It didn't help that in this particular case (a mil product, too) they uprated
from 350 watts to 900 watts on CW by changing tubes, filament and HV
transformers, but not the ceramic tuning caps......or providing tube
manufacturers rated airflow across the tube socket, either.
Pye Telecommunications in the UK were reputed to clip out bypass caps until it
started oscillating, and then replace the last one. However, production
tolerances can play merry hell with that approach, and it costs a lot more to
fix a batch of oscillating IF strips than to put the extra few cents worth of
components in in the first place. But the beanies don't understand that.....
until it happens. I've known companies who have asked for a batch of ICs to be
selected to be at the low gain end of the spread because they didn't follow the
applications recommendations (to save money, of course) and the circuit
oscillated with ones at the high gain end. And the other way around.
73
Peter G3RZP
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