[Boatanchors] Hallicrafters SR-400 RF Output ???

wd0x at adelphia.net wd0x at adelphia.net
Fri May 5 20:11:15 EDT 2006


I'm hoping someone familiar with the proper operation of a Hallicrafters SR-400 Cyclone transceiver (paired up with a PS-500A-AC supply) can give me an idea of how much full rf output (not input) in watts in the CW position is "normal" into a 50 ohm dummy load. I've been fiddling with one that has a new pair of, idle plate current matched and neutralized, 6JH5 finals and a good driver tube. 

Best I can get on 80/40/20 meters is 150 watts CW output @ 350ma plate current. Output too low? About right? PS-500A-AC has been completely rebuilt and all voltages (800vdc, 280vdc, -125vdc) & idle plate current (70 ma) are correct. All caps and resistors in the PA circuit are OK. I'd really appreciate some expert opinions/advice before I go any further.

By the way... Anyone have a better method of neutralizing these finals besides the procedure outlined in the manual? Somehow adjusting the neutralizing cap with full plate and screen voltage on both finals seems like a great way to shorten the life of these nervous sweep tubes!  I have an Autek RF-1 antenna analyzer that can transmit a weak signal to the PA stage. Seems like I did that once a long time ago with a Johnson Valiant. Don't remember how I did it, hi........ Hmmmmmmmmmmmm

Thanks, 73, Bill, wd0x


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