Topband: Two wire Beverage Question

ZR zr at jeremy.mv.com
Tue May 22 08:28:48 PDT 2012


>
>
> I recently measured Gary's 2-way boxes and they are good (virtually flat
> freq response) to over 21 MHz..
> Unfortunately my 200m 2-way is down on 3.5MHz in reverse direction, and 
> also
> deaf on 7MHz probably because total transmission line losses are over 20dB
> on that band. Plus earth and transformer losses another few dB.
> (I was thinking of trying a remote preamp).
> 73
> John G3PQA
>


How was that measured John? On the bench can miss a lot and flat to me 
outside usually means excessive loss.
Im using WD-1A, WF-16/U, and 2 wire rural telephone cable which is 
copperweld.

Listening on 40 a few minutes ago shows no particular loss but very sharp 
directivity. The directivity really knocks local crud right into the noise 
floor and the band sounds dead but signals are loud with fantastic SNR..

RG-6 up to about 150' feeds the switching box and then 750' of 1/2" CATV 
hardline back to the house. A preamp is available but hasnt been needed 
since the rebuild started 2 years ago.

Transformer cores are all BN73-202 with primaries and secondaries isolated 
in individual Teflon tubing for minimal C coupling.

Carl
KM1H




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