[K3] KAT3 algorithms?

[Randy Moore]

I am puzzled by how my KAT3 is working.  (FW 4.39/2.73)  Just now, I was
chasing some DX on 20m.  I was listening on 14.020 with split up to
14.022.5.  I called once and noticed the SWR was up around 3:1.  That's
ok, but I wanted to get it down a bit, so I killed split, moved VFO A
down to a clear frequency near 14.018 or so, and hit ATU TUNE, which
produced an SWR of 1.0:1 at 5w.  Then I used my spotting program
(DXLabs) to put me back on 14.020 split 14.022.5 and called again.  SWR
was back at 3:1.  I repeated the process and got the same results
again.  So then I went up to 14.023 with VFO A and did he ATU TUNE, and
all was well with the SWR at 1.0:1 transmitting on 14.022.5. So then,
using the TUNE button, I check the SWR back down at 14.018 and it was
1.2:1.  So, why was the original ATU TUNE at 14.018 not good enough at
14.022.5?

After going through the tuning process at 14.023, I can no longer repeat
the original process.  everything in the vicinity of 14.020 +/- 5kHz is
1.2:1 or less.

Is there a description of the KAT3 algorithm somewhere?

Also, I've wondered how the ATU memories are allocated across bands, and
how many there are.

73,
Randy, KS4L
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[John Oppenheimer]

> 1.2:1.  So, why was the original ATU TUNE at 14.018 not good enough at
> 14.022.5?

My guess: the ATU memory transition is at 20Khz steps. I have wondered
where they were. You may be able to repeat the process if you clear out
the band's ATU memories, see the "KAT3" configuration option, the last
description line, "Tapping CLR within this menu entry clears......"

John, KN5L
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[John Oppenheimer]

Randy, I found the ATU memory step spacing in the Firmware Release Notes.

In release notes for MCU 3.03 / DSP 2.10, 3-17-2009:

* MULTIPLE KAT3 ATU DATA SEGMENTS PER BAND/PER-ANT.: 10 kHz
per segment on 160 m; 20 kHz on 80-12 m; 50 kHz on 10 m; 200 kHz
on 6 m.

John, KN5L
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html