Re: Topband: Two Wire Beverage Query...

[Nick Hall-Patch <nhp@ieee.org>]

At 07:51 PM 20/08/2005, Tom Rauch wrote:


> It seems to me that I've seen some discussion about running
> a wire on the ground along the length of a beverage to
> connect the grounds between the feedpoint and the
> termination.  Is this true?>>>
>
> I can't think of a single logical reason in the world to do
> that. IMO, it is a very poor suggestion.
>
> First, the resistance of that connection would be very high
> because of soil losses.

Observations done here 8 and 15 years ago using a 600m Beverage on the MW 
broadcast band seem to verify the above statement.  Even though the DC 
resistance of the wire is naturally very low,  it was found that the 
"counterpoise" lying on the ground underneath the antenna, and connecting 
the ground rod at the far end of the Beverage with the ground rod at the 
receiver end's matching transformer, in fact, was acting like a "Beverage 
on Ground", rather than a short circuit between ground rods.  That is,  it 
delivered a signal to the grounded side of the matching transformer.    The 
result was that signal strengths often were stronger from transmitters 
broadside to the antenna (10 dB or so), the occasional solid nulls on 
signals from the back of the antenna were degraded, and little increase in 
signal strength from signals from the far end of the antenna were observed.

Those of us who performed this experiment stopped using "counterpoises" 
from that point forward, unless we used them as antennas in their own right.


best wishes,

Nick
VE7DXR

   

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