Topband: Grounded half square/half loop detuning

[Herbert Schoenbohm]

> On Thu, Mar 25, 2010 at 12:09 PM, Petr Ourednik <indians at xsmail.com> wrote:
>   
>> Hi all,
>>
>> as I received just one reply from all of You it seems to be nightmare to
>> detune
>> properly this antenna isn't it?
>>
>> Even antenna's gurus are silent...? :)
>>
>> I will be glad to get any ideas as I tried a lot but my rx ant is
>> useless still.
>>
>> 73 - Petr, OK1RP
>>
>>     
Peter,

I mentioned this before....but before detuning anything there should be 
a comprehensive and accurate determination if there is actually any 
noise contribution from the TX antenna.  Some of the gurus have done 
this but so far I have not seen any tips published.  In fact there could 
be a situation where earthing an antenna feed point could make things 
worse.  I would presume that if you placed an identical (temporary) 
Beverage several wave lengths away from your current Beverage, you could 
make some comparisons......but the issues of common mode pickup long 
feedline pickup, unless mitigated,  with W8JI's design line crackers 
from DXE, or double toroid choke rings with an independent ground in 
between, your tests might be inconclusive.

Herb, KV4FZ