Posted by
Lyn WØLEN on
Nov 23, 2020; 10:34pm
URL: http://elecraft.85.s1.nabble.com/KAT500-Anomalies-tp7666427p7666434.html
Thanks, Rick. I try to pay attention to all those points, and really haven't seen this behavior until today.
I still find the distinction between Auto and Manual modes a little fuzzy. Are you doing the "teaching" in Auto mode, but saying that operating should be in Manual mode ... like I think you're saying? Do you change the default setup, which has both boxes checked for QSY re-tuning?
And then this:
" Then you put the tuner into manual mode; which still adjusts the matching values as the frequency changes BUT disables the retune feature. "
How does it adjust the matching values without retuning? Are we saying just tiny little baby-step fine tuning? Or am I getting caught up in semantics?
73
Lyn, W0LEN
-----Original Message-----
From:
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[hidden email]] On Behalf Of Rick Bates, NK7I
Sent: Monday, November 23, 2020 3:33 PM
To:
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Subject: Re: [Elecraft] KAT500 Anomalies
The short answer is you 'teach' the tuner on each 'bin' frequency what
the settings are for a good match (with each antenna, each on it's own
antenna port). Then you put the tuner into manual mode; which still
adjusts the matching values as the frequency changes BUT disables the
retune feature. You DO need to pay attention to SWR, that should be
second nature anyway.
Every time you 'teach' a value into the bin (one per antenna port), it
overwrites the previous value(s) so no, you won't run out of memory.
One thing I would do is check the tuner component values from your
baseline (dry, sunny day) to the current values, it's possible that
something is changing on the antenna more than usual (ladder/window line
DOES change a little when wet or windy and near other 'things'). If the
changes are small, you'll be fine. Any major shift in values (or SWR)
should be evaluated for cause (broken wire opens when windy?).
I suggest that you limit the amount of feedline movement, if possible (I
tied mine with a cord, to the fence, then it ran to the shack, slightly
tensioned just enough to compensate for tree movement, not free sway).
That reduces the seasonal affects.
You could also compare un-tuned SWR to see if there is a radical change,
but SWR is not the entire story of the load (it's a composite measurement).
Of course, make sure that your matching device (balun has variable
meanings making that name, useless) has tight, clean weather resistant
connections and isn't bothered by weather or seasonal debris (leaves).
I came across similar changes when I used a 375' center fed dipole (80M
EDZ) at only 35' (oaks didn't grow much taller), window line fed into a
4:1 common mode choke transformer and a SHORT piece of coax into the
shack. It worked well on all bands, I managed over 200 countries
despite the local noises (noise floor ~-80 dBm). Now I use a resonant
antenna (80-6M plus one on 160M) which is MUCH simpler (but expensive)
with a noise floor typically in the -120 dBm range (ah, quiet! I moved
away from the noise).
73,
Rick NK7I
On 11/23/2020 12:52 PM, Lyn Norstad wrote:
> I've been using the KPA/KAT500 Combo for a bit over a year, and while there
> have been a couple issues with the KPA, the KAT has been fine for all this
> time. I operate various digital modes frequently (i.e.: FT8, JS8, Winlink,
> etc.) so I often return to the same frequency on each band.
>
>
>
> Today, running 50 watts in Winlink VARA HF mode, it had problems staying
> matched on 80 meters. It would try to rematch on each transmit cycle.
>
>
>
> As a result, the cycles were incomplete and data transfer was erratic.
>
>
>
> My question is, how many memory settings can it hold in memory, per band?
> My antenna is fed with ladder line (yes, I have a balun, etc and it's been
> fine for well over a year). It's possible that the system will tune
> slightly different now and then due to the ladderline blowing around (in
> contact with tree leaves, let's say). Am I using up so many memory slots
> after this time that it is running out of space?
>
>
>
> Thinking that might be a possibility, I reloaded a config from about 6
> months back which would not have seen as many frequencies used. I have also
> experimented with the MTA commands. At this point, it seems stable.
>
>
>
> I've always been a bit confused by the "Teach it in Auto Mode, but Operate
> in Manual Mode" suggestion I've heard from time to time. As received, the
> "Memory Recall Tune on QSY" defaults to ON for both modes.
>
>
>
> I'd appreciate any insight from KAT users.
>
>
>
> 73
>
> Lyn, W0LEN
>
>
>
>
>
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