[Elecraft] KPA500 Power In Digital Modes

[Joe Subich, W4TV]

 > No lectures on low power for JT, I run power depending on
 > propagation, or lack thereof, mostly on a dead six meter band.

Note that JT65 and JT9 are designed to be suitable for saturated
amplifiers as there is only a single tone at a time and one tone
ramps down before the next tone ramps up.  *DO NOT* try running
PSK, MFSK, etc. modes at 600W average power from a KPA-500 as you
will be generating serious IMD and garbage.

Depending on the crest factor (peak to average ratio) of the mode
in use, the average power from the KPA-5000 should be kept 6 to 10
dB below the rated maximum (e.g., 60 to 150 watts) just as a 100W
transceiver should be kept between 10 and 25 watts average.

73,

    ... Joe, W4TV



On 2014-11-10 6:56 PM, mcduffie at ag0n.net wrote:
> On Mon, 10 Nov 2014 09:34:09 -0800, Jim Brown wrote:
>
>> During KPA500 beta, I was loaned one for a major RTTY contest weekend
>> and told to run it "with all the lights lit." I did, and it worked fine.
>> In the 3-4 years I've owned one, I regularly run it at full power in
>> digital modes on all bands, 160-6M. When it gets warm, the fan speeds
>> up, but it continues to put out full power. This includes digital modes
>> like FSK441 and JT65A on 6M, and lots of RTTY on the HF bands.
>
> I'm not a contester, but have done similar with mine with no issue.  The fan
> will scream at you as it gets above 70C, but the temp levels out.  I'm not one
> to push much beyond that, as that's all the warmer it gets in JT exchanges
> running power.  No lectures on low power for JT, I run power depending on
> propagation, or lack thereof, mostly on a dead six meter band.
>
> Gary
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