Date: Mon, 05 Dec 2016 21:31:54 -0800
From: Paul Baldock <paul@paulbaldock.com>
To: "Jim Thomson" <jim.thom@telus.net>,<amps@contesting.com>
Subject: Re: [Amps] The cost of amplifiers, radios
My main amp is an ACOM2000A. But when I need instant on for a QUICK
qso I use my backup amp the L4-B. I run 3400V on the plates in the
L4-B and comfortably get 1500W on SSB and CW. I have the original
cooling fan, so I do not use it for RTTY.
I have no interest in cheating and running more than the legal limit.
By the way for those that don't know, our legal limit on 30M is 200W PEP.
- Paul KW7Y
## I wasnt advocating cheating. After talking to Ted henry back in the day,
he told me at the time that the rebuildable 3CX-3000A7 was a mere $50.00 more
than
the throw away 8877. He was correct of course. The 3CX-3000A7 is still a
bargain vs the
8877. -59db pep IMD3 is nothing to sneeze at....provided the xcvr is up to
the task..and most are not.
## still, the 3CX-3000A7 is easily driven to 1.5 kw out with just 50 watts of
drive. Most 100 w
xcvrs will have good imd when run at 50 watts out. Ditto with any 200w xcvr.
My yaesu mk-V
runs a max of 75 w pep out, when run in class A. Run at 50-75 watts out,
thats as good as it gets.
## legal limit here in canada is 2250 w pep out... measured at the ant.
Assuming .5 db loss... 10%,
I require 2.5 kw pep out of the amp... to get 2250 pep at the ant. An
expensive 8877, not rebuildable, run
at 2500w out is pushing the 8877 to its absolute max ratings, like 4 kv under
load at 1A..and 62.5% eff.
And you wont get high eff on the upper bands like 10 + 12m.
## at the time, I felt it was more cost effective to just spend the extra
$50.00 on a better triode.
## On 30M band, we are restricted to 750 watt out... again, measured at the
ant. Max 1 khz BW,
so only CW + data modes allowed.
Jim VE7RF
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