[Elecraft] K3 with Mixw on PSK31

[Richard Ferch]

W?LV wrote:

> Recently I have been using my K3 and MixW.  During TX I notice that my TX
> freq will jump up (my guess) abt 10hz.  the receiving station then TXes at
> that new Freq when I go to RX.  I miss part re-adjusting to the new freq.
> 
> I have the TX locked on MixW and the sampleing rate is 12000 on the audio. 
> I am using the navigator interface and have had no problems until now and
> Firmware upgrades to latest beta.  I have not re-installed an earlier
> firmward version.  
> 
> I the TX shifts up the 10hz+- at infrequent times and when I go back to TX
> it goes to the original TX freq.  At some point on most TX's it will go up
> again and return again...
> 
> Any suggestions???

Most likely your sound card's record and playback time bases are not 
quite equal - this appears to be a common problem with sound card device 
drivers. MixW, like most sound card digital mode software, has a 
configuration option that lets you correct for this difference. It's 
called the "Clock adjustment" in the Sound device settings dialog. There 
are two separate clock adjustments, for TX and RX, and by adjusting them 
separately you can bring the two clocks into sync with each other to 
remove the TX/RX offset.

When you installed MixW, it should also have installed a "Sound card 
sample rate checker" program (CheckSR.exe) in your MixW program folder. 
If you start this program up and let it run for long enough to let the 
readings settle down (maybe an hour or so?), it will tell you what the 
two Clock adjustment parameters should be for the chosen sound card and 
sample rate. My guess is that they will turn out to be slightly 
different, and that this difference in clock rates has caused your 
transmit and receive audio frequencies to be slightly different, which 
is why you observe a shift between RX and TX. CheckSR tells you what 
adjustment figures (in ppm) to enter into both the TX and RX boxes, and 
   with a bit of luck after you do this you won't see the frequency 
shift any more.

For non-MixW users, try using Google to find CheckSR.exe.

73,
Rich VE3KI