[Elecraft] K3 strange overshoot

[Bob McGraw]

Although my configuration is a bit different,  K3S, P3, KPA500, and 
KAT500, I see a small initial overshoot when changing bands. Drive power 
for each band is different.  PWR SET is Per Band.  TUN PWR is set for 20 
watts.   I have the amp configured to switch to STBY when changing 
bands.  I manually put it into OPER after a band change.     I attribute 
the issue to be the ALC and power control system in the radio getting 
its act together.  K3S firmware version is   uC 05.67.

Operationally, when changing bands, I hit TUNE to make sure all is well 
with the switching and tuning.  Then place the amp in OPER as the band 
change puts it in STBY.  This seems to negate the issue.

73

Bob, K4TAX


On 2/11/2022 3:06 PM, elecraft-request at mailman.qth.net wrote:
> Message: 8
> Date: Fri, 11 Feb 2022 16:43:21 +0100
> From: "Petr Ourednik"<indians at xsmail.com>
> To:Elecraft at mailman.qth.net
> Subject: [Elecraft] K3 strange overshoot
> Message-ID:<0954bd6f-61f5-4218-a22f-3b016b3ba4fd at www.fastmail.com>
> Content-Type: text/plain;charset=utf-8
>
> Hi folks,
>
> so sorry to bother you over here.
> I realized strange behavior of my trusty K3 (#778 fully upgraded, loaded, latest synths installed)
> When I tried to exciting KPA500 amp I suffered with strange overshoots during first dots.
>
> Symptoms:
> - up to 12W from K3 all is ok, over 13W the full scale deflection on KPA500 appears on first dots
> - after 1-2 dots power drops back to expected power based on exciting power level
> - the overshoot appears again after band changing or switching between OPER/STBY
> - 160m-30m are heavily affected, 20m-10m behaves better and it can be driven up to 18W but overshoot appears too (just slightly to about 600W on LED scale)
>
> Conditions:
> I realized that behavior into antennas with SWR all below 1:1.4 > no SWR protection activated at all.
> The same issue appears into dummy load.
>
> I will be happy for any kind of ideas or hints where to start...:(
> Many thanks in advance.
>
> 73 - Petr, OK1RP
> "Apple & Elecraft freak"
> B:http://ok1rp.blogspot.com
> --
> What could be easier..?  ????_?(???)?_?/??