PL-259 SO-239 connectors
Leland C. Scott
using a web structure, i.e. the dielectric is mostly air, to hold the center
conductor in place? I have seen this design used for mobile antenna mounts
for UHF antennas, and for coax connections used on V/UHF SWR - Watt Meters.
I don't know if these connectors are custom designs or are available as
stock items.
--
Leland C. Scott
KC8LDO
WB3KUM/9
use "N" connectors. They are not that expensive and may be cheaper the this
"custom" type of UHF connector.
Leland C. Scott
"WB3KUM/9" <bree...@NO.excite.SPAM.com> wrote in message
news:399AC912...@NO.excite.SPAM.com...
I know about "N" connectors, I have a few, and have installed them on some
LMR-400 cable. But, I am looking to upgrade a system without having to
switch everything over to "N" connectors, and the type of UHF connectors I
am looking for should perform almost as well as the "N" connectors at UHF.
That is if I can find any.
As far as the "N" connectors being cheap the best price I have found is
around $3 to $4 USD each for the male clamp type, at local Ham swaps. I
don't like the cheap solder "N" type connectors, had to get the metal too
hot to solder which started to melt the jacket on the ultrafelx LMR cable I
have.
--
73's,
Leland C. Scott
KC8LDO
ARRL member
NCI member
"You ask what Morse Code is good for? I'll tell you. Morse
Code is used exclusively by Electronics Based life forms to
communicate amongst themselves using advanced Organic
Digital Signal Processors, running state of the art Artificial
Intelligence Software, to perform the highly complex
transmit encryption, receive decryption and error correction
functions."
Dan Richardson
<bree...@NO.excite.SPAM.com> wrote:
>No, I have not. But if you are worried about loss or an impeadance hump, just
>use "N" connectors. They are not that expensive and may be cheaper the this
>"custom" type of UHF connector.
And after changing over to the "N"s I would bet the farm that no one
would know the difference if you didn't tell them.....
On the other hand you can have that warm fuzzy feeling that your
"lumps" are smaller.
73
Danny, K6MHE
Tom W8JI
<no-...@junk-mail.net> wrote:
>I know about "N" connectors, I have a few, and have installed them on some
>LMR-400 cable. But, I am looking to upgrade a system without having to
>switch everything over to "N" connectors, and the type of UHF connectors I
>am looking for should perform almost as well as the "N" connectors at UHF.
>That is if I can find any.
N connectors, below about 400 MHz, are a waste unless you have a whole
bunch of connectors in the line or are doing precision measurements.
They handle less power than a UHF connector, and are more difficult to
install and depend heavily on shield strength to stay put.
PL-259's aren't as waterproof, so you have to be careful, but they fit
the LMR400 cable without problem.
73 Tom
Morse code forever, communication when other systems let you down.
Leland C. Scott
"Tom W8JI" <2w...@contesting.com> wrote in message
news:399b95e...@news.akorn.net...
>
> N connectors, below about 400 MHz, are a waste unless you have a whole
> bunch of connectors in the line or are doing precision measurements.
As I have found out that all "depends" on two factors. The first is the type
of dielectric material used, and second the length of the connector. I did a
simple purely mathematical study of a 1 inch long SO-239 barrel connector,
with a PL-259 plug on each end, for an overall length of 1.25 inches, as a
test case. I have always heard the rule of thumb not to use UHF connectors
above the 2 meter band, and I wanted to find out why they are so "bad".
The data below was calculated based on the formulas I looked up to calculate
the Z of a coaxial conductor system, and the loss less transmission line
equation. All the calculations assume a pure load Z of 50 ohms connected to
one end of the barrel connector. The barrel connector, and plugs, are
treated as a transmission line with the length corrected for the frequency
used.
For a Teflon dielectric with a dielectric constant of 2.1 I get:
Zconnector=34.5 ohms
440 MHz; SWR=1.365
146 MHz; SWR=1.112
52 MHz; SWR=1.039
29 MHz; SWR=1.021
For the cheap Penolic dielectric with a dielectric constant of 4 I get:
Zconnector=25 ohms
440 MHz; SWR=2.241
146 MHz; SWR=1.335
52 MHz; SWR=1.109
29 MHz; SWR=1.06
And for the record with an Air dielectric constant of 4 I get:
Zconnector=50 ohms (Hum, very interesting!)
This would strongly suggest a UHF connector using mostly air should work
almost as well as a "constant Z" connector design. This would explain the
rib structure used to hold the center conductor in place on the high quality
SO-239 antenna mounts I have looked at, and the connectors on the back of
some V/UHF SWR-Watt meters too.
As you can see either dielectric type will give acceptable results on the 2
meter band, and below, with a perfect 50 ohm load. However on the 70 cm
band, unless you have a load close to 50 ohms, even the Teflon dielectric
may not work well, while the Penolic dielectric material is out of the
question. Both types of dielectric material appear to be OK for use on the 6
meter band and below. Remember that the above results are calculated for a
"Z bump" of 1.25 inches, a much longer connector, such as the long bulkhead
ones I have seen at Ham swaps, can cause SWR problems even at HF!
So like I said it all "depends", and using "N" connectors, or other
"constant Z" connectors, may not be such a dumb thing do, even below 400
MHz.
IMHO I guess it pays to go back and reexamine rules-of-thumb. Its amazing
what a little bit of investigation teaches one about how these
rules-of-thumb come about, and how to apply them in an intelligent manner.
Ham Radio, its a learning process for me as much as getting on the air and
yacking with other operators.
Tom W8JI
<no-...@junk-mail.net> wrote:
Good post. It's especially important to point virtually out all of the
"bump" occurs in the female part of the UHF connector. The male by
itself is fine when properly installed.
Females can be trouble at UHF, especially if you have a lot of them in
line.
>For the cheap Penolic dielectric with a dielectric constant of 4 I get:
>
>Zconnector=25 ohms
>
>440 MHz; SWR=2.241
>146 MHz; SWR=1.335
>52 MHz; SWR=1.109
>29 MHz; SWR=1.06
I've never seen a Penolic dielectric barrel connector, but of course
there are a large variety of connectors manufactured.
Barrel connector could indeed be a problem at UHF, if long enogh and
if the construction is poor enough. The could be a problem at VHF, if
the same poor quality applies and you use enough of them in the line.
>And for the record with an Air dielectric constant of 4 I get:
>
>Zconnector=50 ohms (Hum, very interesting!)
>
>This would strongly suggest a UHF connector using mostly air should work
>almost as well as a "constant Z" connector design. This would explain the
>rib structure used to hold the center conductor in place on the high quality
>SO-239 antenna mounts I have looked at, and the connectors on the back of
>some V/UHF SWR-Watt meters too.
A common trick, if you have a critical application, is to drill out
most of the dielectric in a standard connector. Pretty much needless
at lower frequencies, but in critical applications it can make a
difference at upper VHF and higher.
>As you can see either dielectric type will give acceptable results on the 2
>meter band, and below, with a perfect 50 ohm load. However on the 70 cm
>band, unless you have a load close to 50 ohms, even the Teflon dielectric
>may not work well, while the Penolic dielectric material is out of the
>question. Both types of dielectric material appear to be OK for use on the 6
>meter band and below. Remember that the above results are calculated for a
>"Z bump" of 1.25 inches, a much longer connector, such as the long bulkhead
>ones I have seen at Ham swaps, can cause SWR problems even at HF!
I've never seen that, and I use plenty of bulkhead connectors. It
would take almost a foot long female connector to cause a problem at
ten meters, or a bunch of shorter bumps placed at stratigic spots in
the line. Even so, the effect on loss would be low.
By far the biggest worry is some connectors, like those from Radio
Shack, overheat at high power levels (over 1000 watts) during extended
transmissions.
>So like I said it all "depends", and using "N" connectors, or other
>"constant Z" connectors, may not be such a dumb thing do, even below 400
>MHz.
Anyone using N connectors in QRO applications is asking for trouble.
Especially if SWR might ever get high.
People are often too concerned about SWR, and not enough about
comnponent reliability. An SWR of 1.5:1, especially if it is induced
near the rig end of the feedline, is meaningless in most applications.
The exception would be if the rig shuts down from the SWR, or if the
impedance goes "high" and unloads a fixed-tuned PA.
I think the perception SWR must be perfect comes from misuse of the
term "mismatch loss", or a lack of understanding of what SWR means and
how it affects the system.
73 Tom
Denis Sharon
> line.
Oh how true... and not just at UHF!
Denis Sharon W1AOK
Ridgefield, CT
Leland C. Scott
> I've never seen a Penolic dielectric barrel connector, but of course
> there are a large variety of connectors manufactured.
I have a few. Where I got them at I can't remember.
> A common trick, if you have a critical application, is to drill out
> most of the dielectric in a standard connector. Pretty much needless
> at lower frequencies, but in critical applications it can make a
> difference at upper VHF and higher.
Never heard of this being done. I will have to keep this one in my notes
files
>> Remember that the above results are calculated for a
> >"Z bump" of 1.25 inches, a much longer connector, such as the long
bulkhead
> >ones I have seen at Ham swaps, can cause SWR problems even at HF!
>
> I've never seen that, and I use plenty of bulkhead connectors. It
> would take almost a foot long female connector to cause a problem at
> ten meters, or a bunch of shorter bumps placed at stratigic spots in
> the line. Even so, the effect on loss would be low.
The ones I have seen are 2 to 3 inches long to as much as a foot and a
half!!
> By far the biggest worry is some connectors, like those from Radio
> Shack, overheat at high power levels (over 1000 watts) during extended
> transmissions.
The ones I see at my local Rat-Shack are made by Amphenol, and use Teflon
dielectric. These are a problem at high power levels?
> Anyone using N connectors in QRO applications is asking for trouble.
> Especially if SWR might ever get high.
I remember a thread, on this NG, some months back about how much power a "N"
connector can handle. I don't recall anyone ever finding a spec for a given
manufacture's connector.
Jim Jerzycke
500 Volts, peak.
No mention of power handling in the catalog.
Regards, Jim
Tom W8JI
Hi Jim,
I have no idea where or how those ratings were derived, but a
PL259/SO239 combo will handle a large amount more voltage and current
compared to a N. The N is dimensionally almost identical to a BNC as
far as conductor size and air gap in the connector.
I typically highpot all my jumpers before installing them, and just
last week highpotted a harness with N's and UHF fittings at opposite
ends. The N's were the voltage limiting connector, arcing between the
pin and the ground around the pin.
If you take the bayonet off a BNC male, it makes a dandy N-type quick
connect for the test bench.
On Thu, 17 Aug 2000 12:36:48 -0400, "Leland C. Scott"
<no-...@junk-mail.net> wrote:
>> By far the biggest worry is some connectors, like those from Radio
>> Shack, overheat at high power levels (over 1000 watts) during extended
>> transmissions.
>
>The ones I see at my local Rat-Shack are made by Amphenol, and use Teflon
>dielectric. These are a problem at high power levels?
The ones I am thinking of have a brownish plastic dielectric. They
swell up and stink at 1500 watts or less on RTTY or extended time on
CW.
>I remember a thread, on this NG, some months back about how much power a "N"
>connector can handle. I don't recall anyone ever finding a spec for a given
>manufacture's connector.
Into matched loads at HF, you'd be amazed at what cable and connector
can take what power. But any N has always been the weak link in my
systems. I take N females on my 7/8 Heliax and bore out the center and
shorten it. I add a center pin from a SO-239 with polyethelyne tubing
or PTFE tubing over the pin as an insulating sleeve. That gets rid of
the weak spots in case I accidentally hit the wrong antenna on the
wrong band at full power.
If I leave an N in line, it becomes toast. Generally on the furthest,
highest, hardest to reach connector in the middle of the rainy night
during a contest.
73 Tom
Leland C. Scott
> >> By far the biggest worry is some connectors, like those from Radio
> >> Shack, overheat at high power levels (over 1000 watts) during extended
> >> transmissions.
> >
> >The ones I see at my local Rat-Shack are made by Amphenol, and use Teflon
> >dielectric. These are a problem at high power levels?
>
> The ones I am thinking of have a brownish plastic dielectric. They
> swell up and stink at 1500 watts or less on RTTY or extended time on
> CW.
I think those are the ones with the Penolic dielectric. I have a few of them
too, kicking around in my junk box. I don't use them.
> Into matched loads at HF, you'd be amazed at what cable and connector
> can take what power. But any N has always been the weak link in my
> systems.
Somebody said, on this NG awhile back, that the DIN 7/16 inch connector
series was much better than "N" connectors for power handling.
> I take N females on my 7/8 Heliax and bore out the center and
> shorten it. I add a center pin from a SO-239 with polyethelyne tubing
> or PTFE tubing over the pin as an insulating sleeve. That gets rid of
> the weak spots in case I accidentally hit the wrong antenna on the
> wrong band at full power.
I have to think about this. I would have thought making this modification
would destroy the constant Z characteristic of the connector.
> If I leave an N in line, it becomes toast. Generally on the furthest,
> highest, hardest to reach connector in the middle of the rainy night
> during a contest.
Boo - Hiss!! Thats no fun!
Tom W8JI
<no-...@junk-mail.net> wrote:
>> The ones I am thinking of have a brownish plastic dielectric. They
>> swell up and stink at 1500 watts or less on RTTY or extended time on
>> CW.
>
>I think those are the ones with the Penolic dielectric. I have a few of them
>too, kicking around in my junk box. I don't use them.
No, it is plastic. I have no idea what kind of plastic, I suspect
maybe re-cycled Hefty trash bags that are still full of rottting
leaves.
It's the worse stuff I've even seen.
73 Tom
Roger Halstead
N833R World's Oldest Debonair? s# CD-2
"Tom W8JI" <2w...@contesting.com> wrote in message
news:399d85e5...@news.akorn.net...
> On Fri, 18 Aug 2000 08:24:28 -0400, "Leland C. Scott"
> <no-...@junk-mail.net> wrote:
>
> >> The ones I am thinking of have a brownish plastic dielectric. They
> >> swell up and stink at 1500 watts or less on RTTY or extended time on
> >> CW.
I bought some that appeared to have a teflon dielectric and silver plating,
The first time I tried to solder the center connector it "unrolled" into a
"U" shape instead of remaining a tube. I also had a devil of a time getting
solder to stick to it.
I've also run into the ones with the brown dielectric and that stuff starts
melting when you are working on the braid, let alone the center connector.
If either of those were Amphenol then they have come out with something less
than their usual quality. <:-))
> >
> >I think those are the ones with the Penolic dielectric. I have a few of
them
> >too, kicking around in my junk box. I don't use them.
>
> No, it is plastic. I have no idea what kind of plastic, I suspect
> maybe re-cycled Hefty trash bags that are still full of rottting
> leaves.
Nah, They just smell that way!
Roger (K8RI)
Terry Sanford
So 'N' connectors may be a problem at high powers?
Reason I ask is that I was thinking about using 'N' type at base of my sailboat
mast for marine VHF (max 25 watts) because it looked a lot more waterproof than
the PL-259/SO-239 type. Whatever type I'll probably put it in a heat shrink
sleeve anyway.
Any advice would be appreciated.
Terry S.
Tom W8JI
N connectors are fine at power levels below a kilowatt. They are, if
properly installed more water resistant than UHF fitting assuming both
are exposed to water through lack of external protection.
If you heatshrink connectors, use flooded heatshrink to seal the
connection. Otherwise you are better off with tape and a sealing
compound like "vapor wrap".
The only thing worse than not sealing a connection at all is....
sealing it so water leaks in and can't get out. As a matter of fact,
I'd use flooded cable in any marine installation along with flooded
heatshrink.
73 Tom
Jim Weir
shared these priceless pearls of wisdom:
-
->Reason I ask is that I was thinking about using 'N' type at base of my
sailboat
->mast for marine VHF (max 25 watts) because it looked a lot more waterproof
than
->the PL-259/SO-239 type.
N is way, way overkill. BNC is smaller, lighter, a hell of a lot easier to put
together, and comes in the right size for RG-58 cable, which is probably what
you will want to use at 150 MHz. and 25 watts.
If you want it REALLY, REALLY waterproof, squeeze some silicone seal onto the
connector, then shrink sleeve over that. Make sure that you shrink it from the
center out to the edges and that some silicone "bleeds" out the end of the
sleeving where it goes over the coax. It will take a knife and an afternoon to
ever get it apart again, but it is guaranteed waterproof for life.
Jim
Jim Weir, VP Eng. RST Eng. WX6RST
A&P, CFI, and other good alphabet soup
Dan K Nelson
news:askqpsgghidegb94l...@4ax.com...
> Terry Sanford <tsan...@roadrunner.nf.net>
> shared these priceless pearls of wisdom:
>
> -
> ->Reason I ask is that I was thinking about using 'N' type at base of my
> sailboat
> ->mast for marine VHF (max 25 watts) because it looked a lot more
waterproof
> than
> ->the PL-259/SO-239 type.
>
> N is way, way overkill. BNC is smaller, lighter, a hell of a lot easier
to put
> together, and comes in the right size for RG-58 cable, which is probably
what
> you will want to use at 150 MHz. and 25 watts.
RG-58 has about 5 db loss per 100 foot at 150 mhz. Even a 50 foot run will
result in a loss of about half of the power fed into it, as well as half of
the received signal strength. I would think that a 25 watt marine radio on
the open waters would opt for max range and reliability, therefore he would
probably want to use an LMR-400 or 9913 type cable to keep feedline losses
at a minimum. If so, a UHF or type N connector would be appropriate.
>
> If you want it REALLY, REALLY waterproof, squeeze some silicone seal onto
the
> connector, then shrink sleeve over that. Make sure that you shrink it
from the
> center out to the edges and that some silicone "bleeds" out the end of the
> sleeving where it goes over the coax. It will take a knife and an
afternoon to
> ever get it apart again, but it is guaranteed waterproof for life.
>
> Jim
> Jim Weir, VP Eng. RST Eng. WX6RST
> A&P, CFI, and other good alphabet soup
73 de W6DKN
Jim Weir
shared these priceless pearls of wisdom:
->
->RG-58 has about 5 db loss per 100 foot at 150 mhz. Even a 50 foot run will
->result in a loss of about half of the power fed into it, as well as half of
->the received signal strength. I would think that a 25 watt marine radio on
->the open waters would opt for max range and reliability, therefore he would
->probably want to use an LMR-400 or 9913 type cable to keep feedline losses
->at a minimum. If so, a UHF or type N connector would be appropriate.
Y'all ever actually DONE one of these installations before, sir, or spent a
dozen or so years in the industry?
When you have, please offer your "think" as opposed to standard practice.
Roger Halstead
N833R World's Oldest Debonair? s# CD-2
"Jim Weir" <j...@rst-engr.com> wrote in message
news:askqpsgghidegb94l...@4ax.com...
> Terry Sanford <tsan...@roadrunner.nf.net>
> shared these priceless pearls of wisdom:
>
> -
> ->Reason I ask is that I was thinking about using 'N' type at base of my
> sailboat
> ->mast for marine VHF (max 25 watts) because it looked a lot more
waterproof
> than
> ->the PL-259/SO-239 type.
>
> N is way, way overkill. BNC is smaller, lighter, a hell of a lot easier
to put
> together, and comes in the right size for RG-58 cable, which is probably
what
> you will want to use at 150 MHz. and 25 watts.
>
> If you want it REALLY, REALLY waterproof, squeeze some silicone seal onto
the
> connector, then shrink sleeve over that. Make sure that you shrink it
from the
> center out to the edges and that some silicone "bleeds" out the end of the
> sleeving where it goes over the coax. It will take a knife and an
afternoon to
> ever get it apart again, but it is guaranteed waterproof for life.
Couple of items.
If the silicon seal smells like acetic acid? It's the corosive stuff.
Don't put it in contained areas.
Where I used to work we purchased a whole bunch of transducers potted in the
stuff inside cast aluminum boxes.
About a year later they started going bad.
Sure enough, when we started takeing them apart we found that most of the
foil was gone from the boards. Well over $20,000 down the drain plus labor
which made the $20,000 look like chicken feed.
Get the stuff that "stinks", but not the black stinky stuff as it is
conductive.
I believe both GE and Dow Corning make the non conductive stuff as well as
the regular. I know DC does as I worked for them well over 30 years. That
is why I also know that if it smells like acetone it's corosive.
I use DC-4 compound and fill the connector, then like Jim, I head the shrink
tubing from the center out. Actually I do each end first, then move to the
center and work out and use a piece of tubing about five to six inches
long.
I have used the "bathtub calk" which is usually corosive and had it eat the
plating right off the connectors. (smelled like acetone)
Also, that stuff cures by moisture so if it cures inside the connector
within a few days you can be certain that the connector was not moisture
proof, or well sealed, heat shrink tube, or not. Then again, the silicon
rubber (such as Silastic RTV @) is water proof, but not moisture proof.
But...As I said, it is water proof and will keep salt out as well.
>
I've even used the bathtub calk to seal coax to dipoles and it turned green
where the stuff contacted the copper wire. Course out there and with heavy
wire it's not really a problem, but finer wires, solder, and foil in
contained spaces are bad news.
Roger (K8RI)
Ian White, G3SEK
>A question re 'N' versus PL-259 connectors; based on information posted here.
>
>So 'N' connectors may be a problem at high powers?
>
>sleeve anyway.
>
>Any advice would be appreciated.
No worries about power - problems begin at >1500W on 144MHz, or >1kW on
432. Even there, a lot of the problems are due to amateur assembly
techniques and recycled connectors. N connections that have no
imperfections and are left alone can be very reliable, even at these
high power levels.
It's true that N is much more waterproof than 259/239 (well, that's not
difficult) but I wouldn't trust a bare connector for marine use.
Equally, I wouldn't trust a heat shrink sleeve on its own. US hams can
advise you on the grades of Scotch/3M tape to use for multiple wrapping.
Having done all that, you might as well use 259/239.
One hint - try to avoid outdoor connections between a coax plug (any
type) and a flange socket on the side of a box. That's an almost
impossible shape to wrap with tape. Putty materials such as Coax-Seal
will work, but make a mess of the connectors. It's much better to
replace the fixed socket with a short length of coax coming out through
a proper waterproof cable gland, and terminate that coax in a line
jack. The jack + plug combination is a much easier shape to waterproof
with tape wraps.
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.com/g3sek
Dan K Nelson
> "Dan K Nelson" <w6...@qsl.net>
> shared these priceless pearls of wisdom:
>
> ->
will
> ->result in a loss of about half of the power fed into it, as well as half
of
> ->the received signal strength. I would think that a 25 watt marine radio
on
> ->the open waters would opt for max range and reliability, therefore he
would
> ->probably want to use an LMR-400 or 9913 type cable to keep feedline
losses
> ->at a minimum. If so, a UHF or type N connector would be appropriate.
>
> Y'all ever actually DONE one of these installations before, sir, or spent
a
> dozen or so years in the industry?
>
> When you have, please offer your "think" as opposed to standard practice.
>
> Jim Weir, VP Eng. RST Eng. WX6RST
> A&P, CFI, and other good alphabet soup
Pardon me for stating the facts, but the losses are real, and the
performance difference between RG-58 and LMR-400 at 150 mhz. is obvious. And
yes, I have installed several VHF radios, and I have measured the losses in
different types of feedlines. I may not have your "pedigree", but the
numbers don't lie. What do you want, max performance, or convenience of
installation? If "standard practice" is to use RG-58 for VHF installations,
then apparently the choice is for convenience of installation (unless you
are running a VERY short piece of feedline).
73 de W6DKN
(Sorry, no pedigrees, just common sense)
Tom W8JI
wrote:
>
>I've even used the bathtub calk to seal coax to dipoles and it turned green
>where the stuff contacted the copper wire. Course out there and with heavy
>wire it's not really a problem, but finer wires, solder, and foil in
>contained spaces are bad news.
You never ever want to use vulcanizing sealers on lines, use something
that stays gooey.
The best compounds are things like GE dielectric compound silicon or
the stuff made for CATV systems.
Use a bit sparingly inside the connector on the threads. Use a heat
shrink with goo imbedded in the shrink, like CATV companies use
outdoors and underground.
If you don't use that, use good tape and cover it with vapor wrap or
auto body seam sealer that stays flexable.
73 Tom
Dan Richardson
wrote:
>On Sat, 19 Aug 2000 03:17:44 GMT, "Roger Halstead" <rdha...@tm.net>
>wrote:
>
>>
>>I've even used the bathtub calk to seal coax to dipoles and it turned green
>>where the stuff contacted the copper wire. Course out there and with heavy
>>wire it's not really a problem, but finer wires, solder, and foil in
>>contained spaces are bad news.
>
>You never ever want to use vulcanizing sealers on lines, use something
>that stays gooey.
>
>The best compounds are things like GE dielectric compound silicon or
>the stuff made for CATV systems.
>
>Use a bit sparingly inside the connector on the threads. Use a heat
>shrink with goo imbedded in the shrink, like CATV companies use
>outdoors and underground.
>
>If you don't use that, use good tape and cover it with vapor wrap or
>auto body seam sealer that stays flexable.
>
>73 Tom
Tom,
Have you ever tried liquid electrical tape it's made by a Star brite
located in Ft Lauderdale, FL. I get it at the local hardware store and
it is the best stuff I have ever found for sealing coax connections &
etc.
Danny
Floyd Sense
describe. However, I've used the off-the-hardware-store-shelf variety of
silicone sealer (always the clear type) made by GE or Dow, for decades.
I've taken apart connections that were sealed with the stuff and have never
found anything but bright, clean, dry connections. Everything I've used
smells of acetic acid. I wonder if there isn't something else causing the
problem in some silicone compounds? I've never really used the stuff in an
enclosed area, so maybe the corrosive material bleeds out if the surface is
exposed to air and sunlight?
Usually, I wrap a connection tightly with vinyl electrical tape, then
silicone over that. However, connections I've made where the silicone was
in direct contact with PL-259 shells have never shown any effects from the
silicone.
K8AC
Floyd Sense - Angier, NC
Jim Weir
shared these priceless pearls of wisdom:
->Pardon me for stating the facts, but the losses are real, and the
->performance difference between RG-58 and LMR-400 at 150 mhz. is obvious.
Christ. Another theory ivory tower geek.
Run RG-58 and use BNC connectors like all the rest of the fleet uses. Use clear
silicone seal (even if it smells like vinegar) on the connectors, shrink
sleeving over the connectors and the goop, and enjoy your boat.
Gray Frierson Haertig
A 3 db loss of signal in VHF FM communications systems is generally not
noticeable and considered acceptable - it is swamped out by the spatial
and temporal variability of the signal that is inherent in VHF (and UHF)
propagation. Many commercial systems actually have much higher loss.
In most marine environments the most important design criterion is
robustness and reliability. For relatively short and well protected
runs RG-58 works fine. I would avoid cables with air dielectric like
9913 because of their susceptibility to flooding if the connector
weatherproofing fails or the outer jacket gets punctured. A closed cell
foam or polyethylene dielectric allows for the possibility of emergency
repair if a connector gets waterlogged.
If solid outer conductor cables (such as Heliax) are used, a good deal
of caution needs to be exercised in mechanical installation to prevent
repeated flexure. These cables will eventually work harden and break.
As to connector weatherproofing, I have started using the 3M cold shrink
products. They are a snap to install, easy to remove, don't leave a
gummy mess on the connector, and can be installed over a wide
temperature range. They aren't cheap, however. So far I have not had
any failures. They are widely used in direct bury electrical splices.
One antenna manufacturer recommends flooding outdoor Type N connectors
with petroleum jelly before connecting. I admit this makes me a bit
nervous, but I haven't seen any failures yet in installations up to 250
watts VHF after several years. It's an interesting idea. Does anyone
else have any experience with this?
Gray
>
> "Dan K Nelson" <w6...@qsl.net>
> shared these priceless pearls of wisdom:
>
> ->
> ->RG-58 has about 5 db loss per 100 foot at 150 mhz. Even a 50 foot run will
> ->result in a loss of about half of the power fed into it, as well as half of
> ->the received signal strength. I would think that a 25 watt marine radio on
> ->the open waters would opt for max range and reliability, therefore he would
> ->probably want to use an LMR-400 or 9913 type cable to keep feedline losses
> ->at a minimum. If so, a UHF or type N connector would be appropriate.
--
Telecommunications Engineering
Gray Frierson Haertig & Assoc.
820 North River Street, Suite 100
Portland, Oregon 97227
503-282-2989
503-282-3181 FAX
g...@haertig.com
TyllEulenspiegel
>"Tom W8JI" <2w...@contesting.com> wrote in message
>news:399b95e...@news.akorn.net...
>>
>> N connectors, below about 400 MHz, are a waste unless you have a whole
>> bunch of connectors in the line or are doing precision measurements.
>
>As I have found out that all "depends" on two factors. The first is the type
>of dielectric material used, and second the length of the connector. I did a
>simple purely mathematical study of a 1 inch long SO-239 barrel connector,
>with a PL-259 plug on each end, for an overall length of 1.25 inches, as a
>test case. I have always heard the rule of thumb not to use UHF connectors
>above the 2 meter band, and I wanted to find out why they are so "bad".
>
>The data below was calculated based on the formulas I looked up to calculate
>the Z of a coaxial conductor system, and the loss less transmission line
>equation. All the calculations assume a pure load Z of 50 ohms connected to
>one end of the barrel connector. The barrel connector, and plugs, are
>treated as a transmission line with the length corrected for the frequency
>used.
>
>For a Teflon dielectric with a dielectric constant of 2.1 I get:
>
>Zconnector=34.5 ohms
>
>440 MHz; SWR=1.365
>146 MHz; SWR=1.112
>52 MHz; SWR=1.039
>29 MHz; SWR=1.021
>
>For the cheap Penolic dielectric with a dielectric constant of 4 I get:
>
>Zconnector=25 ohms
>
>440 MHz; SWR=2.241
>146 MHz; SWR=1.335
>52 MHz; SWR=1.109
>29 MHz; SWR=1.06
>
>And for the record with an Air dielectric constant of 4 I get:
>
>Zconnector=50 ohms (Hum, very interesting!)
>
>This would strongly suggest a UHF connector using mostly air should work
>almost as well as a "constant Z" connector design. This would explain the
>rib structure used to hold the center conductor in place on the high quality
>SO-239 antenna mounts I have looked at, and the connectors on the back of
>some V/UHF SWR-Watt meters too.
>
>As you can see either dielectric type will give acceptable results on the 2
>meter band, and below, with a perfect 50 ohm load. However on the 70 cm
>band, unless you have a load close to 50 ohms, even the Teflon dielectric
>may not work well, while the Penolic dielectric material is out of the
>question. Both types of dielectric material appear to be OK for use on the 6
>meter band and below. Remember that the above results are calculated for a
>"Z bump" of 1.25 inches, a much longer connector, such as the long bulkhead
>ones I have seen at Ham swaps, can cause SWR problems even at HF!
>
>So like I said it all "depends", and using "N" connectors, or other
>"constant Z" connectors, may not be such a dumb thing do, even below 400
>MHz.
>
>IMHO I guess it pays to go back and reexamine rules-of-thumb. Its amazing
>what a little bit of investigation teaches one about how these
>rules-of-thumb come about, and how to apply them in an intelligent manner.
>Ham Radio, its a learning process for me as much as getting on the air and
>yacking with other operators.
>
Roy Lewallen
>
> I have no doubt that many of you have experienced the corrosive effects you
> describe. However, I've used the off-the-hardware-store-shelf variety of
> silicone sealer (always the clear type) made by GE or Dow, for decades.
> I've taken apart connections that were sealed with the stuff and have never
That's been my experience also.
Roy Lewallen, W7EL
Jim Weir
shared these priceless pearls of wisdom:
->One antenna manufacturer recommends flooding outdoor Type N connectors
->with petroleum jelly before connecting. I admit this makes me a bit
->nervous, but I haven't seen any failures yet in installations up to 250
->watts VHF after several years. It's an interesting idea. Does anyone
->else have any experience with this?
Yes. We used to use flooded Vaseline connectors with plain old sleeving tied
with wax cable back in "the old days" before shrink and silicone. Other than a
freakin' mess if you ever had to work on them after mating, they worked just
fine and lasted forever. This was in the 120 MHz. range with powers of 25 to
100 watts.
Bill Turner
>Use clear
>silicone seal (even if it smells like vinegar) on the connectors, shrink
>sleeving over the connectors and the goop, and enjoy your boat.
______________________________________________________________
There's a type of silicon seal that doesn't smell like vinegar and
which is totally waterproof - it's used to assemble aquariums. Get it
at any pet shop. The "vinegar" smell is acetic acid - nasty stuff
around metal. Best not to use it.
73, Bill W7TI
Leland C. Scott
"Leland C. Scott" <no-...@junk-mail.net> wrote in message
news:spno5j5...@corp.supernews.com...
Oops, just for the record I noticed I made a typo! The dielectric constant
of air should have been equal to 1.0. The numbers calculated however are
correct.
> And for the record with an Air dielectric constant of 4 I get:
--
Leland C. Scott
KC8LDO
Floyd Sense
the brand name) that is supposedly used in the cable TV industry. You fill
up the PL-259 shell with the stuff from a squeeze tube, and then screw the
connector together. It fills all the voids and even seals the thread.
Haven't taken any of the joints apart yet, so don't know how it holds up
over time.
--
Floyd Sense - Angier, NC
"Jim Weir" <j...@rst-engr.com> wrote in message
news:fiqups4bpncrjjfre...@4ax.com...
Dan Richardson
<sen...@sprintmail.com> wrote:
>I'm currently sealing connectors with a Teflon foam (sold by AES - forgot
>the brand name) that is supposedly used in the cable TV industry. You fill
>up the PL-259 shell with the stuff from a squeeze tube, and then screw the
>connector together. It fills all the voids and even seals the thread.
>Haven't taken any of the joints apart yet, so don't know how it holds up
>over time.
Yes, but don't try it on 9913!
Danny
ZZZjim...@juno.comzzz
Wrap with rubber tape. Use some tension and overlap.
Wrap that mess with Scotch (3M) electrical tape.
I recently took down an antenna that was up 3 years and
the connectors were still shiny.
73,
Jim
N2VNO
On Sat, 19 Aug 2000 03:17:44 GMT, "Roger Halstead" <rdha...@tm.net>
wrote:
>Roger Halstead (K8RI) www.RogerHalstead.com
Tom W8JI
wrote:
>
>Yes, but don't try it on 9913!
>
>Danny
Why Danny?
Dan Richardson
wrote:
>On Tue, 22 Aug 2000 23:37:39 GMT, k6...@arrl.net (Dan Richardson)
Hi Tom,
I think you will find that it dribbles down inside the 9913 and is no
longer sealing *by flooding* anything. The flooded area of the
connector is no longer flooded and the whole thing is a bummer.....
Danny
Tom W8JI
wrote:
.
>I think you will find that it dribbles down inside the 9913 and is no
>longer sealing *by flooding* anything. The flooded area of the
>connector is no longer flooded and the whole thing is a bummer.....
>
>Danny
Ohh, that hollow cable.
I never use that, because water dribbles out of it after a period of
time. During the daytime, it get heated. At night, no matter how I
seal it, it sucks humid air in. The next day the heat pushes the air
out but not the water.
I imagine it would suck the flooding compond in also.
73 Tom
Joe
then wrap with vinyl electrical tape, then apply a coat of 3M Scotchkote(TM).
When done right, I know that the connectors would be bright and clean after
one year since this was the maintenance interval on the antennas on ship. I
don't think that many hams have the seaborne enviroment that exist on a
naval ship.
ZZZjim...@juno.comZZZ wrote:
> A local fellow tuned me in on how to waterproof connectors:
>
> Wrap with rubber tape. Use some tension and overlap.
> Wrap that mess with Scotch (3M) electrical tape.
>
> I recently took down an antenna that was up 3 years and
> the connectors were still shiny.
>
> 73,
> Jim
> N2VNO
>
> On Sat, 19 Aug 2000 03:17:44 GMT, "Roger Halstead" <rdha...@tm.net>
> wrote:
>
> >Roger Halstead (K8RI) www.RogerHalstead.com
> >>
Roger Halstead
--
Roger Halstead (K8RI) www.RogerHalstead.com
N833R World's Oldest Debonair? s# CD-2
"Tom W8JI" <2w...@contesting.com> wrote in message
news:39a3a32...@news.akorn.net...
> On Wed, 23 Aug 2000 02:39:12 GMT, k6...@arrl.net (Dan Richardson)
> wrote:
> .
> >I think you will find that it dribbles down inside the 9913 and is no
> >longer sealing *by flooding* anything. The flooded area of the
> >connector is no longer flooded and the whole thing is a bummer.....
> >
> >Danny
>
> Ohh, that hollow cable.
>
> I never use that, because water dribbles out of it after a period of
> time. During the daytime, it get heated. At night, no matter how I
> seal it, it sucks humid air in. The next day the heat pushes the air
> out but not the water.
>
> I imagine it would suck the flooding compond in also.
>
Only seal the one end. Course that doesn't help much when you have multiple
connectors outside.
Roger (K8RI)
> 73 Tom
Tom W8JI
wrote:
>Only seal the one end. Course that doesn't help much when you have multiple
>connectors outside.
>
>Roger (K8RI)
I only use it on vertical runs Roger, and I poke a hole in the bottom
of the drip loop so it can drain. I'm slowly replacing it all now.
73 Tom
Gary V. Deutschmann, Sr.
Interesting, we used to use ScotchKote as well, but it was not
flexible, it was like a very hard pea green color thick 2 part enamel.
TTUL
Gary
Roger Halstead
N833R World's Oldest Debonair? s# CD-2
"Tom W8JI" <2w...@contesting.com> wrote in message
news:39a40a8d...@news.akorn.net...
What do you use for coax tom?
I have to basically replace all mine as the new runs are longer than the
current ones (over all about 175 to 200 feet from rig to antennas).
I'm thinking about using the new Times Wire coax for the VHF and UHF
antennas.
73
Roger (K8RI)
>
> 73 Tom
Tom W8JI
wrote:
>What do you use for coax tom?
>I have to basically replace all mine as the new runs are longer than the
>current ones (over all about 175 to 200 feet from rig to antennas).
I use a variety of stuff, depending on what's the most important
concern for that run.
The only thing I'm getting rid of is the hollow core cables, because
of moisture buildup. I actually never would have used any in the first
place, if I didn't get 1000 feet along with a tower and antenna I
bought from an estate.
73 Tom
Gary Coffman
>Amphenol rates their type-N at 1500 Volts, peak, and their type-UHF at
>500 Volts, peak.
>No mention of power handling in the catalog.
>Regards, Jim
I don't think those numbers are correct. Type N should be the same as BNC,
because the connecting surfaces are the same size (IE pin and shield ring)
and spacing. BNC is rated to 500 volts. 500 volts is 5 kW in a 50 ohm system
(P=E^2/R).
I know that N connectors will handle 5 kW PEP, because that's the power level
of the driver stage in our older TV transmitter, and it uses N connectors for the
semi-rigid line which couples it to the PA. It has been working for better than 20
years with no connector failures.
OTOH, type UHF connectors have been used by amateurs as HV connectors
(not a good practice, but done anyway), at voltages up to 8 kV. So a rating of
only 500 volts doesn't look right for them. The type UHF has a larger spacing
than the type N and BNC, so it only seems reasonable that it would have a
higher voltage rating too.
Gary
Gary Coffman KE4ZV | You make it |mail to ke...@bellsouth.net
534 Shannon Way | We break it |
Lawrenceville, GA | Guaranteed |
Tom W8JI
wrote:
>On Thu, 17 Aug 2000 19:52:12 +0000, Jim Jerzycke <kq...@amsat.org> wrote:
>>Amphenol rates their type-N at 1500 Volts, peak, and their type-UHF at
>>500 Volts, peak.
>>No mention of power handling in the catalog.
>>Regards, Jim
>
>I don't think those numbers are correct.
>OTOH, type UHF connectors have been used by amateurs as HV connectors
>(not a good practice, but done anyway), at voltages up to 8 kV. So a rating of
>only 500 volts doesn't look right for them. The type UHF has a larger spacing
>than the type N and BNC, so it only seems reasonable that it would have a
>higher voltage rating too.
>
>Gary
I agree with Gary, except for the voltage issue. Most catalogs I've
seen give a peak voltage breakdown, not RMS. 500 volts peak is 354
volts RMS, and that's 2500 watts peak or average power.
Most connectors are conservatively rated, and in a comntrolled
environment with a quality connector I'm not surprized to see an N
hadle 5 kW peak if average power is low and SWR is unity.
When dealing with arcing, peak and average power ratings are the same.
We should use RMS voltage only when heat is the concern, not arcing,
unless the component also uses RMS volage for the same waveshape.
Since component manufacturers can't control waveshape, they almost
always use peak voltage in ratings.
Despite the catalog numbers quoted, UHF connector fail at
considerably more voltage than N or BNC connectors....both of which
have about the same peak voltage flashover point.
The center pins in BNC and N's are almost identical, as are spacings.
The N connector and BNC connector have two weak areas compared to a
UHF connector. The UHF connector has much higher current handling
capacity and much higher voltage breakdown. I'd never use an N
connector in a high power (more than 1000 watts average) system unless
absolutely necessary for SWR reasons. At somewhere over 100 or 200 MHz
or for exceptionally critical applications , N connectors do have an
SWR advantage.
73 Tom
Dino
The SO 239/PL 259 combo is good up to about 400MHz. It was originally
a military connector and became standard for Amateur Radio and CB.
This connecotr's impeadence CHANGES with frequency though!
All of you HF frequencies are unaffected (basically) from this
connector. This includes CB too. They are easy to install and work
well UNTIL you get to higher frequencies.
The N-Connector on the other hand has a CONSTANT IMPEDANCE up to the
Gigahertz range. You buy either a 50 ohm or 75 ohm connector. The
N-Connecotr also has a gasket to seal out water/moisture! It is clearly
a superior connector but is a little harder to install.
If I remember right, the UHF (SO 239/PL 259) connector can handle more
power (watts) but don't quote me on this.
The BNC is a "Bayonet N-Connector" and also has a CONSTANT IMPEDANCE
but lacks the seal.
I have converted most of my equipment to either BNC or N ancluding my
antennas. The better antenna companies offer N-connectors on their
HF antennas.
Yaesu and Kenwood produced radios that used N-Connectors for 440MHz and
above for a reason. Remeber the UHF connector is only good to 400MHZ and
does NOT garrantee a constant impedance! This causes a mis-match resulting
in higher SWR. Its like having a 75 ohm feedline hooked to a 50 ohm
feedpoint.
Now to answer your question...
You find quality connectors on quality cable. You buy the better cable for a
reason! Why ruin that with a substandard connector. Do it right the first
time. Besides, why would you want a higher SWR even befor you hook it to the
antenna due to cable/connector mis-match.
Most HF stations do NOT run Heliax. You find these on long runs and VHF and
above. Especially repeaters where you want a CONSTANT IMPEDANCE in your
feedline and antenna.
For HF, regular coax and a UHF connector is fine.
Dino...K6RIX
>Ok, then I'm curious...
>Why is it that UHF connectors are not standard on real thick cables like
>Andrews 1/2" and up? I see that N type is standard when using heliax and
>thicker cables up to a point.
Dale Parfitt
Dino wrote:
The BNC is a "Bayonet N-Connector" and also has a CONSTANT IMPEDANCE
>
>
The bayonet part is right for the B, but the NC stands for the developers from
Bell Labs= Neill and Concelman
Dale W4OP