[Elecraft] KPA1500 in CQWW CW

[Richard Zalewski]

Yes to all...

Richard
*W7ZR* ex:5C5Z, CN2ZR, K2JSP, W6SBZ, W7KXR, K9ZIJ, W9KNF, W0KDF, W0MQU,
J68ZR, KC6ZR, PJ4/W7ZR, KH2,W7ZR, KH6/W7ZR, V31ZR, VK4AAZ, XE2DV


*Be joyful in hope, patient in affliction, faithful in prayer*


On Mon, Nov 26, 2018 at 5:15 PM K9MA <k9ma at sdellington.us> wrote:

> This was my first serious contest effort with the new amplifier. It is
> paired with a K3. It survived about 24 hours of operation, though it
> faulted a few times, as described below. Clearly, the protection
> circuitry did its job. Firmware is 1.87.
>
> A couple glitches:
>
> The power gain drifts downward as the transistors heat up. If I start
> out at 1500 W, it will drift down to about 1100, without changing
> frequency or SWR. Conversely, if I turn the drive up after the amp is
> warm, and forget to turn it back down, the amp will fault when cold.
> Since the amp is talking to the K3, couldn't some clever software fix this?
>
> Despite setting tune power to 40 W, the ATU sometimes just won't get the
> SWR below 1.4:1 or so. This is with antennas below 2:1, and the ATU stop
> set to 1.0. This happens on 40 meters, so it's probably not an ATU L/C
> resolution limit. This 1.4:1 SWR is sometimes high enough to limit
> output to well below 1500 W due to high drive power or high current. I
> have not yet tried manually tuning the ATU to see if I can get the SWR
> lower.
>
> Finally, after "training" the ATU across the band, I sometimes find that
> the SWR has gone up significantly at some frequencies. I don't believe
> this is due to changing antenna SWR. It seems more like the ATU has
> "forgotten" the settings, or tried to retune itself without permission.
> (HiSWR RETUNE OFF)
>
> Has anyone else seen similar issues?
>
> 73,
>
> Scott K9MA
>
> --
> Scott  K9MA
>
> k9ma at sdellington.us
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to dick.w7zr at gmail.com
>