K3: Loss of rx signal

[Rick Miller - N1RM]

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

[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


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