I use only SS transceivers myself as well as other users of amps which I had
my hands on.
The return path for the RF current is closed already via the cable
capacitance between linear and transceiver or IPA.
The shortest cable is 6m long, some are much longer.
However, the input resistances of the tubes used in the amps are all between
40 and 70 ohms.
Most are 3CX3000A7 in modified Henry 3000D decks, others 2-3 QB5/1750 in
parallel.
73
Peter, DJ7WW
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Jim Thomson
Sent: Montag, 24. September 2018 11:49
To: amps@contesting.com
Subject: [Amps] PASSIVE NEWORK CATHODE INPUT
Date: Sat, 22 Sep 2018 20:10:49 +0200
From: "Peter Voelpel" <dj7ww@t-online.de>
To: "'Jim Thomson'" <jim.thom@telus.net>, <amps@contesting.com>
Subject: Re: [Amps] PASSIVE NEWORK CATHODE INPUT
<I dont see a reason for it.
<And I make no use of it with my GG amps.
<I dont use a passive input neither with GG amps, only with grid driven
<tetrodes.
<73
<Peter
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Jim Thomson
## You want some flywheel action with a tuned input..and a passive input
wont provide that.
............................................................................
......................................
#### Ok, so you dont use either a passive input nor a pi input, nor
a T input.
I have not had much luck driving the cathode directly when using a SS
xcvr.
Follow the return rf current of the GG triode tube. Without a PI input,
the
only return is via the braid of the coax back to the xcvr, through one of
the caps
in the LP filter, then back down the center conductor of the same coax,
completing
the loop.
## I use what works. I don't have any tube type xcvrs anymore.
Jim VE7RF
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