[Elecraft] Data transmission on 30 meters with PX3 problem

[GaryK9GS]

Hi Gwen,
Still sounds like RF getting in somewhere.  That kind of antenna is guaranteed to bring common mode current into the shack.
If you have a dummy load I would connect it directly to the output of the radio and see if the problem still occurs.


73,
Gary K9GS
-------- Original message --------From: Gwen Patton <ardrhi at gmail.com> Date: 9/1/18  10:00 PM  (GMT-06:00) To: elecraft at mailman.qth.net Subject: [Elecraft] Data transmission on 30 meters with PX3 problem 
This happens very rarely for me EXCEPT for 30 meters. Then it happens so
much, it makes data modes (CW, RTTY, PSK) useless. I'm using a wired USB
keyboard connected to the PX3. If I'm on 30 meters, and I use the ATU to
match the antenna, transmitting any data mode causes extra, spurious
characters to be added onto the end of the keyboard input buffer. In some
circumstances, it starts appending additional messages stored in message
slots mapped to function keys.

Usually it's just a few characters -- a couple of numbers, a few alphas --
that get transmitted at the end of my transmission. In less frequent cases,
the transmission doesn't stop, as new characters are being shoved into the
keyboard buffer faster than they can be transmitted. Pressing backspace to
erase these characters works very seldom, though it can help, marginally.
In very rare cases, it seems scan codes for function keys are getting
shoved into the keyboard buffer, which appends those message slot contents
to the end. I usually wind up hitting ESC to stop the transmission, because
it's running wild.

RF power isn't a determinant. I can run power down to less than a watt and
it still happens. I tried wrapping a big ferrite toroid (T200-2) with the
keyboard cable just before the PX3 keyboard port, but it doesn't appear to
help.

I've searched for solutions online and in both the PX3 and KX3 manuals. The
antenna is a half-length "W3EDP Jr."  end-fed antenna with an LDG RU-4:1
unun, run from my front porch to a tree, about 15' up at the porch end, and
about 25' up at the far end.

This is the antenna I'm using:
https://thewakesileave.wordpress.com/2016/08/15/a-42-portable-multiband-hf-antenna-with-no-wire-on-the-ground-the-w3edp-jr/

Has anyone else had this problem, or can you suggest something I might set
differently in a menu option? I've gone through about everything I can
think of, including changing the position of the coax, the aforementioned
choke on the keyboard cable, et. al., but can't figure out what's causing
this. It acts like RF getting into the keyboard. I'll try a different
keyboard while I wait for any suggestions, but other than that, I'm stuck.
Being a member of 30MDG, I'd sort of like to be able to operate on 30!

73,
Gwen NG3P

-- 

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Jenny Everywhere's Infinite: Quark Time
http://quarktime.net
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