[Elecraft] XV mods

[Geoffrey Mackenzie-Kennedy]

John,

Would external coaxial notching filters be practical for you? Another 
thought (perhaps easier to implement) is an added small relay in each 
transverter to RF ground the PHEMT's gate (or antenna connection) in the 
unselected transverters. This would avoid the increase in noise figures 
caused by the insertion loss of added bandpass filters. I don't have the 
circuit diagrams to hand to see if the capacity between open relay contacts 
would upset things when connected to the selected PHEMT's gate or whether it 
could be tuned out.

73,
Geoff
GM4ESD


----- Original Message ----- 
From: "John D'Ausilio" <jdausilio at gmail.com>
To: "Elecraft Mailing List" <elecraft at mailman.qth.net>; 
<VHFcontesting at contesting.com>
Sent: Tuesday, March 20, 2007 12:52 PM
Subject: [Elecraft] XV mods



> I run a stack of 4 XVs driving high-power TE amps in my rover.
> Antennas are short yagis spaced relatively close to each other on one
> mast. I've experienced failures of the PHEMT due to the large amount
> of RF present on the unselected transverters, whose configuration
> leaves the gate of the PHEMT connected to the antenna connector in
> that state.
>
> I suspect bandpass filters would probably eliminate the problem (I
> have one on the 6M, but space is at a premium