I'm new to tuning HF amateur amps. I've tuned a lot of tube VHF and UHF amps in
amateur and commercial service. I tuned a fair number of tube HF amps in the
military (including Collins S line at MARS stations).
It could be that I'm not use to the way this thing tunes. I'm use to seeing a
real dip when something is in tune and finding a place in the loading control
that is optimal for loading. This thing seems to be really broad tuning. I can
see the peak in the power when I get the dip in plate current. The loading
control doesn't seem to make a big difference anywhere seems to be as good as
anywhere else. It seems easy to get 1500 watts out of this thing so I don't
think the tubes are flat.
I noticed that the amp takes no where near as much drive as the manual
indicates it should to get to the max power level.
Maybe I'm on the threshold of RFI problems at 100 watts barefoot but I go from
no problems at all to getting into everything in the house when I go from
barefoot to even 500 watts through the amp. I know from experience there are
lots of ways to fool a wattmeter and if it weren't for the fact that there is
very little reflected power into a resonant antenna I'd suspect that the amp
was being a 500 watt comb generator.
I bought this amp used a few weeks ago and really don't know it's history.
I'd like to hear from other owners about their experience with this design. I'd
buy dinner for someone in the S.F. Bay area who has one of these who would come
and look at mine and advise me on it.
73, Bill
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# Bill Putney - WB6RFW | My repeater:443.400 Mhz-100 Hz #
# WWPC | It's not open, it's not closed,#
# 5780 Balmoral Drive | it's controlled. It's open for #
# Oakland, CA 94619 | membership (which is free...). #
# billp@wwpc.com - (510)531-2412 | Go figure... #
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