[Elecraft] K3: Loss of rx signal

[Stewart Baker]

Rick,
In one way I am sorry to hear that you have a problem with 
occasional loss of RX after TX, however I am pleased that I am now 
not the only one to report this problem !

I was hoping that the new F/W releases would rid my K3 of this 
annoying phenomenon, but that did not happen...

I have a sequence which I can use to reproduce the loss of RX, and 
you might like to try it.

POWER
80m LSB 3780
NOR
LO CUT=0.15
SAV ALT1
NOR
TX ON/OFF
ALT1
TX ON/OFF
Receive may be dead at this point

If not continue with
Select USB
ALT1
TX ON/OFF
Receive dead

Of course Y.M.M.V.

73
Stewart G3RXQ

On Sun, 4 May 2008 20:51:52 -0700 (PDT), AI1V wrote:
>
> When running some CW contacts on 40m, I had the unpleasant 
experience of
> having the rx go almost totally dead (very low noise level - no 
signals)
> immediately after calling a station.  Nothing seemed to recover 
it so I
> power cycled the radio in time to hear the other station send 
..--..  This
> happened a couple more times.  I hadn't notice this happening 
before.  The
> only new thing I had recently tried was the ALT1/ALT2 filter 
settings
> (pretty cool feature).  While it is somewhat unpredictable, the 
phenomenon
> appears to be strongly correlated with the use of this feature. 
 I have also
> found that I can recover from the "dead rx" condition by 
tweaking the shift
> or sometimes the width, but sometimes that doesn't work and I 
need to power
> cycle.  Since then I've stopped using ALT1/ALT2 and haven't had 
it recur.
> Note: this problem appears in the new firmware as well as the 
last revision.
>
> On a possibly related note - I was running the hi and low power 
tx gain cal
> procedure after updating the firmware.  By mistake I spun the 
width knob
> instead of the pwr knob to adjust the power.  At some point the 
filter setup
> got quite hosed - the width display showed around 4 khz, but the 
passband
> display was at minimum width.  The next time I tried keying 
(holding tune) I
> got the nefarious ERR TXF message!  I also noticed that the 
noise level on
> the rx was way down (I was connected to a dummy load) from where 
it was
> earlier.  Power cycling the radio brought everything back to 
normal and I
> completed the cal.
>
> It appears that something is whacking filter parameters in the 
DSP - or at
> least that's what it's acting like.  I've reported this to 
support at
> elecraft.
>
> Nevertheless, the radio kicks butt.  The mojo is alive and well 
- worked 18
> states this weekend including the west coast on 40CW loading my 
rain gutter
> through an SGC tuner!
>
> Rick
> AI1V
> K3 728