In article ,
(Mark Keith) wrote:

Dave wrote in message
. ..
Balderdash. A transformer that correctly drives the co-ax is a
great advantage.

Depends on the radio. Very few modern radios would benefit as far as
s/n ratio. All the transformer usually does is pump up the s meter.
If when hooking up the antenna, the noise level increases, you have
enough signal. Increasing the level does not increase the s/n ratio
unless the radio is half dead. On the lower frequencies, you have so
much signal level with any decent length wire, you could drastically
reduce it, and still have plenty.

On Mon, 07 Jul 2003 11:20:47 -0600, JJ
wrote:



Vince Fiscus, KB7ADL wrote:

There is no real advantage
for a balun on an antenna just for receiving.

Well, there is in some cases. In cases of bad shack noise, you can
drastically reduce noise ingress by adding a good balun or choke.
Also, many directional antennas like yagi's need decoupling for an
accurate pattern. Feedline radiation will skew the pattern. Also with
verticals used for VHF/UHF, decoupling is critical for good low angle
performance. Being all is reciprical, it's as important to receive as
it is to transmit. But, I do agree, as far as s/n ratio is concerned
with an HF wire antenna, a balun or transformer is not generally
needed. If adding matching actually improves the s/n ratio, you
likely have a fairly lame radio. The bigger payoff is reduced noise
ingress from the shack. That will improve the s/n ratio. If you
actually have noise that is... MK


I don¹t understand this kind of thinking that you should not derive the
maximum benefit of an antenna that one has gone through the trouble to
put up. Your logic of all the transformer is good for is pumping up the
S meter falls flat when you don¹t have enough signal for full quieting
or whether you can make out the program material at all if the signal is
very weak. I don¹t see the need to call anyone¹s radio lame either.

Most antennas output impedance is nowhere near the typical 50-ohm coax
and a transformation can remedy that. In addition there are advantages
to preventing the coax interacting with the antenna some of which you
stated above.

Some antenna designs are better at rejecting local noise than others.
They only work if coupled properly to the coax resulting in better
signal to noise.

--
Telamon
Ventura, California

Telamon wrote in message


I don¹t understand this kind of thinking that you should not derive the
maximum benefit of an antenna that one has gone through the trouble to
put up. Your logic of all the transformer is good for is pumping up the
S meter falls flat when you don¹t have enough signal for full quieting
or whether you can make out the program material at all if the signal is
very weak. I don¹t see the need to call anyone¹s radio lame either.

If you are using a 70 ft random wire on HF, and you don't have enough
signal level to have a usable s/n ratio on any HF freq, you would have
a lame radio. Thats just the simple facts. Nothing personal... This is
2003. Radios are not half dead on the upper bands like to used to be
50 years ago, unless they are toys or out of alignment. There is no
"full quieting" unless you are on FM. That would generally be 10m up.
I'll repeat it again. If you hook up your antenna, and the background
noise level increases, even if just a little, you have all the s/n
ratio you need. Increasing the signal level beyond that point will not
increase the s/n ratio. It only pumps up the S meter. To see an
improvement in copy , you would need to use a directive antenna. Any
noise along with the desired signal has also increased in proportion,
so your actual s/n ratio is the same.
Sure, the signal may sound "louder" with the higher S meter reading,
but thats mainly because the level is higher, and due to the
limitations of the filter, the signal seems "wider". But the
selectivity has slightly decreased.

Most antennas output impedance is nowhere near the typical 50-ohm coax
and a transformation can remedy that.

But it doesn't matter. You don't have enough loss with the mismatch to
worry about with any decent radio. It's just not enough to knock you
out of the water. I did the math on this a few months ago, and posted
here to demonstrate this. This has been debated before many times. I
used coax feed with wild feedpoint impedances just to ensure a worst
case as far as feeder loss. It doesn't amount to enough to hurt you.
If it does, you have a lame radio. If you used a random wire direct
with no feeder, there is even less loss. For receiving, the mismatch
in that case doesn't matter enough to worry about at all.

In addition there are advantages
to preventing the coax interacting with the antenna some of which you
stated above.

Some antenna designs are better at rejecting local noise than others.
They only work if coupled properly to the coax resulting in better
signal to noise.

Sure, but that has nothing to do with the impedance tranformation. I
have no problems if people want to use transformers, I'm just saying
it's an option and should not really be needed as far as s/n ratio is
concerned. I don't use a tuner or matching on my wire antenna no
matter what freq I go to. I don't need to. I don't even come close to
needing it. I have plenty of signal level on any freq. Any doubt's and
you can pick a freq, and I'll record it and post as an mpeg.
I can dial up 28 mhz at 3 AM, and have plenty of background noise. If
I switch to the dummy load, all goes dead. Actually, I bet I could do
it at 150 mhz also...Sure, I can add my MFJ-989c tuner, and get a
perfect match as far as my radio is concerned, and maybe even pump up
the noise level an s unit or two. But it doesn't increase my s/n ratio
one whit.
BTW, any radio can be a "lame" radio, if it's not working right. I've
had a few of mine cramp up through the years. MK

In article ,
(Mark Keith) wrote:

Telamon wrote in message

I don¹t understand this kind of thinking that you should not derive the
maximum benefit of an antenna that one has gone through the trouble to
put up. Your logic of all the transformer is good for is pumping up the
S meter falls flat when you don¹t have enough signal for full quieting
or whether you can make out the program material at all if the signal is
very weak. I don¹t see the need to call anyone¹s radio lame either.

If you are using a 70 ft random wire on HF, and you don't have enough
signal level to have a usable s/n ratio on any HF freq, you would
have a lame radio. Thats just the simple facts. Nothing personal...
This is 2003. Radios are not half dead on the upper bands like to
used to be 50 years ago, unless they are toys or out of alignment.
There is no "full quieting" unless you are on FM. That would
generally be 10m up. I'll repeat it again. If you hook up your
antenna, and the background noise level increases, even if just a
little, you have all the s/n ratio you need. Increasing the signal
level beyond that point will not increase the s/n ratio. It only
pumps up the S meter. To see an improvement in copy , you would need
to use a directive antenna. Any noise along with the desired signal
has also increased in proportion, so your actual s/n ratio is the
same. Sure, the signal may sound "louder" with the higher S meter
reading, but thats mainly because the level is higher, and due to the
limitations of the filter, the signal seems "wider". But the
selectivity has slightly decreased.

The signal will not sound louder with a higher S meter reading if you
are using a radio with AGC on and it¹s working right.

Sorry to use a miss leading term ³full quieting.² I did not mean to
refer to FM modulation. Let me explain that I live in town and have
local noise to compete with any signal I pick up. This noise must be
overcome so I only hear the program material of interest. In other words
the volume can be turned up so the program material is very loud without
any background noise or hiss. Antenna efficiency that generates more
signal energy overcomes the local noise sources. You must be unusually
lucky to live in a location where all you pick up is either broadcast
signal or atmospheric noise. I don¹t think most people are as fortunate.

Most antennas output impedance is nowhere near the typical 50-ohm coax
and a transformation can remedy that.

But it doesn't matter. You don't have enough loss with the mismatch to
worry about with any decent radio. It's just not enough to knock you
out of the water. I did the math on this a few months ago, and posted
here to demonstrate this. This has been debated before many times. I
used coax feed with wild feedpoint impedances just to ensure a worst
case as far as feeder loss. It doesn't amount to enough to hurt you.
If it does, you have a lame radio. If you used a random wire direct
with no feeder, there is even less loss. For receiving, the mismatch
in that case doesn't matter enough to worry about at all.

Well OK I guess my radios are lame or busted. I must be imagining things
when signals go from ³I can just make it out S1² to ³easy to listen to
S3² on the folded dipole with the transformer. My other loop antennas
must not be working right either.

In addition there are advantages to preventing the coax interacting
with the antenna some of which you stated above.

Some antenna designs are better at rejecting local noise than
others. They only work if coupled properly to the coax resulting in
better signal to noise.

Sure, but that has nothing to do with the impedance tranformation. I
have no problems if people want to use transformers, I'm just saying
it's an option and should not really be needed as far as s/n ratio is
concerned. I don't use a tuner or matching on my wire antenna no
matter what freq I go to. I don't need to. I don't even come close to
needing it. I have plenty of signal level on any freq. Any doubt's
and you can pick a freq, and I'll record it and post as an mpeg. I
can dial up 28 mhz at 3 AM, and have plenty of background noise. If I
switch to the dummy load, all goes dead. Actually, I bet I could do
it at 150 mhz also...Sure, I can add my MFJ-989c tuner, and get a
perfect match as far as my radio is concerned, and maybe even pump up
the noise level an s unit or two. But it doesn't increase my s/n
ratio one whit. BTW, any radio can be a "lame" radio, if it's not
working right. I've had a few of mine cramp up through the years.

I¹ll see about getting my radios fixed.

--
Telamon
Ventura, California

Telamon wrote in message ..
Let me explain that I live in town and have
local noise to compete with any signal I pick up. This noise must be
overcome so I only hear the program material of interest. In other words
the volume can be turned up so the program material is very loud without
any background noise or hiss. Antenna efficiency that generates more
signal energy overcomes the local noise sources. You must be unusually
lucky to live in a location where all you pick up is either broadcast
signal or atmospheric noise. I don¹t think most people are as fortunate.

I assume your noise must be shack generated, and is an ingress
problem. I would think anyway. If the noise was local, but picked up
from the antenna itself
along with the desired station, then adding the transformer would not
change the s/n ratio. The noise would increase along with the station
at an equal rate. Everything would "sound" the same. Only the S meter
would read higher.

If you have a noise ingress problem, feedline decoupling is the
answer, not a better impedance match. Also,feedline decoupling, and
impedance matching, or SWR, are totally unrelated. You can have great
decoupling with an 80 to 1 mismatch. Or you can have a perfect 1:1
match with horrible decoupling. They are totally unrelated. I'm not
lucky. I live in the city of Houston amid all kinds of noise
generating crap. But due to decent feedline decoupling, any noise I
hear is picked up from the antenna. And any attempts to achieve a
better match do not increase my s/n ratio, being as I always have
enough signal level to begin with even with no matching.

Most antennas output impedance is nowhere near the typical 50-ohm coax
and a transformation can remedy that.

But it doesn't matter. You don't have enough loss with the mismatch to
worry about with any decent radio. It's just not enough to knock you
out of the water. I did the math on this a few months ago, and posted
here to demonstrate this. This has been debated before many times. I
used coax feed with wild feedpoint impedances just to ensure a worst
case as far as feeder loss. It doesn't amount to enough to hurt you.
If it does, you have a lame radio. If you used a random wire direct
with no feeder, there is even less loss. For receiving, the mismatch
in that case doesn't matter enough to worry about at all.

Well OK I guess my radios are lame or busted. I must be imagining things
when signals go from ³I can just make it out S1² to ³easy to listen to
S3² on the folded dipole with the transformer. My other loop antennas
must not be working right either.

Is the S1 with the folded dipole fed directly without the transformer,
or another antenna? It sounds like you have or had a noise ingress
problem if the noise does not increase at the same level as the signal
when the transformer is added.
If this is the case, again, this would not be a function of impedance
matching, but a function of better feedline decoupling. The decoupling
is improving the s/n ratio, not the impedance transformation. If the
signal was S1, it should have been solid copy, if it is at S3. If it
wasn't, the overriding noise was not picked up by the antenna. It was
picked up on the outer shield of the coax down in the shack, piped up
to the feedpoint, and then piped back down to the radio on the inner
part of the outer shield. "I assume you used coax"..S1 is plenty of
signal level for solid copy if no shack noise is drowning it out.
What's the problem with the loop? Lots of noise also? MK

In article ,
(Mark Keith) wrote:

Telamon wrote in message

..
Let me explain that I live in town and have
local noise to compete with any signal I pick up. This noise must be
overcome so I only hear the program material of interest. In other words
the volume can be turned up so the program material is very loud without
any background noise or hiss. Antenna efficiency that generates more
signal energy overcomes the local noise sources. You must be unusually
lucky to live in a location where all you pick up is either broadcast
signal or atmospheric noise. I don¹t think most people are as fortunate.

I assume your noise must be shack generated, and is an ingress
problem. I would think anyway. If the noise was local, but picked up
from the antenna itself
along with the desired station, then adding the transformer would not
change the s/n ratio. The noise would increase along with the station
at an equal rate. Everything would "sound" the same. Only the S meter
would read higher.

If you have a noise ingress problem, feedline decoupling is the
answer, not a better impedance match. Also,feedline decoupling, and
impedance matching, or SWR, are totally unrelated. You can have great
decoupling with an 80 to 1 mismatch. Or you can have a perfect 1:1
match with horrible decoupling. They are totally unrelated. I'm not
lucky. I live in the city of Houston amid all kinds of noise
generating crap. But due to decent feedline decoupling, any noise I
hear is picked up from the antenna. And any attempts to achieve a
better match do not increase my s/n ratio, being as I always have
enough signal level to begin with even with no matching.

Most antennas output impedance is nowhere near the typical 50-ohm coax
and a transformation can remedy that.

But it doesn't matter. You don't have enough loss with the mismatch to
worry about with any decent radio. It's just not enough to knock you
out of the water. I did the math on this a few months ago, and posted
here to demonstrate this. This has been debated before many times. I
used coax feed with wild feedpoint impedances just to ensure a worst
case as far as feeder loss. It doesn't amount to enough to hurt you.
If it does, you have a lame radio. If you used a random wire direct
with no feeder, there is even less loss. For receiving, the mismatch
in that case doesn't matter enough to worry about at all.

Well OK I guess my radios are lame or busted. I must be imagining things
when signals go from ³I can just make it out S1² to ³easy to listen to
S3² on the folded dipole with the transformer. My other loop antennas
must not be working right either.

Is the S1 with the folded dipole fed directly without the transformer,
or another antenna? It sounds like you have or had a noise ingress
problem if the noise does not increase at the same level as the signal
when the transformer is added.
If this is the case, again, this would not be a function of impedance
matching, but a function of better feedline decoupling. The decoupling
is improving the s/n ratio, not the impedance transformation. If the
signal was S1, it should have been solid copy, if it is at S3. If it
wasn't, the overriding noise was not picked up by the antenna. It was
picked up on the outer shield of the coax down in the shack, piped up
to the feedpoint, and then piped back down to the radio on the inner
part of the outer shield. "I assume you used coax"..S1 is plenty of
signal level for solid copy if no shack noise is drowning it out.
What's the problem with the loop? Lots of noise also? MK

The antenna is a folded dipole cut for 13 meters connected to the radio
with coax.

I evaluated two stations on this band. One had locally generated noise
interference and the other did not.

I tried a repeat today with switching the matching transformer in and
out of the circuit and compared it to a large ferrite toroid in its
place. The coax made one turn through the toroid. The ferrite worked as
well as the transformer on the station with the local noise on it. No
difference found on the station in the clear. In addition the
transformer did not make a difference in the S meter reading either.

It takes me several minutes to change the transformer in or out and we
had a minor geomagnetic storm yesterday so conditions changing must have
been what I saw as a performance difference.

Today conditions are more stable and I switched the transformer and / or
toroid choke in and out several times averaging the results.

So it looks like the only benefit of the transformer was isolation it
provided on the folded dipole.

--
Telamon
Ventura, California

I used to make folded dipoles out of 300 Ohm TV Twinlead and match the
feedpoint with a TV balun driving RG-6 to the receiver. It worked
pretty well into an R-390A. Including medium wave, even.

On Sun, 13 Jul 2003 18:49:34 GMT, Telamon
wrote:


The antenna is a folded dipole cut for 13 meters connected to the radio
with coax.

I evaluated two stations on this band. One had locally generated noise
interference and the other did not.

I tried a repeat today with switching the matching transformer in and
out of the circuit and compared it to a large ferrite toroid in its
place. The coax made one turn through the toroid. The ferrite worked as
well as the transformer on the station with the local noise on it. No
difference found on the station in the clear. In addition the
transformer did not make a difference in the S meter reading either.

It takes me several minutes to change the transformer in or out and we
had a minor geomagnetic storm yesterday so conditions changing must have
been what I saw as a performance difference.

Today conditions are more stable and I switched the transformer and / or
toroid choke in and out several times averaging the results.

So it looks like the only benefit of the transformer was isolation it
provided on the folded dipole.

Doesn't loose coupling pinch bandwidth? Q through the roof?

Higher Q = lower noise but not necessarily better overall voice
perfomrance, as I recall.

On 13 Jul 2003 07:40:13 -0700, (Mark Keith) wrote:

Telamon wrote in message ..
Let me explain that I live in town and have
local noise to compete with any signal I pick up. This noise must be
overcome so I only hear the program material of interest. In other words
the volume can be turned up so the program material is very loud without
any background noise or hiss. Antenna efficiency that generates more
signal energy overcomes the local noise sources. You must be unusually
lucky to live in a location where all you pick up is either broadcast
signal or atmospheric noise. I don¹t think most people are as fortunate.

I assume your noise must be shack generated, and is an ingress
problem. I would think anyway. If the noise was local, but picked up
from the antenna itself
along with the desired station, then adding the transformer would not
change the s/n ratio. The noise would increase along with the station
at an equal rate. Everything would "sound" the same. Only the S meter
would read higher.

If you have a noise ingress problem, feedline decoupling is the
answer, not a better impedance match. Also,feedline decoupling, and
impedance matching, or SWR, are totally unrelated. You can have great
decoupling with an 80 to 1 mismatch. Or you can have a perfect 1:1
match with horrible decoupling. They are totally unrelated. I'm not
lucky. I live in the city of Houston amid all kinds of noise
generating crap. But due to decent feedline decoupling, any noise I
hear is picked up from the antenna. And any attempts to achieve a
better match do not increase my s/n ratio, being as I always have
enough signal level to begin with even with no matching.

Most antennas output impedance is nowhere near the typical 50-ohm coax
and a transformation can remedy that.

But it doesn't matter. You don't have enough loss with the mismatch to
worry about with any decent radio. It's just not enough to knock you
out of the water. I did the math on this a few months ago, and posted
here to demonstrate this. This has been debated before many times. I
used coax feed with wild feedpoint impedances just to ensure a worst
case as far as feeder loss. It doesn't amount to enough to hurt you.
If it does, you have a lame radio. If you used a random wire direct
with no feeder, there is even less loss. For receiving, the mismatch
in that case doesn't matter enough to worry about at all.

Well OK I guess my radios are lame or busted. I must be imagining things
when signals go from ³I can just make it out S1² to ³easy to listen to
S3² on the folded dipole with the transformer. My other loop antennas
must not be working right either.

Is the S1 with the folded dipole fed directly without the transformer,
or another antenna? It sounds like you have or had a noise ingress
problem if the noise does not increase at the same level as the signal
when the transformer is added.
If this is the case, again, this would not be a function of impedance
matching, but a function of better feedline decoupling. The decoupling
is improving the s/n ratio, not the impedance transformation. If the
signal was S1, it should have been solid copy, if it is at S3. If it
wasn't, the overriding noise was not picked up by the antenna. It was
picked up on the outer shield of the coax down in the shack, piped up
to the feedpoint, and then piped back down to the radio on the inner
part of the outer shield. "I assume you used coax"..S1 is plenty of
signal level for solid copy if no shack noise is drowning it out.
What's the problem with the loop? Lots of noise also? MK