[Elecraft] KPA-500 in Contest Conditions

[Robert G Strickland]

I can add a few cents to this one. I've used the KPA500 in the usual big 
and in some of the small contests. It works transparently. When running 
stations on cw, the temp tends to rise to the mid-to-high 30's C. While 
I have no doubt that the temp sensitive fan would speed up to meet the 
challenge, I always increase the base fan speed when I know the temp 
will be going up, usually to the #4 speed. I believe in prevention 
rather than wait for the cure. The fan is loud at #5/#6 speeds. However, 
I'm always under the headphones, so I don't hear it at all. The only way 
to reduce fan noise would be to use a bigger fan, and that wouldn't be 
consistent with the small form factor for the amp. In all, it's a nifty 
500w amp that I can live with for the duration. And, needless to say, 
it's backed up by Elecraft and this list. IMHO, these last two factors 
place it head and shoulders above the rest.

...robert

On 7/13/2013 17:59, iw1ayd - Salvatore Irato wrote:
> Hi all.
> The KPA is a good performer. Even when it get at 70C temperature, it
> doesn't crank down the power.
> It's noisy that's right compared to no noise there is some when it is
> hot. But with my previous experience with a 1K-FA by SPE it is much
> silent than that. Power is comparable in between the two is comparable,
> as the SPE have the specification for RTTY at the same 500W as the
> KPA500. But the SPE loose power over time, the KPA500 instead doesn't
> lose any power.
> It maybe that the noise of the KPA500 is much better as Elecraft use a
> big fan, that when scream have a lower pitched tone the the SPE. The SPE
> use 8 smallest fan, it have inside much more modules, 3 instead of one,
> of the KPA500.
> That's why I switched over the two to the Elecraft one amp and I am not
> regretting it.
>
> Activity here is substantially only in RTYY: DXing doesn't produce any
> remarkable noise; Contesting RTTY make it sounding for sure. But way
> better than my older one SPE. You could survive without headphone with
> the KPA500.
> I have engaged several times the overtemp protection in the SPE in over
> 4 years of use. I tried to engage the same protection on the KPA500,
> RTTY Contest CQing cycle, but after fifteen minutes at 70C I stopped the
> test. That's not a scientific and repeatable test, maybe, but it's quite
> enough for me.
>
> I don't have a great station here at home but sometime RTTY RUN times
> are really interesting as it was on the latest DLDX and before on one of
> the 75 baud contest.
>
> Take care also that the late season was 28C to 35C, it's pretty hot here
> down with relevant humidity. I am speaking of almost one month since the
> switch of the PAs.
>
> For serious RTTY Contesting at legal power limit I would use a vacuum
> tube PA.
>
> Not to mention one sure thing, the way as the KPA500 is engineered leave
> all the space for a great serviceability. It's not the same for several
> other SS PAs.
>
>                      73 de iw1ayd Salvo
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-- 
Robert G Strickland, PhD ABPH - KE2WY
rcrgs at verizon.net.usa
Syracuse, New York, USA