KX3 - Strange Behaviour

[Kurt Pawlikowski]

Good morning!

     Sorry for the length of this post: Its a bit complex and I needed
to let people know that I *think* I know what I'm talking about! {'-) k

     Well, while Field Day 2018 is now in the past, I am having some
concerns about my KX3. This is a little hard to explain, but here goes!

     Our setup was in, unfortunately, a fairly high noise area. I was
working 20 CW. The noise level was S3, with times reaching S6. I
believe, "normal" would be closer to S1. And, of course, lots of signals
all over the board signal strength wise. Many of them very strong (10 to
20 over 9!). Also note that this unit has the crystal filters and ATU. I
also have the KPA100, which also has the built in ATU. I upgraded the
KX3 software to the latest just last week in preparation for FD. Okay,
that's the setup. Here are my observations:

     First, my KX3 has "some" opposite side band bleed through. On 20
CW, I believe it is using the equivalent of lower side band (as you tune
from higher to lower frequency, the CW notes go from "high" to "low").
As you pass through zero beat, on reasonably strong signals, a "ghost"
signal can be heard going from "low" to "high", but it is very
attenuated. This is what I consider "normal" (or perhaps "average")
operation for a KX3 as configured. But, there's more...

     I started to notice that, as I was tuning "down" the band (from
higher frequency to lower), there were several "artifacts" (for lack of
a better word). First, the several things I noticed were "in sync" with
the expected behavior of pitching from "higher" to "lower" as I tune the
Rx frequency from "higher" to "lower". So, as far as I understand,
/_not_/ opposite side-band "bleed-through." The first artifact seemed to
mimic a signal, but it had a distinct difference, which I'm at a bit of
a loss to describe. Let's just say "muffled," though that's not
accurate. If I remember correctly, it was always a strong signal and
seemed to shift with changing frequency properly. I could recognize it,
so at least I knew it and could ignore it. Now for the coup d'etat...

     I also noticed that I was apparently receiving "ghost" signals that
were about 500 (or so) Hz between. These signals seemed identical to
each other. With the large number of signals on the bands, my bandwidth
was narrow - between the tightest (I believe 50 Hz?) and a maybe 1 k.
This is the artifact that bothers me. I have no idea which one was the
"real" signal (like something from the old "What's My Line" TV show!).
So, here's my question: Has anyone noticed something like this before?
Is this some sort of configuration issue or is it hardware, or maybe
it's just me (!). I don't know if I can reproduce it, so...

     Anyway, any input is appreciate it. Thanks!

     kurtt,

     WB9FMC

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[Brian Hunt]

Did you have the NB on?  I've noticed on my KX2 (similar h/w and firmware) that using the NB with very strong signals close by will create all sorts of artifacts like CW being sent using a highly damped bell. Turn off the NB and it's clean as a whistle. HTH

73,
Brian. k0DTJ

>    Our setup was in, unfortunately, a fairly high noise area. I was working 20 CW. The noise level was S3, with times reaching S6. I believe, "normal" would be closer to S1. And, of course, lots of signals all over the board signal strength wise. Many of them very strong (10 to 20 over 9!).

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[Kurt Pawlikowski]

Brian,

     We were in a high noise area and yes, I had the NB on. {'-) I
suspect that was the "muffled" artifact I was getting, but the "ghost"
signal, I'm not so sure about! {'-) All I know is that I'd call on one
of them, and they'd usually answer. Sorry I didn't pay any closer
attention to the spacing and such. Might be a clue for someone
attempting to eliminate the issue!

     k WB9FMC


On 6/27/2018 10:40 AM, Brian Hunt wrote:

> Did you have the NB on?  I've noticed on my KX2 (similar h/w and firmware) that using the NB with very strong signals close by will create all sorts of artifacts like CW being sent using a highly damped bell. Turn off the NB and it's clean as a whistle. HTH
>
> 73,
> Brian. k0DTJ
>
>>     Our setup was in, unfortunately, a fairly high noise area. I was working 20 CW. The noise level was S3, with times reaching S6. I believe, "normal" would be closer to S1. And, of course, lots of signals all over the board signal strength wise. Many of them very strong (10 to 20 over 9!).
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

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