Folks,
Well I finally took delivery of my Drake L7E yesterday. Up against
my HB efforts, I'm amazed at how small the thing is, yet it makes 1kW
OK, at least on 80 m.
Many thanks to all those that provided me with mod. info by direct
mail. There are certainly a number of less than clever aspects to
the L7's design - I particularly love the bias divider silly in the
HV PSU that makes the thing boil its nuts off before the amp.
actually pulls any anode current! All the issues are fixable,
however and, with the PSU being separate, there's plenty of room for manoeuvre.
So far, I have one question on those familiar with the innards of the
amp.: When I lifted the lid, prior to plugging it in, I noticed
something that struck me as odd, namely the orientation of the plates
on the load 'capacitor'. I can understand why the designer chose to
use a split-gang capacitor, however I would have thought that the
plates in each of the two gangs should be in mesh by the same amount
for any given rotation of the shaft? On my amp, the plates in the
two gangs are close to being at 180 degrees with respect to one
another - i.e. when the one gang is coming fully into mesh, the other
is headed towards being fully unmeshed. With both gangs paralleled
electrically for the low bands, which way should I turn the load
control to load heavy? Perhaps there is a nut on the shaft somewhere
that needs attention - any ideas?
Regards.
Mark.
*******************************************
Mark Hill - G4FPH
E-mail: g4fph@mjha.co.uk
Current web pages at: www.g4fph.net
Old web pages at: www.qsl.net/g4fph
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Dipoles resonant on 1940 / 3700 kHz
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Remember - SIDE for HV safety:
S witch off
I solate
D ump
E arth
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