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.