[AMRadio] Re: Gates BC250L efficiency
K9AF at aol.com
K9AF at aol.com
Thu Sep 30 00:45:05 EDT 2004
hello to all:
SUCCESS!! I took a small file and carefully filed the enamel off the wire
near the hot end of the IPA tank coil/ PA grid coil, then I attached a small
piece of tinned bus wire to the end threaded connector post. I then shorted out
the first 9 turns of that coil with this small jumper. Of course retuning to
resonance was necessary, and to be honest, it didn't change the variable
capacitor a whole lot, nor did it increase the 810s grid drive more than 2 MA, BUT
I now have achieved 73% PA efficiency, which according to the Gates factory
manual is exactly what I should get, and what I was getting on 640 kc BEFORE I
converted the transmitter to 1.885 MC.
So now just a few more 'clean-up" items, and you'll hear me on 160 meters
with full AM! Thanks to all who made suggestions!
73,
Jerry K9AF
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