KPA500 use on AM

[N8XPQ]

I am curious if anyone has used the KPA500 on AM, and what it's duty cycle  and output would be.

Mike N8XPQ

[Guy, K2AV]

AM would be less duty cycle power at 500 watts PEP AM (yes, PEP AM) than
RTTY or CW

Fully modulated AM has a peak power of four times the carrier.  That means
that the AM carrier has to be 1/4 of the KPA500's rated output, or 125 watts
AM carrier.  This is only somewhat more dense of a power pull than SSB.

You cannot run 500 watts AM carrier on the KPA500, which would be 2000 watts
PEP output, illegal in the US, and four times the rated power of the amp.

In the good old days, when FCC power regs for hams were INPUT power, carrier
was allowed to be 1000 watts input, with no mention of the modulation's
sideband power. Since the big rigs were class C with plate modulation,
giving efficiencies of 75% or better, that was 750 watts OUTPUT. Full
modulation was then 3000 watts PEP output.  Double the max SSB these days.
 1500 watts carrier would be 6000 watts PEP.

Those Johnson desk KW rigs on AM sounded loud in a way not heard since.

73, Guy.

On Sun, Oct 16, 2011 at 1:30 PM, N8XPQ <[hidden email]> wrote:

> I am curious if anyone has used the KPA500 on AM, and what it's duty cycle
> and output would be.
>
> Mike N8XPQ
>
> --
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