Better Signal-to-Noise Ratio from a Combination of Improvements including . . . a Ground
RHF
Better Signal-to-Noise Ratio from a Combination of Improvements
including . . . a Ground.
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/5961
What I generally 'see' as far as an "Improvement" of the
quality of the RF Signal getting to the Receiver is from a combination
of things.
1. The Wire Antenna Element is placed farther from the House.
2. A 'remote' Ground Rod is used : Again this Ground Rod
is planted in the ground farther away from the House.
3. Use of a Matching Transformer between the Wire Antenna
Element and the Coax Cable : Mounted the Matching Transformer
on the Ground Rod - if possible.
4. Use of a Coax Cable Feed-in-Line : Laying-On -or-
Buried-Under the Ground - if possible.
5. The Extra Mile - Use a well grounded Lightning Arrestor
and/or an In-Line 1:1 Isolation Transformer where the Coax
Cable leaves the Ground and enters the House.
NOTE - All the above is no good if you do not have a very well
Grounded Household Electrical System. Do This First !
RESULTS - Actually in most instances what I 'see' is a reduction
in the S-Meter reading : But I also "Hear" a Greater Reduction
of the Noise Level. Thus the Signal-to-Noise Radio 'improves'
and the Listenability of the RF Signal (Audio) is much Better.
BUT REMEMBER - YOUR PRIMARY USE OF A GROUND IS FOR IMPROVED ELECTRICAL
SAFETY AND LIGHTNING PROTECTION - USE IT [.]
i hope we are communicating - iane ~ RHF
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= = = In Shortwave-...@yahoogroups.com,
= = = "David G******" <davidg******@c...> wrote:
JHR Wrote:
"...... I do not mean to contradict you, but my personal
experience with several radios yield the conclusion that
grounding at any point has no effect on receiving.......
....I just don't get it."
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DAVE Wrote:
Neither do I. My experience is the same.
I have never witnessed a signal improvement from the use
of a variety of different RF grounds. It think it's
possible that once or twice I think I heard a small
reduction in noise.
I suspect that my house electrical system provides
sufficient ground to yield the maximum differential
between what's on my antenna and ground.
~ Dave
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nm...@wt.net
For all and one...
>Better Signal-to-Noise Ratio from a Combination of Improvements
including . . . a Ground.
>http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/5961
What I generally 'see' as far as an "Improvement" of the
quality of the RF Signal getting to the Receiver is from a combination
of things.
>1. The Wire Antenna Element is placed farther from the House.
This can help if needed. Most of my antennas are over the house.
>2. A 'remote' Ground Rod is used : Again this Ground Rod
is planted in the ground farther away from the House.
But again, this is only due to the incomplete antenna that
you are running in that case. "I assume the usual random wire of
whatever config"
>3. Use of a Matching Transformer between the Wire Antenna
Element and the Coax Cable : Mounted the Matching Transformer
on the Ground Rod - if possible.
Again, this will almost always have zero effect on s/n ratio.
There is usually no lack of signal without the transformer.
>4. Use of a Coax Cable Feed-in-Line : Laying-On -or-
Buried-Under the Ground - if possible.
You do not have to use coax to have low noise reception.
Ladder line can work just as well, if properly balanced.
Coax is just often more convenient, and easier to work with.
But ladder line can be just as quiet. If the coax is poorly
decoupled, it will be as noisy as any unbalanced ladder line.
>5. The Extra Mile - Use a well grounded Lightning Arrestor
and/or an In-Line 1:1 Isolation Transformer where the Coax
Cable leaves the Ground and enters the House.
But what does this have to do with improving the s/n ratio?
>NOTE - All the above is no good if you do not have a very well
Grounded Household Electrical System. Do This First !
I'm sorry, but this is pure hogwash. You *do not* need *any*
kind of a ground to have a good low noise receiving system.
>RESULTS - Actually in most instances what I 'see' is a reduction
in the S-Meter reading : But I also "Hear" a Greater Reduction
of the Noise Level. Thus the Signal-to-Noise Radio 'improves'
and the Listenability of the RF Signal (Audio) is much Better.
Well, sure, you are decoupling the feedline in a better manner.
Ground wouldn't have anything to do with it, except you are using
ground as a method to decouple the feedline. You can decouple
the feedline just as well using other "non grounded" methods.
You are confusing a technique with the actual cure. The actual
cure is the decoupling of the line, not the ground. The ground is
just a method you are using to decouple the line.
>BUT REMEMBER - YOUR PRIMARY USE OF A GROUND IS FOR IMPROVED ELECTRICAL
SAFETY AND LIGHTNING PROTECTION - USE IT [.]
I have no argument with this if those concerns are actual.
IE: My battery run IC-706 needs no safety ground. In that
case, it can be ignored.
But my older tube rigs do need to be safety grounded.
In that case, ignoring can be painful... :(
Most of my antennas are elevated, and my mast does take
strikes from time to time. I *do* have a well grounded mast
for a lightning return, and I have a ground bulkhead outside
my window to ground lines to in bad wx...
But still....Has nothing to do with improving s/n ratio.. :/
>i hope we are communicating - iane ~ RHF
Your lips move, but I can't hear what you're sayin....
"optional Pink Floyd content" added as a bonus...
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= = = In Shortwave-SWL-Ante...@yahoogroups.com,
= = = "David G******" <davidg******@c...> wrote:
>JHR Wrote:
"...... I do not mean to contradict you, but my personal
experience with several radios yield the conclusion that
grounding at any point has no effect on receiving.......
I do mean to contradict him. He's full of BS, and many newbies
here will believe what he says is true. This is not good.
RHF seems like an enthusiastic sort, but I play no favorites,
or cut any slack, when I read blatant BS. I would expect the
same if I spewed BS, and anyone is welcome to debate my
theories on this subject. You will note that few challenge me on
this though. Why? Cuz I'm correct in this case concerning s/n
ratios, grounds, other related ad nausium.
In *most* cases it doesn't. It rarely improves a "complete"
antenna. I have seen grounding improve MW reception in some
cases, but rarely HF unless the antenna is lame... All my antennas
are complete, and adding a ground does nada...
>....I just don't get it."
Cuz, there's really nothing to get... :/
- - - - - - - - - - - - - - - - - - - - - - - - - - - -
>DAVE Wrote:
Neither do I. My experience is the same.
I have never witnessed a signal improvement from the use
of a variety of different RF grounds. It think it's
possible that once or twice I think I heard a small
>reduction in noise..............................................................................
Will usually be due to an improved decoupling of a line..
But ground is not required to complete this task.
>I suspect that my house electrical system provides
sufficient ground to yield the maximum differential
>between what's on my antenna and ground.
Best to use complete antennas. That way it won't matter..
Ground is actually a noise *source*. It's not the majic cure all...
Using ground as RHF describes is a bandaid decoupling
technique often used for an incomplete, fairly poorly designed,
antenna system. IE: the random wire....
MK
RHF
and 'your' Opinion is Welcome :o) ~ RHF
MK - Hey I guess you are right, 'we' should all
pack-up our long wire antennas and sell our radios.
Oops That's a - no, No. NO !
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nm...@wt.net
and 'your' Opinion is Welcome :o) ~ RHF
"With my best Elvis impersonation"
Thank ya, vury vury much...
MK - Hey I guess you are right, 'we' should all
pack-up our long wire antennas and sell our radios.
Oops That's a - no, No. NO !
No. Nothing wrong with using any type of antenna.
What is getting you into trouble is applying the technique
used with one particular type of antenna, and imply that it
applies to all. And also you are giving credit to the wrong thing
that improves the antenna you are using. It ain't the ground
in itself, or the transformer, which is almost never actually
needed. It's the decoupling of the feedline. The only reason
ground is mentioned is cuz it's the method used to help
decouple the feedline.
But still in the big picture, the random is fairly lame vs other
choices. It's just how far you want to go with it. If I had to
transmit using random wires, "which I have tried", I would
be miserable. Poor overall performance in general, and a
nightmare as far as rf problems in the shack, etc. Being I
already have full size dipoles for most of the HF bands, it
would be silly for me to use random wires for SWL.
And once you compare the two types, it's not too likely you
would want to use the random wire if you have room for
dipoles. I've also used full size HF ground planes. I often
run one for 40m, 36 ft at the base on a mast. The antenna is
nearly 70 ft tall. It is killer for long haul on the lower -mid HF
bands
late at night. On a path to Australia, that GP would beat my
dipole at 36 ft by appx 4 s units. Using that ground plane, and
1 KW of power I would always be over S 9 in Australia. Once got
a report of 20 db over 9 in Tokyo. That antenna browns the food.
And my dipole would probably beat the average random wire
by 4 s units. Then on the upper HF bands, I have a yagi.
Will hear stuff that wouldn't exist on many random wires due to
the forward gain, and f/b ratio. And it's steerable from the shack.
Use a random wire instead? Thanks, but no thanks.. :/
But I realize, not everyone is me... BTW, a random wire must be
at least one wavelength long on the band in use to qualify as a
"long wire". Pretty easy on the upper bands, but will need a pretty
long wire on the low bands. IE: 4 mhz will need appx 230-240 ft...
MK
Greg
> From: nm...@wt.net
> Organization: http://groups.google.com
> Newsgroups: rec.radio.shortwave
> Date: 22 Oct 2005 23:46:25 -0700
> Subject: Re: Better Signal-to-Noise Ratio from a Combination of Improvements
> including . . . a Ground
>
> MK - After all this is a NewsGroup
> and 'your' Opinion is Welcome :o) ~ RHF
>
> "With my best Elvis impersonation"
> Thank ya, vury vury much...
>
> MK - Hey I guess you are right, 'we' should all
> pack-up our long wire antennas and sell our radios.
> Oops That's a - no, No. NO !
>
> No. Nothing wrong with using any type of antenna.
> What is getting you into trouble is applying the technique
> used with one particular type of antenna, and imply that it
> applies to all. And also you are giving credit to the wrong thing
> that improves the antenna you are using. It ain't the ground
> in itself, or the transformer, which is almost never actually
> needed. It's the decoupling of the feedline. The only reason
> ground is mentioned is cuz it's the method used to help
> decouple the feedline.
>
(snip)
>
MK- Please elaborate. I am under the impression that:
1. A random-length "inverted L" wire antenna with coax lead-in is a good
choice for a simple, effective receive antenna for 1.8 to 30mHz listening.
2. That the matching transformer, with proper ground, is a simple,
practical, easy way to mitigate extraneous RF noise.
Is there a better single antenna that covers the HF spectrum? And what are
other ways to decouple the feedline?
Thanks,
Greg
nm...@wt.net
1. A random-length "inverted L" wire antenna with coax lead-in is a
good
choice for a simple, effective receive antenna for 1.8 to 30mHz
listening.
It's ok for general use. I'm not against random wires. Just RHF's
description of why or how they work...
2. That the matching transformer, with proper ground, is a simple,
practical, easy way to mitigate extraneous RF noise.
The matching transformer has nothing to do with it. The ground is
used as a method to help decouple the feedline. It's the decoupling
of the line that mitigates common mode currents. All the matching
transformer does is change impedance. But impedance/ SWR, etc,
have *nothing* at all to do with common mode currents flowing on
the shield. Nada. Zilch. The only reason people use the transformer
is to provide a better transfer of power. But it's almost always
overkill.
The use of one can pump up the S meter, but it rarely improves the
s/n ratio. In some cases, the transformer can actually degrade the
signal if the original match was better than the new one.
Is there a better single antenna that covers the HF spectrum? And what
are
other ways to decouple the feedline?
Dunno. Just depends on the needs, path, time of day, freq, etc, etc.
No one antenna is best for everything. Thats why I have several.
For general multiband use, I like paralleled dipoles fed with a single
coax.
A 1:1 balun or a coax choke at the feedpoint is used to decouple the
line.
Some like a dipole fed with ladder line and tuner. The dipole would be
cut for the lowest band to be used.
Some like a large loop fed in the same manner. There are a zillion
antennas that can be used. It depends on the antenna, etc, but with
most
systems, baluns or chokes are the most common decoupling devices.
With elevated ground planes, the radials help decouple the line, and
extra "decoupling radials, cones, sleeves, etc can be used.
With the random wires, grounding the shield, or chokes are commonly
used. But the use of ground as a decoupling aid is only used on
incomplete antennas like coax fed random wires, ground mount verticals,
etc.. You won't see that used on many "complete" antenna systems.
MK
Greg
> From: nm...@wt.net
> Organization: http://groups.google.com
> Newsgroups: rec.radio.shortwave
> Date: 23 Oct 2005 12:19:53 -0700
> Subject: Re: Better Signal-to-Noise Ratio from a Combination of Improvements
> including . . . a Ground
>
Okay, thanks. I'm starting to get the picture, though I'm not familiar with
the coax choke. I guess I'll do a little more googling.
Greg
RHF
(SWL) who simply has a 25-30 Foot Square Backyard ? ? ?
This same Broadcast Program SWL, who only can get their
Antenna Wire up about about 15-20 Feet High; and wants to
hear everything from 500 kHz thru 30 MHz ? ? ? ~ RHF
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nm...@wt.net
Dunno. I guess it's up to them, and how far they wanna go
with it. I can sit out in my truck and listen to anything from LW to
UHF. And it only takes up half a garage space worth of room. MK
I
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mi...@sushi.com
costs money, especially with the Bush weak dollar. I can tell by the
serial numbers that they don't sell many of these.
Actually, for 500Khz on the bottom end, you can use about 20ft of wire.
Note that getting the highest S reading really shouldn't be the goal.
Rather, you want the cleanest signal. After all, those vertical whips
with the JFET amp can get a high S reading, but the SNR isn't very
good.
RHF
Although the Horizontal Loop Antenna requires a little more work
then just a simple Longwire (Random Wire) Antenna or a low noise
Inverted "L" Antenna a la John Doty.
The Horizontal Loop Antenna does offer some advantages :
"IF" done as a beginning Shortwave Listeners (SWL) Antenna
that simply is designed to 'fit' into the backyard; or possibly
around the House under the Eaves; or fit the Loop inside the Attic.
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/6135
Such a Shortwave Listeners (SWL) Horizontal Loop Antenna
Can be built with common TV 'type' Parts that are available just
about anywhere and are relatively low cost.
Use 300 Ohm Twin Lead as the Wire Antenna Element and
wire the Two (2) Twin Wires in 'Series' to form a Double Loop
with two free ends to connect to the 300 Ohm Leads of the
Matching Transformer.
Note - Common 24 AWG Speaker Wire (Twin) can be used
for the Loop instead of Twin Lead if that is the only thing that
is available to build the Antenna.
Use a TV type 300 Ohm to 75 Ohm Matching Transformer
between the Loop Element and the Coax Cable Feed-in-Line.
Use RG6 Quad-Shield as a Feed-in-Line.
Use what ever available supports you can an try to get the
Loop Wire Antenna Element at least Ten Feet (10') in the
Air; with 15 to 20 Feet being better height above ground.
The Loop can be Round, Sort-of-Octagon, Square, Triangle,
as long as what goes 'around' comes back around to form
a complete 'Loop'.
The Loop Antenna being a so called 'Balanced' Antenna
does not require a Ground for its own operation.
NOTE - For Electrical Safety a "Ground" is REQUIRED for
the Radio Shack's Equipment.
JD - As you point out - Everyone has to start somewhere
and why not start with a Horizontal Loop Antenna for your
Shortwave Listening (SWL) enjoyment with your Radio/Receivers.
iane ~ RHF
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