[Elecraft] KPA500 Band Tracking

[Jack Brindle]

You have found the problem by now, but let me comment on some other areas. The only place in the KPA500 that is restricted is the US FCC-mandated CB frequencies of 26 to 28 MHz. If you really want to output 600 watts on 30 meters (as is allowed in some areas) go right ahead. It won’t operate below 1.6 MHz because of limitations in the frequency counter code (making sure the counter is functioning properly), and above 54 MHz it probably won’t do all that much as the 6m bandpass filter does its work.

The KPA listens to the BAND0-3 inputs for band determination. It will change bands pretty much immediately on seeing those input signals change. It also counts the input frequency and will switch bands if the count shows a different band - and will ignore the band inputs to use that band until they change again. So even though it detected something other than the combination for 40 meters, it would have gone there on TX and stayed until you later changed bands.

Lastly, what Don was referring to - pressing a band button on the KPA500, when the RADIO is set to K3, will send a request to the K3/K3S to go to that band. When the K3 responds by changing bands, it will output the proper combination on its BAND outputs, which will then cause the KPA to itself change bands. In other RADIO settings the KPA will immediately change bands, but not so with the K3 setting.

Hope this helps. Those AUX cables can be pesky at times - make sure none of the pins are bent, and that everything is connecting properly. And, as we have said many times, do not use a VGA cable unless you are absolutely sure it is full 15-pin straight through, since most VGA cables connect several pins together as grounds. Me? I fabricated my own cables for my station, but then I have the facilities to do so…

73!

Jack Brindle, W6FB



> On Aug 7, 2016, at 5:21 PM, Dauer, Edward <edauer at law.du.edu> wrote:
> 
> I appreciate your having written, Cliff; and it is the case that 30 meters is an oddball.  Just as the K3 is booby-trapped to prevent transmitting out of band, it could very well have been that adding 30 meters to the working bands would have required some special consideration to keep the amp from violating the power limitations.
> 
> Thanks again,
> 
> Ted, KN1CBR
> 
> 
> On 8/7/16, 6:10 PM, "Cliff Frescura" <cf at cfcorp.com> wrote:
> 
>    I think I jumped the gun and was wrong.
> 
>    73,
> 
>    Cliff K3LL/6 
> 
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> 
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