loop antennas and noise suppresion
 

There is the knowledge amongst most hams who work low bands that a loop
antenna has much less noise than a dipole at the same height. This is
especially true in a suburban area. The ability to hear the other
station in a qso is profoundly effected by the noise level heard in your
receiver.

I just had a very long conversation with a fellow ham who has been
experimenting with antennas for over 50 years. He has lived in the same
rural place all that time. He has no homes anywhere near his own. His
noise level in his receiver is not much reduced by using a horizontal
loop. He does like loops and his most used antenna is a 160 meter quad
loop vertically mounted with its top at 200 feet.

Anyway I was trying to understand why my loop antenna reduced my noise
level in my receiver by so many S units. After at least an hour of
conversation we got to the fact that I had built a portable loop antenna
for 2 meters as a direction finder. He pointed out how sharp the null
was when this antenna was pointed (edge on) toward the source station.
He then said to take this antenna and then turn it horizontal and see if
I could hear anything. Voila. Nothing at all was heard. I finally
understood the reason for the remarkable noise immunity of the loop
antenna. The loop simply nulls all noise and signals from its edge on
plane. So, any signals from nearby homes, power lines, and industry are
received by me at this very low angle of radiation. They are nulled out.
I receive only high angle radiation. This is also true of transmitted
signal and thus the large amount of gain it has as an NVIS antenna. This
is not magic, just physics.

My 75 meter transmitted signal in the day stops at about a 300 mile
radius. This is fine for me. It may not be fine for others. I regularly
talk to California from Michigan during the night on 75. This same
antenna works DX on 40. I do not understand why at this point. I have
received an S9 signal report from Barcelona Spain on 40. It also works
other bands, but its performance on 40 meters is better than any other
band. In any case my interest in this subject was piqued when someone
here said that it was just mythology that loop antennas had any more
noise immunity than a dipole. I knew this was not true from my own
experience but wanted to understand why. '

So in finishing up, a horizontal loop probably offers little noise
immunity when operated in the countryside where you have no nearby
sources of interference. It offers a lot of noise suppression when
operated in the city or suburban areas.

Michael

loop antennas and noise suppresion
 

On Tue, 19 Jun 2012 12:59:43 -0500, Boomer wrote:

There is the knowledge amongst most hams who work low bands that a loop
antenna has much less noise than a dipole at the same height. This is
especially true in a suburban area. The ability to hear the other
station in a qso is profoundly effected by the noise level heard in your
receiver.

I just had a very long conversation with a fellow ham who has been
experimenting with antennas for over 50 years. He has lived in the same
rural place all that time. He has no homes anywhere near his own. His
noise level in his receiver is not much reduced by using a horizontal
loop. He does like loops and his most used antenna is a 160 meter quad
loop vertically mounted with its top at 200 feet.

Anyway I was trying to understand why my loop antenna reduced my noise
level in my receiver by so many S units. After at least an hour of
conversation we got to the fact that I had built a portable loop antenna
for 2 meters as a direction finder. He pointed out how sharp the null
was when this antenna was pointed (edge on) toward the source station.
He then said to take this antenna and then turn it horizontal and see if
I could hear anything. Voila. Nothing at all was heard. I finally
understood the reason for the remarkable noise immunity of the loop
antenna. The loop simply nulls all noise and signals from its edge on
plane. So, any signals from nearby homes, power lines, and industry are
received by me at this very low angle of radiation. They are nulled out.
I receive only high angle radiation. This is also true of transmitted
signal and thus the large amount of gain it has as an NVIS antenna. This
is not magic, just physics.

My 75 meter transmitted signal in the day stops at about a 300 mile
radius. This is fine for me. It may not be fine for others. I regularly
talk to California from Michigan during the night on 75. This same
antenna works DX on 40. I do not understand why at this point. I have
received an S9 signal report from Barcelona Spain on 40. It also works
other bands, but its performance on 40 meters is better than any other
band. In any case my interest in this subject was piqued when someone
here said that it was just mythology that loop antennas had any more
noise immunity than a dipole. I knew this was not true from my own
experience but wanted to understand why. '

So in finishing up, a horizontal loop probably offers little noise
immunity when operated in the countryside where you have no nearby
sources of interference. It offers a lot of noise suppression when
operated in the city or suburban areas.

Michael

One thing must be mentioned:
The noise cancelling effect of loops is best when the loop is small
compared to the wavelength.
As the loop gets greater, the effect reduces to nil.

Imagine an electric field
------------------------------------
------------------------------------
------------------------------------
------------------------------------
------------------------------------

now imagine the loop, I can only draw a square
in fixed pitch font:

upper conductor
| |
| |
| |
| |
| |
lower conductor

It is immediately clear that the upper part
signal will be cancelled by the lower part signal
and the same applies to the left and right parts
of the loop and of course this applies also to
a circular loop in the electric field, while the signal
from a magnetic field perpendicular to the computer screen
where you are watching this, ahemm..., the magnetically
induced signal adds up around the whole circumference
of the loop.

I hope the SECRET of the loop is finally lifted
and everybody says: yeah, I knew it anyway,
you don't have to tell me, it is so simple.

Large loops do not cancel out the electric signal completely
as the el. field is not in phase on all sides of the loop
and therefore such a loop should be shielded.
When acting at 20 meters, a meter diameter loop is small
compared to the wavelength, at 150 MHz a 40cm diam. loop
is no longer small compared to the wavelength.
This is where shielding helps to minimize electrical
field pickup.

w.

loop antennas and noise suppresion
 

On Tuesday, June 19, 2012 12:59:43 PM UTC-5, Boomer wrote:
So in finishing up, a horizontal loop probably offers little noise
immunity when operated in the countryside where you have no nearby
sources of interference.

A loop antenna reduces one type of noise considerably compared to a dipole, i.e. precipitation static which is unrelated to EM far-field signals.

http://www.its.bldrdoc.gov/fs-1037/dir-028/_4096.htm

loop antennas and noise suppresion
 

On Tue, 19 Jun 2012 12:45:55 -0700 (PDT), W5DXP
wrote:

On Tuesday, June 19, 2012 12:59:43 PM UTC-5, Boomer wrote:
So in finishing up, a horizontal loop probably offers little noise
immunity when operated in the countryside where you have no nearby
sources of interference.

A loop antenna reduces one type of noise considerably compared to a dipole, i.e. precipitation static which is unrelated to EM far-field signals.

http://www.its.bldrdoc.gov/fs-1037/dir-028/_4096.htm

If you ground your dipole properly, you have no static.


w.

loop antennas and noise suppresion
 

On Tue, 19 Jun 2012 12:45:55 -0700 (PDT), W5DXP
wrote:

On Tuesday, June 19, 2012 12:59:43 PM UTC-5, Boomer wrote:
So in finishing up, a horizontal loop probably offers little noise
immunity when operated in the countryside where you have no nearby
sources of interference.

A loop antenna reduces one type of noise considerably compared to a dipole, i.e. precipitation static which is unrelated to EM far-field signals.

http://www.its.bldrdoc.gov/fs-1037/dir-028/_4096.htm

If you ground your dipole properly, you have less static.
Commercial dipole antennas also are shielded for that reason.
Ever seen one?

w.

loop antennas and noise suppresion
 

On 6/19/2012 12:59 PM, Boomer wrote:
There is the knowledge amongst most hams who work low bands that a loop
antenna has much less noise than a dipole at the same height. This is
especially true in a suburban area. The ability to hear the other
station in a qso is profoundly effected by the noise level heard in your
receiver.

I just had a very long conversation with a fellow ham who has been
experimenting with antennas for over 50 years. He has lived in the same
rural place all that time. He has no homes anywhere near his own. His
noise level in his receiver is not much reduced by using a horizontal
loop. He does like loops and his most used antenna is a 160 meter quad
loop vertically mounted with its top at 200 feet.

Anyway I was trying to understand why my loop antenna reduced my noise
level in my receiver by so many S units. After at least an hour of
conversation we got to the fact that I had built a portable loop antenna
for 2 meters as a direction finder. He pointed out how sharp the null
was when this antenna was pointed (edge on) toward the source station.
He then said to take this antenna and then turn it horizontal and see if
I could hear anything. Voila. Nothing at all was heard. I finally
understood the reason for the remarkable noise immunity of the loop
antenna. The loop simply nulls all noise and signals from its edge on
plane. So, any signals from nearby homes, power lines, and industry are
received by me at this very low angle of radiation. They are nulled out.
I receive only high angle radiation. This is also true of transmitted
signal and thus the large amount of gain it has as an NVIS antenna. This
is not magic, just physics.

My 75 meter transmitted signal in the day stops at about a 300 mile
radius. This is fine for me. It may not be fine for others. I regularly
talk to California from Michigan during the night on 75. This same
antenna works DX on 40. I do not understand why at this point. I have
received an S9 signal report from Barcelona Spain on 40. It also works
other bands, but its performance on 40 meters is better than any other
band. In any case my interest in this subject was piqued when someone
here said that it was just mythology that loop antennas had any more
noise immunity than a dipole. I knew this was not true from my own
experience but wanted to understand why. '

I was referring more to small loops used for receiving. Not large
loops.. It's mostly in the case of small loops that many claim a
shielded loop is "quieter" than an unshielded loop. I still consider
that claim as pure hogwash...

This is not the same as the full size horizontal loops you are using
on 75m. But.. Even in this case, the loop is not any "quieter" than
the dipole. Like I said before, and you've had verified by the other
guy, it's the pattern that changes, and may receive less signal at
certain heights or angles. There is no "immunity" to noise. It's just
that the change in pattern has less gain at the lower angles than the
usual dipole at the same height.
As you have noted with your conversions with the other guy...
If the noise were from overhead, as in lightning 200 miles away, the
noise of which goes up, and reflected right back down like any other
signal, the loop would be the noisiest, by about a 1/2 db.

If you model a 80m dipole at 30 feet, the gain at 5 degrees is -10.49
dbi according to the plot I'm looking at in eznec.
If you model an 80m full size horizontal loop at 30 feet, the gain at
the same 5 degrees is -12.72 dbi. So.. about 2 db or so, which happens
to be the appx gain the loop has over a dipole in free space.

So, if you have a noise source on the horizon at 5 degrees, you can
expect it to be a good 2 db down on the loop. But even 2 db is not
all that much. Usually less than an S meter on most receivers, but
could vary. So on paper, the signals at low elevations should be down
on the loop, but not hugely so.
The only difference in the pattern between the two antennas is the
dipoles pattern is a little more squat than the one from the loop.
The loop has a tighter beamwidth than the dipole.

At 90 degrees, "straight up" there is only about .4 db difference
between the two antennas. "8.82 dbi vs 8.41 dbi" That's hardly
enough difference to see on a meter. And one reason why I came to
the conclusion the loops were not worth the extra work and wire..
But I'm not trying to reduce signals from low elevations..

If you raised both antennas to 50 feet, the gain at 5 degrees
with the dipole would slightly increase.
With the horizontal loop at 50 ft, the gain at 5 degrees will be
even less than at 30 ft. I wasn't really expecting that, but
that's what the plots are showing.

Both are very good at NVIS paths. BTW, both are using the same
"medium ground" qualities in eznec.
The best way to see the difference in pattern is modeling them.
This is the elevation plot of the 80m dipole at 30 ft.
http://home.comcast.net/~nm5k/80dipole.jpg

This is the 80m horizontal loop at 30 ft.
http://home.comcast.net/~nm5k/80horloop.jpg

Both were made using the eznec demo.
http://www.eznec.com/demoinfo.htm

So in finishing up, a horizontal loop probably offers little noise
immunity when operated in the countryside where you have no nearby
sources of interference. It offers a lot of noise suppression when
operated in the city or suburban areas.

Michael

One problem is calling it noise immunity. When one says a
loop is immune to noise, it *is* a myth.
If an antenna were immune to noise, it would be immune to all
signals. Would be a fairly useless piece of hardware.
If you point a loop towards noise, it will pick it up just as well as
any other antenna, if the gain at a certain angle were equal or greater
than another antenna.
Saying it has less gain at a certain lower angle is more accurate in
your case. And that gain at low angles will increase as you raise the
antenna off the ground.

BTW, 300 miles is about average for 80 in the day, dipole or
loop.. And your loop couldn't be too awful bad at the somewhat
lower angles, or your contacts to CA wouldn't pan out too well.
That is one handy thing about the eznec program. You can use the
mouse and place the green angle indicator at any angle, and see
what the gain will be. You can see on both of those plots I
set it for 5 degrees. The "DBmax" is the level compared to the
gain at it's maximum angle, which in both of these cases, is straight
up.

I'm in the city of Houston, not out in the country. And I never
noticed the horizontal loop to receive much less local noise
than the dipoles or turnstiles I have used.
But generally, I don't have bad noise that would overpower
the usual atmospheric noise on 80m at night.

loop antennas and noise suppresion
 

On 6/20/2012 2:12 AM, NM5K wrote:

Saying it has less gain at a certain lower angle is more accurate in
your case. And that gain at low angles will increase as you raise the
antenna off the ground.


Ooops.. That is generally the case, but as earlier mentioned, I
actually saw less gain at 5 degrees with the hor loop at 50 ft,
than I did with it at 30 ft.. Which would likely help with
reducing your local noise. I don't know how high yours is..
But the dipole gain at low angles did increase with height
above ground.

loop antennas and noise suppresion
 

On Tuesday, June 19, 2012 2:59:12 PM UTC-5, Helmut Wabnig wrote:
If you ground your dipole properly, you have less static.

Yes, there are a number of approaches: transorb, resistor, choke, 4:1 voltage balun, convert to a folded-dipole, arrestors, etc. But most hams don't ground their dipoles properly.
--
73, Cecil, w5dxp.com

loop antennas and noise suppresion
 

On Wednesday, June 20, 2012 6:49:25 AM UTC-5, W5DXP wrote:
On Tuesday, June 19, 2012 2:59:12 PM UTC-5, Helmut Wabnig wrote:
If you ground your dipole properly, you have less static.

Yes, there are a number of approaches: transorb, resistor, choke, 4:1 voltage balun, convert to a folded-dipole, arrestors, etc. But most hams don't ground their dipoles properly.
--
73, Cecil, w5dxp.com

loop antennas and noise suppresion
 

On Wednesday, June 20, 2012 2:12:09 AM UTC-5, NM5K wrote:
If an antenna were immune to noise, it would be immune to all
signals.

Don't forget the effects of polarization. At my previous QTH, my horizontal dipole was about 2 S-units less noisy than my vertical even when communicating with remote vertical antennas.
--
73, Cecil, w5dxp.com

loop antennas and noise suppresion
 

On Tue, 19 Jun 2012 12:59:43 -0500, Boomer wrote:
(snip)
After at least an hour of
conversation we got to the fact that I had built a portable loop antenna
for 2 meters as a direction finder. He pointed out how sharp the null
was when this antenna was pointed (edge on) toward the source station.
He then said to take this antenna and then turn it horizontal and see if
I could hear anything. Voila. Nothing at all was heard.
(snip)
ISTR with my portable shielded loop, when its horizontal, its omni;
when its vertical, max received signal is when the edge is pointing to
the tx. The null happens when the plane of the loop is at right angles to
a line to the tx.

loop antennas and noise suppresion
 

On 6/20/2012 7:24 AM, W5DXP wrote:
On Wednesday, June 20, 2012 2:12:09 AM UTC-5, NM5K wrote:
If an antenna were immune to noise, it would be immune to all
signals.

Don't forget the effects of polarization. At my previous QTH, my horizontal dipole was about 2 S-units less noisy than my vertical even when communicating with remote vertical antennas.
--
73, Cecil, w5dxp.com


I'm not. I'm just trying to show that an antenna can't tell what
is noise, and what is an actual desired signal. To the antenna,
they are both the same. RF.. One can not magically filter noise,
without filtering the actual signals along with it.
This applies more to the small receiving loop, comparing shielded
to non shielded, but also would apply in most any other case.
I'm fairly comfortable saying the claims of reduced noise pickup
with shielded loops is a myth. I've compared them, and I saw no
difference here. And that includes the usual far field signals,
but also closer local noise, such as monitor noise from the shack,
etc..
I never saw any difference with that type of local noise either.
Both types picked it up equally well if it was there.
And both types could null it out equally well, if from a single
source.

loop antennas and noise suppresion
 

NM5K wrote:
I'm not. I'm just trying to show that an antenna can't tell what
is noise, and what is an actual desired signal. To the antenna,
they are both the same. RF.. One can not magically filter noise,
without filtering the actual signals along with it.
This applies more to the small receiving loop, comparing shielded
to non shielded, but also would apply in most any other case.

Say, you have interference with a local origin and a signal with
a remote origin, wouldn't it be possible to tell the two apart?

E.g. by using two antennas. The received signal is the same on
both antennas but the noise is different. This can be used to
cancel out the local noise but keep the remote signal. Phasing boxes
that operate on this principle are commercially available, so maybe
it is possible.

loop antennas and noise suppresion
 

On 6/20/2012 11:14 AM, Rob wrote:
NM5K wrote:
I'm not. I'm just trying to show that an antenna can't tell what
is noise, and what is an actual desired signal. To the antenna,
they are both the same. RF.. One can not magically filter noise,
without filtering the actual signals along with it.
This applies more to the small receiving loop, comparing shielded
to non shielded, but also would apply in most any other case.

Say, you have interference with a local origin and a signal with
a remote origin, wouldn't it be possible to tell the two apart?

E.g. by using two antennas. The received signal is the same on
both antennas but the noise is different. This can be used to
cancel out the local noise but keep the remote signal. Phasing boxes
that operate on this principle are commercially available, so maybe
it is possible.


Sure, but that's a whole different thing entirely.
That's nothing to do with the antennas themselves.

loop antennas and noise suppresion
 

NM5K wrote:
On 6/20/2012 11:14 AM, Rob wrote:
NM5K wrote:
I'm not. I'm just trying to show that an antenna can't tell what
is noise, and what is an actual desired signal. To the antenna,
they are both the same. RF.. One can not magically filter noise,
without filtering the actual signals along with it.
This applies more to the small receiving loop, comparing shielded
to non shielded, but also would apply in most any other case.

Say, you have interference with a local origin and a signal with
a remote origin, wouldn't it be possible to tell the two apart?

E.g. by using two antennas. The received signal is the same on
both antennas but the noise is different. This can be used to
cancel out the local noise but keep the remote signal. Phasing boxes
that operate on this principle are commercially available, so maybe
it is possible.


Sure, but that's a whole different thing entirely.
That's nothing to do with the antennas themselves.

But once you move a bit further away and consider the two antennas
and phasingbox together as a single antenna, it suddenly is capable
of telling apart local noise and distant signal. That is promising.

loop antennas and noise suppresion
 

On 6/19/2012 12:59 PM, Boomer wrote:
There is the knowledge amongst most hams who work low bands that a loop
antenna has much less noise than a dipole at the same height. This is
especially true in a suburban area. The ability to hear the other
station in a qso is profoundly effected by the noise level heard in your
receiver.

I just had a very long conversation with a fellow ham who has been
experimenting with antennas for over 50 years. He has lived in the same
rural place all that time. He has no homes anywhere near his own. His
noise level in his receiver is not much reduced by using a horizontal
loop. He does like loops and his most used antenna is a 160 meter quad
loop vertically mounted with its top at 200 feet.

Anyway I was trying to understand why my loop antenna reduced my noise
level in my receiver by so many S units. After at least an hour of
conversation we got to the fact that I had built a portable loop antenna
for 2 meters as a direction finder. He pointed out how sharp the null
was when this antenna was pointed (edge on) toward the source station.
He then said to take this antenna and then turn it horizontal and see if
I could hear anything. Voila. Nothing at all was heard. I finally
understood the reason for the remarkable noise immunity of the loop
antenna. The loop simply nulls all noise and signals from its edge on
plane. So, any signals from nearby homes, power lines, and industry are
received by me at this very low angle of radiation. They are nulled out.
I receive only high angle radiation. This is also true of transmitted
signal and thus the large amount of gain it has as an NVIS antenna. This
is not magic, just physics.

My 75 meter transmitted signal in the day stops at about a 300 mile
radius. This is fine for me. It may not be fine for others. I regularly
talk to California from Michigan during the night on 75. This same
antenna works DX on 40. I do not understand why at this point. I have
received an S9 signal report from Barcelona Spain on 40. It also works
other bands, but its performance on 40 meters is better than any other
band. In any case my interest in this subject was piqued when someone
here said that it was just mythology that loop antennas had any more
noise immunity than a dipole. I knew this was not true from my own
experience but wanted to understand why. '

So in finishing up, a horizontal loop probably offers little noise
immunity when operated in the countryside where you have no nearby
sources of interference. It offers a lot of noise suppression when
operated in the city or suburban areas.

Michael


As I said above, I am not talking about atmospheric noise. I am
suppressing the local noise generated in my community by various
electrical and electronic devices. These are close enough to arrive
where I live from an extremely low angle. This low angle is exactly what
my loop "magically" nulls out.

I understand now that when I use it at multiple wavelengths that it no
longer behaves as it does where it is a single wavelength on 75 meters.

All the contrarians keep citing atmospheric noise cannot be suppressed
with a loop. Please read my post above more carefully. I do not make
that claim. If you read carefully you will see that I am trying to
suppress ".... So, any signals from nearby homes, power lines, and
industry are received by me at this very low angle of radiation....."

Now if you are claiming this does not work, then say so rather than
talking about atmospheric noise.

Those of us who live in a suburban area bombarded with local noise know
very well which antenna will be more quiet. At least those who have
tried a loop. I suppose there are some suburban areas without noise. I
have not lived in one.

I always prefer empirical evidence over theoretical postulates. Those
who prefer to defer to a theory over evidence are welcome to do so. I
like to use what actually works.

There appears to be an anti-loop antenna feeling among some people. I
have no such innate prejudice against most antennas. I have tried
various types of antennas and use what works best where I live. I found
the random wire antenna and the G5RV to be the worst performing of all
antennas I have tried. If I had no room for a loop, I would use a folded
dipole. After that, I would use a simple 1/2 wave dipole. I have tried
the double bazooka but found it only marginally wider in bandwidth than
a dipole and heavier and more difficult to support.

I do admit that I find the wide spread acceptance of the G5RV by new
hams to be a mistake. I certainly understand why they might originally
chose this antenna. It claims operation from 75 meters to 10 with just a
102 foot length. This is an attractive specification, but comes with a
serious performance cost.

Michael

loop antennas and noise suppresion
 

On 6/20/2012 12:05 PM, Boomer wrote:

As I said above, I am not talking about atmospheric noise. I am
suppressing the local noise generated in my community by various
electrical and electronic devices. These are close enough to arrive
where I live from an extremely low angle. This low angle is exactly what
my loop "magically" nulls out.

I see little if any chatter about atmospheric noise.
The only mention I've made of it was to say if the noise is
from overhead, the horizontal loop will receive it very well.
As will a dipole, turnstile, and many other antennas.


I understand now that when I use it at multiple wavelengths that it no
longer behaves as it does where it is a single wavelength on 75 meters.

Also the height above ground in wavelength should be considered.

All the contrarians keep citing atmospheric noise cannot be suppressed
with a loop. Please read my post above more carefully. I do not make
that claim. If you read carefully you will see that I am trying to
suppress ".... So, any signals from nearby homes, power lines, and
industry are received by me at this very low angle of radiation....."

Now if you are claiming this does not work, then say so rather than
talking about atmospheric noise.

I've already stated two or three times that it's the pattern
that causes what you see. I never said it didn't work.
In fact, I showed in the model that 2 db would be fairly easy to
come by. Maybe more, if you raised the loop to 50 ft.
All you are doing is continuing to show I was correct as far as my
initial guess for the reason. I said it was almost surely the pattern
from the first post. You seem to be intent on proving me right.. :/
OK, I give up. You win. I concede I was right from the first guess.. :|

I know what you are doing works for the noise you are trying to reduce.
But it's working for a different reason that some *others* propose,
usually when discussing small loops.
Like I say, the noise issue I harp on is more often discussed when
talking about small receiving loops, not full size loops.
It's a bit different issue than what you see with a full size
horizontal loop on 75m.



Those of us who live in a suburban area bombarded with local noise know
very well which antenna will be more quiet. At least those who have
tried a loop. I suppose there are some suburban areas without noise. I
have not lived in one.

There are no absolutes.. It depends on the noise source, polarity,
direction, etc.
If I have noise, it's usually line noise from the power lines.
There could be cases where the dipole received less of that noise
if the orientation was just right.


I always prefer empirical evidence over theoretical postulates. Those
who prefer to defer to a theory over evidence are welcome to do so. I
like to use what actually works.

As do I. And I've tried the loops, believe me.. When it comes to 75m,
I've pretty much tried everything trying to get the very last drop of
performance to NVIS paths. 160, 80 and 40 is where I've always spent
most of my time.


There appears to be an anti-loop antenna feeling among some people. I
have no such innate prejudice against most antennas. I have tried
various types of antennas and use what works best where I live. I found
the random wire antenna and the G5RV to be the worst performing of all
antennas I have tried. If I had no room for a loop, I would use a folded
dipole. After that, I would use a simple 1/2 wave dipole. I have tried
the double bazooka but found it only marginally wider in bandwidth than
a dipole and heavier and more difficult to support.

I have no problems with a loop. I just have a problem with saying they
receive less noise for the wrong reasons.
Note the title of this thread. It's mainly about small receiving loops,
and the title infers that they may offer noise suppression if you use a
shielded loop vs an unshielded loop.
I consider that hogwash. All the shielded version offers is a better
chance of it being balanced. But it's quite easy to build an unshielded
loop that is balanced. If both are balanced, both will perform the same
assuming the same size loop.

The double bazooka actually has more loss than a plain wire dipole.
It's the loss that increases the bandwidth.


I do admit that I find the wide spread acceptance of the G5RV by new
hams to be a mistake. I certainly understand why they might originally
chose this antenna. It claims operation from 75 meters to 10 with just a
102 foot length. This is an attractive specification, but comes with a
serious performance cost.

The G5RV can be OK if fed properly. Straight ladder line would
work much better than the usual coax/choke/ladder line that many
use. It's the silly feed systems they use that kill the performance.
It's that coax/choke/ladder line feed config that kills the performance
of most of the commercial windoms also.
If I ran a G5RV, or any other single dipole for multi band use,
I'd feed with ladder line the whole way from the rig to the antenna.

loop antennas and noise suppresion
 

"W5DXP" wrote in message
...
On Tuesday, June 19, 2012 2:59:12 PM UTC-5, Helmut Wabnig wrote:
If you ground your dipole properly, you have less static.

Yes, there are a number of approaches: transorb, resistor, choke, 4:1
voltage balun, convert to a folded-dipole, arrestors, etc. But most hams
don't ground their dipoles properly.
--
73, Cecil, w5dxp.com

I have no idea how to ground a dipole and I don't think I've ever done it
except by accident.

I welcome any direction. (Having just read the foregoing, I have not
searched the Internet, yet.)

"Sal
(KD6VKW)

loop antennas and noise suppresion
 

In message , Boomer
writes




I do admit that I find the wide spread acceptance of the G5RV by new
hams to be a mistake. I certainly understand why they might originally
chose this antenna. It claims operation from 75 meters to 10 with just
a 102 foot length. This is an attractive specification, but comes with
a serious performance cost.

The G5RV is not a miracle antenna. However, those who find that it does
not perform fairly well probably have not bothered to find out why it is
like it is, and where the radiation goes on the various amateur bands.
If they don't want an antenna with a radiation pattern like the G5RV,
then they should choose a different type of antenna.
--
Ian

loop antennas and noise suppresion
 

On Wednesday, June 20, 2012 3:40:40 PM UTC-5, Sal M. O'Nella wrote:
I have no idea how to ground a dipole and I don't think I've ever done it
except by accident.

Apparently, you have never had P-static problems with your dipoles. I, however, had a coax connector start arcing in the middle of the night and it sounded like a machine gun.
--
73, Cecil, w5dxp.com

loop antennas and noise suppresion
 

On Wednesday, June 20, 2012 12:05:07 PM UTC-5, Boomer wrote:
This is an attractive specification, but comes with a
serious performance cost.

A G5RV is a good performer on 75m, 40m, 20m, and 12m. Here's why on 75m and 40m.

http://www.w5dxp.com/G5RV.HTM
--
73, Cecil, w5dxp.com

loop antennas and noise suppresion
 

"W5DXP" wrote in message
...
On Wednesday, June 20, 2012 3:40:40 PM UTC-5, Sal M. O'Nella wrote:
I have no idea how to ground a dipole and I don't think I've ever done it
except by accident.

Apparently, you have never had P-static problems with your dipoles. I,
however, had a coax connector start arcing in the middle of the night and
it sounded like a machine gun.
--
73, Cecil, w5dxp.com

Nonsuch, Cecil, unless it's been an off-again-on-again
problem that I simply never appreciated for its affect on
my QSOs.

With Field Day coming and my being the Field Day Chairman
for the local club (www.sobars.org), as well as our President,
any diddling with my home QTH dipoles must wait.

I am taking an unproven design for a 20m Cubical quad to FD.
By EZNEC, it looks good but it wants a 75-ohm feed, which I am
prepared to provide. I have a choked cable ready to go.

In your opinion, is there a ground required? At the antenna or at
my van? Both? I own some ground rods and a sledgehammer.

(Last year, I used a 20m dipole at 30 feet, operating out of my van.
Everything floated above ground without incident and many QSOs.)

I value your opiniion.

73
"Sal"
(really KD6VKW)

loop antennas and noise suppresion
 

"Sal M. O'Nella" napisa³ w wiadomo¶ci
...


(Last year, I used a 20m dipole at 30 feet, operating out of my van.
Everything floated above ground without incident and many QSOs.)

I value your opiniion.

In Marconi opinion:
http://www.nobelprize.org/nobel_priz...ni-lecture.pdf

"By "connected to earth" I do not necessarily mean an ordinary metallic
connection as used for ordinary wire telegraphs.
The earth wire may have a condenser in series with it, or it may be
connected to what is really equivalent, a capacity area placed close to the
surface
of the ground (Fig. 4).
It is now perfectly well known that a condenser, if large enough, does not
prevent the passage of high frequency oscillations, and therefore in these
cases
the earth is for all practical purposes connected to the antennae."


And Wiki:
"The use of the term ground (or earth) is so common in electrical and
electronics applications that circuits in portable electronic devices such
as cell phones and media players as well as circuits in vehicles such as
ships, aircraft, and spacecraft may be spoken of as having a "ground"
connection without any actual connection to the Earth. This is usually a
large conductor attached to one side of the power supply (such as the
"ground plane" on a printed circuit board) which serves as the common return
path for current from many different components in the circuit." From:
http://en.wikipedia.org/wiki/Ground_(electricity)
S*

loop antennas and noise suppresion
 

Szczepan Bialek wrote:

"Sal M. O'Nella" napisa? w wiadomo?ci
...


(Last year, I used a 20m dipole at 30 feet, operating out of my van.
Everything floated above ground without incident and many QSOs.)

I value your opiniion.

In Marconi opinion:

Marconi was wrong, idiot.

And the topic of discussion is prevention of static build up on antennas
which requires a particular set of circumstances to occur and does NOT
happen all the time and everywhere.

You are an idiot.

loop antennas and noise suppresion
 

"Szczepan Bialek" wrote in message
...

"Sal M. O'Nella" napisa³ w wiadomo¶ci
...


(Last year, I used a 20m dipole at 30 feet, operating out of my van.
Everything floated above ground without incident and many QSOs.)

I value your opiniion.

In Marconi opinion:
http://www.nobelprize.org/nobel_priz...ni-lecture.pdf

"By "connected to earth" I do not necessarily mean an ordinary metallic
connection as used for ordinary wire telegraphs.
The earth wire may have a condenser in series with it, or it may be
connected to what is really equivalent, a capacity area placed close to
the
surface
of the ground (Fig. 4).
It is now perfectly well known that a condenser, if large enough, does not
prevent the passage of high frequency oscillations, and therefore in these
cases
the earth is for all practical purposes connected to the antennae."


And Wiki:
"The use of the term ground (or earth) is so common in electrical and
electronics applications that circuits in portable electronic devices such
as cell phones and media players as well as circuits in vehicles such as
ships, aircraft, and spacecraft may be spoken of as having a "ground"
connection without any actual connection to the Earth. This is usually a
large conductor attached to one side of the power supply (such as the
"ground plane" on a printed circuit board) which serves as the common
return
path for current from many different components in the circuit." From:
http://en.wikipedia.org/wiki/Ground_(electricity)
S*

What is your point is (other than demonstrating copy-and-paste)? If it is
that "all aerials require an earth" then you're clearly ignoring previous
postings which have said that this is not the case.
The Wiki item doesn't seem to appreciate the difference between a return
path on a circuit board and a connection to earth.

Regards, Ian.

loop antennas and noise suppresion
 

On 6/22/2012 10:20 AM, Szczepan Bialek wrote:
"Sal M. napisa³ w wiadomo¶ci
...


(Last year, I used a 20m dipole at 30 feet, operating out of my van.
Everything floated above ground without incident and many QSOs.)

I value your opiniion.

In Marconi opinion:
http://www.nobelprize.org/nobel_priz...ni-lecture.pdf

"By "connected to earth" I do not necessarily mean an ordinary metallic
connection as used for ordinary wire telegraphs.
The earth wire may have a condenser in series with it, or it may be
connected to what is really equivalent, a capacity area placed close to the
surface
of the ground (Fig. 4).
It is now perfectly well known that a condenser, if large enough, does not
prevent the passage of high frequency oscillations, and therefore in these
cases
the earth is for all practical purposes connected to the antennae."


And Wiki:
"The use of the term ground (or earth) is so common in electrical and
electronics applications that circuits in portable electronic devices such
as cell phones and media players as well as circuits in vehicles such as
ships, aircraft, and spacecraft may be spoken of as having a "ground"
connection without any actual connection to the Earth. This is usually a
large conductor attached to one side of the power supply (such as the
"ground plane" on a printed circuit board) which serves as the common return
path for current from many different components in the circuit." From:
http://en.wikipedia.org/wiki/Ground_(electricity)
S*


And he changes his argument again. Because now the electrons cannot
flow to ground. Which blows his whole "antennas radiate electrons"
argument.

Troll or moron? You decide.

tom
K0TAR

loop antennas and noise suppresion
 

"tom" napisal w wiadomosci
. net...
On 6/22/2012 10:20 AM, Szczepan Bialek wrote:
"Sal M. napisa³ w wiadomo¶ci
...


(Last year, I used a 20m dipole at 30 feet, operating out of my van.
Everything floated above ground without incident and many QSOs.)

I value your opiniion.

In Marconi opinion:
http://www.nobelprize.org/nobel_priz...ni-lecture.pdf

"By "connected to earth" I do not necessarily mean an ordinary metallic
connection as used for ordinary wire telegraphs.
The earth wire may have a condenser in series with it, or it may be
connected to what is really equivalent, a capacity area placed close to
the
surface
of the ground (Fig. 4).
It is now perfectly well known that a condenser, if large enough, does
not
prevent the passage of high frequency oscillations, and therefore in
these
cases
the earth is for all practical purposes connected to the antennae."


And Wiki:
"The use of the term ground (or earth) is so common in electrical and
electronics applications that circuits in portable electronic devices
such
as cell phones and media players as well as circuits in vehicles such as
ships, aircraft, and spacecraft may be spoken of as having a "ground"
connection without any actual connection to the Earth. This is usually a
large conductor attached to one side of the power supply (such as the
"ground plane" on a printed circuit board) which serves as the common
return
path for current from many different components in the circuit." From:
http://en.wikipedia.org/wiki/Ground_(electricity)
S*


And he changes his argument again. Because now the electrons cannot flow
to ground. Which blows his whole "antennas radiate electrons" argument.

All time the electrons flow to or from the ground.
"Let me answer some of your questions. Capacitors loose their charge both
through the insulation between the plates and through the air surrounding
the capacitor. The charge is a surplus of electrons on one plate and a
rarefaction of electrons on the other. Where the electrons are compacted
(the negative plate) the electrons tend to push each other off. Where there
is a deficit of electrons (the positive plate) electrons are attracted from
other sources - air, the positive plate. Both of these actions tend to
decrease the potential difference between the plates... to discharge the
capacitor. From: http://www.newton.dep.anl.gov/askasc...0/phy00900.htm


Troll or moron? You decide.

" Variable capacitors with their plates open to the atmosphere were commonly
used in radio tuning circuits."
If you have such try to measure "the Capacitor charge holding" and decide.
S*

loop antennas and noise suppresion
 

"Szczepan Bialek" wrote in message
.. .

All time the electrons flow to or from the ground.
"Let me answer some of your questions. Capacitors loose their charge both
through the insulation between the plates and through the air surrounding
the capacitor. The charge is a surplus of electrons on one plate and a
rarefaction of electrons on the other. Where the electrons are compacted
(the negative plate) the electrons tend to push each other off. Where
there is a deficit of electrons (the positive plate) electrons are
attracted from other sources - air, the positive plate. Both of these
actions tend to decrease the potential difference between the plates... to
discharge the capacitor. From:
http://www.newton.dep.anl.gov/askasc...0/phy00900.htm

S*

Let's disregard the spelling error ("loose" and "lose").
The article continues thus:

"How can this be discouraged? There are a number of possibilities, but they
are selectively employed due to practical and economic reasons. Two possible
methods - Increase the distance between the plates or change the material
separating the plates. For instance glass insulators are sometimes used on
very large (tall as a house) capacitors or the capacitor may be packed in
oil. "

Anyone seen a capacitor that is as big as a house?

snip

"Often one wants a capacitor to have the largest possible capacitance. This
is accomplished by making the plates large in area and close together and
filling the space between the plates with an insulator which has a large
dielectric constant. A parallel plate capacitor has a capacitance given by C
= eA/d, where e is the dielectric constant, A is the area of the plates and
d is the separation between the plates. Notice that making the area large
and the separation small makes it easier for a current to flow between the
plates, thereby discharging them. For many purposes the small leakage
current is not a serious problem. Often a large value of capacitance is much
more important than a slow discharge. Notice that even with air between the
plates, cosmic rays will occasionally pass through the capacitor, ionizing
the air and thereby discharging the capacitor slightly."

Note the statement "makes it easier for a current to flow between the
plates". That's "between the plates" and not "flow to earth".

snip

"It is true, most capacitors tend to self-discharge about 50% in something
like 15 minutes."
That's "self-discharge" and not "discharge to earth".

For a detailed discussion of electrons, why not try posting on one
of the Physics or Science newsgroups?

Regards, Ian.

loop antennas and noise suppresion
 

"Szczepan Bialek" wrote in message
.. .
Troll or moron? You decide.

" Variable capacitors with their plates open to the atmosphere were
commonly used in radio tuning circuits."
If you have such try to measure "the Capacitor charge holding" and decide.
S*

Hi folks.

Apologies for my long posting a few minutes ago. I do not like selective
quotes but I forgot that Szczepan only understands copy-and-paste.
Of course, we all kn ow that copy-and-paste is merely the movement of
electrons flying in tight formation.

Please excuse my tryping terrors - they are merely the random movement of
heavy electrons hitting the keys on my keyboard. It's worst for me when one
falls off the keyboard and lands on my foot.

73, Ian.

loop antennas and noise suppresion
 

Szczepan Bialek wrote:

All time the electrons flow to or from the ground.

Nope.

"Let me answer some of your questions. Capacitors loose their charge both
through the insulation between the plates and through the air surrounding
the capacitor. The charge is a surplus of electrons on one plate and a
rarefaction of electrons on the other. Where the electrons are compacted
(the negative plate) the electrons tend to push each other off. Where there
is a deficit of electrons (the positive plate) electrons are attracted from
other sources - air, the positive plate. Both of these actions tend to
decrease the potential difference between the plates... to discharge the
capacitor. From: http://www.newton.dep.anl.gov/askasc...0/phy00900.htm

A valid statement but you have no clue what it is talking about or what
any of it means in the real world.

It has nothing to do with what is being discussed.

" Variable capacitors with their plates open to the atmosphere were commonly
used in radio tuning circuits."

Again, a valid statement but you have no clue what it is talking about or what
any of it means in the real world.

It has nothing to do with what is being discussed.

If you have such try to measure "the Capacitor charge holding" and decide.

This is just babble.

You are an idiot.

loop antennas and noise suppresion
 

"Ian" napisa³ w wiadomo¶ci
...
"Szczepan Bialek" wrote in message
.. .

All time the electrons flow to or from the ground.

Note the statement "makes it easier for a current to flow between the
plates". That's "between the plates" and not "flow to earth".

The Earth surface works as the plate.

snip

"It is true, most capacitors tend to self-discharge about 50% in something
like 15 minutes."
That's "self-discharge" and not "discharge to earth".

The Earth surface works as the plate.

For a detailed discussion of electrons, why not try posting on one
of the Physics or Science newsgroups?

They know what the electrons are.
S*

loop antennas and noise suppresion
 

"Szczepan Bialek" wrote in message
...

All time the electrons flow to or from the ground.

Note the statement "makes it easier for a current to flow between the
plates". That's "between the plates" and not "flow to earth".

The Earth surface works as the plate.

snip

"It is true, most capacitors tend to self-discharge about 50% in
something
like 15 minutes."
That's "self-discharge" and not "discharge to earth".

The Earth surface works as the plate.

For a detailed discussion of electrons, why not try posting on one
of the Physics or Science newsgroups?

They know what the electrons are.
S*

Hello Szczepan.

No, the earth doesn't act as a surface of a capacitor. Capacitors will
self-discharge even when they aren't connected to any circuit.

loop antennas and noise suppresion
 

Szczepan Bialek wrote:

"Ian" napisa? w wiadomo?ci
...
"Szczepan Bialek" wrote in message
.. .

All time the electrons flow to or from the ground.

Note the statement "makes it easier for a current to flow between the
plates". That's "between the plates" and not "flow to earth".

The Earth surface works as the plate.

No; you are an idiot.


snip

"It is true, most capacitors tend to self-discharge about 50% in something
like 15 minutes."
That's "self-discharge" and not "discharge to earth".

The Earth surface works as the plate.

No; you are an idiot.


For a detailed discussion of electrons, why not try posting on one
of the Physics or Science newsgroups?

They know what the electrons are.

Which means they would laugh at your idiotic babble too.

loop antennas and noise suppresion
 

"Ian" napisa³ w wiadomo¶ci
...
"Szczepan Bialek" wrote in message
...

All time the electrons flow to or from the ground.


Hello Szczepan.

No, the earth doesn't act as a surface of a capacitor. Capacitors will
self-discharge even when they aren't connected to any circuit.

My answer was to Sal. He wrote: "(Last year, I used a 20m dipole at 30
feet, operating out of my van.
Everything floated above ground without incident and many QSOs.)"

The floor of the van is the plate and the surface of the Earth is the second
plate.
S*

loop antennas and noise suppresion
 

"Szczepan Bialek" wrote in message
...

No, the earth doesn't act as a surface of a capacitor. Capacitors will
self-discharge even when they aren't connected to any circuit.

My answer was to Sal. He wrote: "(Last year, I used a 20m dipole at 30
feet, operating out of my van.
Everything floated above ground without incident and many QSOs.)"

The floor of the van is the plate and the surface of the Earth is the
second plate.
S*

Thanks, Szczepan . That made me smile. I'm sure you will find sites on the
web that will help you to understand capacitors.

Have a nice day. Ian.

loop antennas and noise suppresion
 

On Monday, June 25, 2012 2:23:22 AM UTC-5, Szczepan Bialek wrote:
The floor of the van is the plate and the surface of the Earth is the second
plate.

How about the capacitors and antennas on Voyager I and II which are still operating at the edge of the solar system?
--
73, Cecil, w5dxp.com

loop antennas and noise suppresion
 

"W5DXP" wrote in message
...
On Monday, June 25, 2012 2:23:22 AM UTC-5, Szczepan Bialek wrote:
The floor of the van is the plate and the surface of the Earth is the
second
plate.

How about the capacitors and antennas on Voyager I and II which are still
operating at the edge of the solar system?
--
73, Cecil, w5dxp.com

Hello Cecil. Do you suppose that we can regard Uranus or Pluto as a
replacement Earth?
Pity they didn't want a volunteer to be the crew of a Voyager. We could have
suggested someone ...

73, Ian.

Play nice - you do not want to end up like ME!
Friendless and alone.

IN THEORY - Marconi was correct.

IF wind blows directly across a loop antenna, it stands to reason that the wind would create a static, and when connected to a transceiver it would look for a ground to travel to - like lightning in a storm cloud - and even saying static discharge is incorrect.

Antenna's by nature is electrically charged - this is why they receive.

I could cite some irrevelant information that no one would listen to, but no one would know what I was talking about / or care.

I can tell you of one man who lives across the street from a low power AM commercial radio station -= daylighter station with about 4K transmit / that gets shocked everytime he touches his loop antenna.

It stands to reason that if it was electrostatically charged, just like shuffling your feet across the carpet floor and then touching a old water tap with copper pipe - that an arc would jump and a spark would be produced and you would get jolted.

Some good sloper antenna's also uses a discharge mech to dampen the static on the line.

A club I belong to - but did not participate with - in field days this year, built a matching network for their 240' repeater tower and loaded up the entire tower and tried to make contacts on 160 meters one year.

Someone acted ignorant and told them to get off of 160 meters - that it was for bullchitting and not for contesting =- when the club broke into their QSO - and they disconnected the matching network and threw it away.

A bunch of CB'rs in my opinion.

ONe other thing to note - and I am suprised that no one produces it, is a loop antenna for 11 meters.
If the manufacturers would get together and make a 11 meter loop and sell it to the trailer manufactuers - tuned, and would install it on the enclosed truck trailers - these 11 meter / CB radio nets would dissappear almost overnight.

Someone told them that they needed a half wavelength of coax to have a balanced feed line - no one told them that it had to be electrically a half wavelength.
Hence every other post includes how they bought 18' of coax, reguardless of make or model and how they have high swr's because their antenna will not tune up = 3 or 4 foot long - double sticks - with no ground plane and a fiberglass body.

If I had a nickle for every time I told them they would be better off with a walkie talkie - they get mad and throw me off their forums.

You could probably hold a 4' long whip antenna in your hand and do more good then mounting it on the side of a fiberglass door with no ground plane!

As far as me building a loop and worrying about static discharge or noise - a NVIS antenna is only a couple of feet off the ground and it works - it does not talk very far, maybe 1500 miles max, but it listens and is real quiet - because it does not receive as much.

Good for doing close up local work, not good for skip.

I even heard tell of a guy who buried his antenna 1 foot below ground and made some contacts, but couldn't stand the electrical burns he got every time he touched something metallic while holding or talking into the mic.

RF needs some place to go and the best path it found was out of the mic.

Marconi was a theif and a cheat, because his first across Atlantic contact never happened, he just needed something to be of proof so he could get a license to do what he wanted to do and he needed government approval to do it before he invested his own money into it.

Even Heimlic Hertz knew more about radio then Marconi did and he dismissed it as a novelty.

KHZ

MHZ

or

KILLO CYCLES

MEGGA CYCLES

YOU BE THE JUDGE!

loop antennas and noise suppresion
 

"Szczepan Bialek" wrote in message
...


"Ian" napisa³ w wiadomo¶ci
...
"Szczepan Bialek" wrote in message
...

All time the electrons flow to or from the ground.


Hello Szczepan.

No, the earth doesn't act as a surface of a capacitor. Capacitors will
self-discharge even when they aren't connected to any circuit.

# My answer was to Sal. He wrote: "(Last year, I used a 20m dipole at 30
# feet, operating out of my van.
# Everything floated above ground without incident and many QSOs.)"

# The floor of the van is the plate and the surface of the Earth is the
second
# plate.
# S*

Just as a mental exercise, assume that the entire setup...van and antenna,
is transported to a place in space where there is negligible capacitance to
the earth.

Is it your contention that the setup would operate any differently?

loop antennas and noise suppresion
 

"Szczepan Bialek" wrote in message
...

Hello Szczepan.

No, the earth doesn't act as a surface of a capacitor. Capacitors will
self-discharge even when they aren't connected to any circuit.

My answer was to Sal. He wrote: "(Last year, I used a 20m dipole at 30
feet, operating out of my van.
Everything floated above ground without incident and many QSOs.)"

The floor of the van is the plate and the surface of the Earth is the
second plate.
S*
Hello Szczepan.
Please try to take note of earlier postings. A dipole is a balanced aerial
and works without reference to earth.
Regards, Ian.