglobal.net> wrote:

>That's theoretical. Reality is much different.

I think I'll print that on a large piece of paper and have it framed
for my office wall.

>Have you ever worked
>with a TDR? It's one of the tools we use regularly (and an expensive
>one, also).

Sure. Also OTDR for fiber. I don't use the expensive stuff, unless
you include the Acterna HST3000 tester that was stolen from my office
a few years ago. Mostly, I built my own using a pulse generator and
an oscilloscope.

You stated that the losses come primarily from the "impedance bump"
presumably produced by the non-50 ohm connector or adapter in the
line. Well, time to put that to the test.
1. Take a length of RG-6/u coax with good connectors. Apply signal
on one end from a generator. Measure the signal level on the other
end with a spectrum analyzer that has a 1dB per division scale. I
want to be able to see small changes.
2. After establishing a reference level, either beat on the coax
cable with a hammer, squash it with a C-clamp, or flatten it with a
bench vise. Squash it just enough to obtain an "impedance bump", but
not a short between the center conductor and shield. Note the change
in level, if you can see it.
3. Now, either un-squash the cable, or find another length of RG-6/u
and attach a TDR. It can be open, shorted, or terminated. Doesn't
matter.
4. Flatten the cable in the same manner as before and note the TDR
display.

What I expect that you'll see is that there will be almost no change
in attenuation, while the TDR display will show a rather radical
"impedance bump". That's because the only thing that the change in
impedance along the cable length can do is create reflections. Those
are a serious problem in a CATV system, but really don't involve
serious signal level losses.

That's theoretical. Reality is much the same.

>So? Dipoles aren't 50 ohm antennas. They're typically closer to 75 ohm.

I guess you missed my point. If you can tolerate the 1.5:1 VSWR, the
reduced attenuation and cost of 75 ohm coax makes the effort
worthwhile.

>As for handling more power - rubbish. The current in 75 ohm coax is
>lower than that in 50 ohm coax, for the same power rating.

Please re-read the article:
<www.belden.com/blog/broadcastav/50-Ohms-The-Forgotten-Impedance.cfm>
<http://www.microwaves101.com/encyclopedia/why50ohms.cfm>

>We use RG-59 where appropriate, like from an outlet to the set top box.
> But our in-wall coax runs are all RG-6 quad-shielded.

RG-59/u doesn't have a foil shield, so it's more flexible. So, I
guess that might work. For short lengths, the increased leakage,
higher ingress, and higher attenuation can probably be tolerated.
However, I use extra long RG-6/u, which somewhat compensates for the
lack of flexibility.

>But we're also doing less and less coax and more and more Category cable
>nowadays.

No MoCA installations?
<http://www.mocalliance.org>

>They're OK for the hobbyist, but I don't know of any professionals who
>use them. In fact, checking our main wholesalers, they aren't even
>available through them (but other Beldon products are).

Find a different distributor or ask for it by part number.
Thomas and Betts SNS1P6U.

Quick check: Stocked by Allied, Newark, Tessco, Farnel(UK), MCM.
Not stocked by Digikey, Mouser, Arrow.

T&B distributor search:
<http://www.tnb.com/ps/dls/dls?ca=corp>