[Kenwood] VOX on 520S

[John M. Trindle]

I hooked up a laptop computer to the phone in/out jacks on the back of my
520S on Saturday, set up VOX mode, and started running Digipan doing
PSK-31.  Everything worked terrifically, except that I could trigger the
VOX with very loud noises, like coughing.

(yes, my mic was turned off with the switch on the mic itself, and the
computer mic was muted in the mixer control panel).

Anyway, that's not the problem.  The problem is, when I got home after
taking my Element 4 exam, I was ready to get back into PSK31.  The VOX
didn't work as expected.

1) When I used Digipan normally the VOX wouldn't switch, or would switch
for a split second and go back to receive.
2) When I used the mike normally, I had to get right up on it to make the
VOX switch, with my hands cupped around the mike.
3) When I used Digipan's "tune" option, the VOX always switched properly.
This option just generates a pure tone with no PSK31 modulation, I think,
at a pretty good volume.

The VOX gain and anti-VOX gain were on full, and the VOX delay was as
well.  I tried adjusting these controls. The mic gain was at about 2/3,
which is where it works well for straight PTT operation.  I tried
adjusting this as well.

oh and

4) Regular PTT phone operations from the mic work fine.

Is it possible that I have done damage to the VOX circuitry?  Can it have
a transient problem?  It was working so nicely for PSK31 (I didn't really
like it much for phone).  Does the ALC setting matter for VOX operation?

Oh, there were some strong incoming signals at the time but I experienced
the same results when switched to the dummy load (eliminating signals
which might trigger the anti-VOX).

Thanks for any advice you can give.

-- 
John M. Trindle KG4RZH
http://i.am/jtrindle
"The Unapplicable Law:
   Washing your car to make it rain doesn't work."