Thursday 11th May
Thanks to everyone who replied to my posting - lots
of helpful information,ideas and different designs.
I'll collate all the responses and post them on my
web-pages www.qsl.net/gm3woj/
as soon as things are back to normal at qsl.net.
My thoughts after having studied the information are:-
1. With 4CX1000A, 4CX1500B and 8877 amplifiers,
50MHz is approaching the max. frequency for using a
Pi or Pi-L circuit. (I have a 2 x 4CX250B amp. which
uses a Pi tank on 70MHz - just!)
2. 'Established' 50MHz designs are not so easy to
repeat in practise - many are very component-specific,
layout-specific and/or operating-conditions specific.
Even using identical components, layout and operating
conditions does not guarantee that the amp. will behave
as expected. Some designs seem to work by good luck
rather than good design.
These are pretty obvious statements I guess ! I've now
got the tank circuit to resonate, but efficiency is only 48%
so I've quite a few improvements/changes to make.
(There is no DX to work on 6m from here at the moment!)
Look for some photos of this 6m amp. and other amps.
on my web-pages soon, and also check www.gm7v.com
73
Chris GM3WOJ
gm3woj@talk21.com
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