[Elecraft] KPA500 STBY to OPER

[Jack Brindle]

Maybe to the “Not quite as good as…” category. The issue is timing. Your code has to poll to determine the KPA op state, then start all the transitions which will result in the PTT line being negated. There are a lot of delays involved here.

With the K3/KPA, the button press causes the KPA to send the mode change data to the K3 immediately. We wait until the data transfer is complete before starting the actual mode transition. By the time it is done and the KPA is ready to go, the K3 has processed the message and switched to the alternate (KPA) power level. By the time the K3 has displayed the KPA mode change on its display it has already made the change internally.

Now realistically will anyone see a difference between the two methods? Probably not. The only real way to tell would be to start sending a CW message then tap the mode button to move the KPA to OP mode during the transition. Both methods will pick up the change, but the built-in method will do it slightly faster because of its advantage with not having to poll for the mode state change over the serial port.

Nice job with the controller, by the way. I look forward to your write-up.

73!
Jack, W6FB


> On Sep 2, 2019, at 9:46 AM, Andy Durbin <a.durbin at msn.com> wrote:
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> "It works very well. The op has to set the K3 so that the power is controller per-band. When the KPA is switched to OPmode, it sends a message to the K3. The K3 then switches to the amplifier selection for power, which the op has set specifically for the KPA."
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> Jack,
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> I'd love to see the worst case system timing diagram for that but I know that's not likely.  Either the [KPA500 state]>[K3]>[K3 power control] is very fast or the KPA500 does not fault as fast as I though it did.  Perhaps both?
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> So, no KPA500 fault, no power spike, and no damage when KPA500 is switched to OPER when K3 is transmitting with 100 W output.  I'll have to move that one to the "good as" list from the "better than" list if I even do a write up on my TS-590/Elecraft controller.    "Good as Integrated K3/KAT500/KPA500" was a top level system requirement.  "Better than"  was just nice to have.   
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> 73,
> Andy, k3wyc
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