[Elecraft] KPA500 - just 500 watts?

k6rb at baymoon.com k6rb at baymoon.com
Tue Jan 25 13:16:54 EST 2011


The question of "how much power is enough?" is always good for a lot of
chatter. Yes, an extra S unit requires 6 dB more power. Under some
conditions, if 100 w gets you to S7, then dumping in enough power to get
you to S8 is a case of diminishing returns. But, if 100 watts gets you to
S3 with ambient noise hovering between S2 and S4, then that extra S unit
can make the difference between making that contest Q or getting that new
country.

Emotionally, it's hard to grok that going from 500 watts to 1500 watts
makes scant difference in what's heard on the other end of the circuit. I
know that there are rare cases where cutting back from 1 KW to 500 watts
reduces the R from a 5 to a 4, but usually it makes no difference.

After a zillion years of running 100 watts or less into random lengths
strung out of windows, I got my first yagi in 1981, and my first amp - an
Ameritron AL-80 (the very first one with quasi-QSK built in). It put out
about 700 watts, comfortably, and with the TET 4-element/triband yagi, I
felt indominitable. Pile ups? No problem. Contest score surges; big time.

Since then, I've spent considerably more on tower, yagis, SO2R radios and
amps, and I've never felt the same sense of differentiation as when I
first got a yagi and an amp.

Right now, I have a Alpha 87A and Ten-Tec Centurion. I never run either
above 1 KW. When the KPA-500 comes out, I'm inclined to put it in place of
the Centurion and see how it plays. If I see little difference, I'll
probably put the Centurion on the shelf, or sell it. If the difference is
really scant, I may do the same with the Alpha. I already have 240 at the
rig desk, so that's not an issue.

I have been hesitant to go solid-state QRO because of the horror stories
I've heard about amps blowing up. But, I don't think Elecraft will put an
amp on the market until they believe it's reasonably bullet proof.

My dos centavos,

Rob K6RB



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