Topband: Loop on the ground as a counterpoise

[Roy Koeppe]

Reminiscent of the DDRR antenna?

73,  Roy   K6XK    Iowa


On 5/4/2020 3:57 AM, Chris Moulding wrote:
> I've developed a High Z Antenna Amplifier for 160m and other HF use as 
> previously mentioned on the list.
>
> Usually these would be used with a ground rod and 5m vertical element.
>
> With the lockdown it's not possible to nip to the shops for a ground 
> rod so I looked at supplying a 10m wire as a counterpoise.
>
> At home and the workshop I have Loop on the Ground antennas from 
> previous antenna experiments so I also tried using these with both 
> ends of the loop connected to the amplifier ground terminal.
>
> On testing this gave significantly better signal to noise ratios than 
> using a ground rod or a single wire counterpoise. Checking with a SDR 
> receiver I could see that the usual local VDSL internet hash had 
> disappeared.
>
> Both loops on the ground are 3m or 10' square.
>
> I've also tried it using a G7FEK vertical antenna at home with two 3m 
> or 10' square loops on the ground with similar results seeing much 
> reduced local noise compared with the ground radials I had before. 
> Topband Dx might be a possibility for me now.
>
> I've never seen this mentioned in ham magazines before and I can't 
> find anything with an internet search. Usually I find that all my good 
> ideas have already been thought of 50 years ago.
>
> I suspect that the RF voltage in the loop counterpoise is much reduced 
> over the voltage at the end of a radial wire reducing noise pickup in 
> the radial system.
>
> I would like to model the loop on the ground counterpoise in a 
> modelling tool. I use 4NEC2 but only have access to NEC2 so wires on 
> the ground don't model correctly.
>
> Is there any one out there with access to suitable software that could 
> model it for me?
>
> 73, Chris G4HYG
>
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