Fw: Topband: Noise and reception

[k3ky@erols.com]

Wow! Thanks a million, George. This is an example of what makes
the Topband group such a joy. I will add those comments to my
webpage writeup of the K6STI loop.
Those who read the articles will end up building an actual open wire
450 ohm line. Here, I used some of the old TV ladder line with the
plastic rod spacers about every foot. Yes, you can use the so-called
ladder line with the brown plastic that looks like oversized 300 ohm
ribbon with a lot of rectangular holes punched out-  but *only* if you
can confirm that the characteristic impedance is actually 450 ohms
or higher. Apparently a lot of the stuff runs more like 370 ohms or
so. K6STI said that stuff will not work. Further, you will get pretty
bad detuning of the antenna when it gets rain, snow, or ice on it,
and you will hear a drop in output signal level. Using real open wire
construction minimizes that.
I found K3RR and K4CIA's suggestions intriguing. Who is going to
be the first kid on the block to run directionally-switchable
horizontal receiving loops? Perhaps a 4-square of 25 footers
might be no more than 75 feet on a side. I wonder if they would
be as tricky to balance up as are 4-squares verticals? Or perhaps
even worse?
I have always wondered why the antenna modeling shows the
K6STI loop to have usably low angle reception, yet it is
horizontally-polarized and only 10 feet up. You would think it
would look like a 'cloud warmer' in the elevation plot. Of course
it does not show quite the low angle response of a Beverage,
but for 80 and 160 the pattern certainly qualifies as 'usable'.
Although I do not understand the science, I have certainly heard
real results. If I ever move to a bigger lot, I will put up Beverages.
For now, the shorty Beverages and various loops are what work
for me.  73, David K3KY

On 13 Feb 2002 at 7:46, George & Marijke Guerin wrote:

> K3KY, et. al.,
>     Here is the matching info from W7LR for the 50 foot square
>     receiving
> loop he tried in '95.
>     73        George    K8GG