> From: km1h@juno.com (km1h @ juno.com)
> Subject: Re: [AMPS] SB-220 problem
To: <amps@contesting.com>
> Date: Sun, 7 Sep 97 18:11:07 +0000
>
> On Sun, 7 Sep 1997 11:30:09 +0000 w8jitom@postoffice.worldnet.att.net
> writes:
> >The SB-220 DESIGN specs are as I indicated. Look them up.
>
> Do your "DESIGN" specs differ from the published specs in the manual?
Not so far as I know or Heathkit knew.
> I'll stick with my earlier statement thank you. BTW, try pages 79 and
> 80 in the manual and then tell me how you come up with a 600W limit. You
> must be using Rich's math.
Let's see. The maximum key down input power rating is 1000 watts dc
plate input on CW. The efficiency on a good day with a good 220 is
about 60 percent. I suspect that's about 600 watts rated CW output,
unless my math is flawed.
The SB-220 was designed to operate at 1000 watts dc plate input
power on CW, and 1000 watts meter ***indicated*** plate input
power on SSB. That was the law at the time the PA was designed,
there was never any hint the power rating would be nearly tripled
later on.
The old two kW PA's are nothing near as heavy duty as the modern 1500
watt PA's, because the rating system is very different today. I'm
sorry if you disagree with that, but it's true so far as I know from
looking at the FCC rules, equipment manuals, and engineering
specs.
73, Tom W8JI
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