Hi all, success at last...I am happy to report that I have finally
sorted out the bugs which were causing me much angst with my new GS-35B
160 meter amplifier....Put down most of the trouble to my own errors
when constructing it...
For some reason unknown to me I had the pi input network way off
resonance and after finally sorting this out this morning everything
started acting normally...
The running conditions are now as follows...with 75 watts of carrier the
amplifier easily produces slightly over 1000 watts out....Increasing the
drive to 95 watts carrier the power output is 1400 watts...Anode current
for 1000 watts is just on 800ma and loaded heavily into 50 ohms, grid
current is 205ma....The tube runs reasonably cool at the 1kw output
level....As I am using a new Ameritron AL-80B power transformer I intend
keeping the amplifier at the 1Kw level....Measuring voltage drop with
1KW output the HT drops from 3.1KV to 2.7KV....Increasing the power
output loads the anode voltage down drastically..Not worth the risk of
damaging a good transformer and at the 1KW power output CW the tube is
barely working hard, stays reasonably cool and should last for a long time..
I intend to turn up an adapter for the GS-31B tubes so that I can fit a
GS-35B cooler to the 31B...I have tried the 31B tube in this current
linear and although it is a willing worker, at 1Kw output it gets quite
hot with my air system..
For those of you using the GI-7B tubes, I replaced the coolers on those
tubes also with coolers from GI-46B tubes....This made an immediate
difference removing the heat from the tubes...
Thank you to all who gave me suggestions to sort this amplifier out...I
am grateful and learned a few new things about amplifiers...
73....Bob VK3ZL..
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