[Elecraft] 4mhz osc and Firmware change.

[Ron Willcocks]

Hi all,
          This might be old hat, but I changed my MCU and IOC to cater for 
the KAT100 and I noticed my frequency was 150hz off freq after the change, 
which I presume was due to slight differences in the MCU chip....A slight 
tweak has put it back to within 20hz or so after warm-up and the overall 
change really wasn't worth worrying about, but I wonder if anyone else has 
noticed a change in the 4mhz osc  after a Firmware change?
In case you ask...yes I did do a CAL PLL after I made the change.
Not having decent frequency measuring gear I use WWV and Spectrogram to set 
my frequency, and perhaps someone can tell me if I am not correct in my 
assumptions here.
I set the pointer in Spectrogram to 800hz and tune the radio into WWV  so 
the received 800hz tone (in CW mode) from WWV is aligned with the 800hz 
pointer. I observe the reading I have and if it is low, I adjust C22  a 
smidgeon. I then do a CAL PLL and take another reading.
OK hit and miss, but it must be somewhere near it when I get within a few 
HZ .... It can take a few adjustments, and a bit of patience waiting for 
the CAL PLL to finish.
Anyway......I guess I will hear if my method is not correct!   I think it 
should be OK, as when I have WWV tuned in to what I make zero beat at 800hz 
on CW, then there is no difference in the audio between LSB and USB  when 
the announcer is on.
But of course there is another variable here......it will depend on whether 
you have your BFO for  USB and LSB aligned on your filters the same.  I do, 
and have checked by printing out the USB and LSB plots of Spectrogram and 
printed them so they are overlaid.
I would appreciate it if anyone can shoot holes in my reasoning here......
Cheers......Ron ZL1TW


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