[Elecraft] (Elecraft) CAL PLL

[Don Wilhelm]

Kev,

Great about your K2 completion.
For doing CAL PLL again, check the accuracy of your K2's frequency. Do 
that on the highest frequency you can receive a known frequency signal - 
as long as that frequency is in the 17 meter band or lower.  If the 
frequency is within 20 Hz of the correct dial reading, don't bother.
OTOH, if the frequency is not correct, then yes, setting C22, followed 
by CAL PLL and then CAL FIL should correct it.  See the procedure for 
setting C22 on my website www.w3fpr.com.

If the known frequency signal is not an AM station, things get a little 
more complicated in determining the correct tuning of that station - 
send me a private email and I can help you with the correct tuning.

Bottom line -- if your frequency readout is not correct, then you will 
have to go through the full process of setting C22 followed by CAL PLL 
and CAL FIL within a short period of time.
The 4 MHz reference oscillator is only controlled by the 4 MHz crystal 
and can drift over time.  The exact frequency of that oscillator is not 
critical for normal operation, it is only a clock for the MCU.  However, 
before running CAL PLL and CAL FIL, it should be set accurately if you 
are to achieve correct dial frequency readout -- so do the entire 
process in "one sitting" so the 4 MHz oscillator does not drift 
substantially during the process of setting C22, running CAL PLL and CAL 
FIL.

73,
Don W3FPR

On 2/5/2015 10:51 PM, Kevin Schache wrote:
> WOW!!!
> This building project has been fantastic. I've certainly learned or 
> relearned heaps...
> Thanks to Elecraft and all those who have helped me along the way, I 
> am extremely happy with results.
> Everything is now complete and all seems to be working well but I 
> can't recall if I did CAL PLL after resetting c22 in my final alignment.
>
> If I repeat CAL PLL on my K2, does that mean that I must redo CAL FIL 
> and all filter alignments again?
>
> I did filter alignments using a noise generator and Spectrogram and 
> the graphs appear much as the examples in Don's W3FPR alignment 
> instructions, but I'm not too sure exactly what I am looking for In 
> Spectrogram. I simply tried to get graphs to be as similiar as 
> possible to the examples. Apologies for dumb question but, Is there 
> something special I should be looking for? Something to be minimised 
> or maximised in the graphs?
>
> If I do CAL PLL and CAL FIL again, does that mean I should also redo 
> KAT100 settings?
>
> I've also built the cable between k2 K102 and PC and all tests ok.
>
> I've not made any on air contacts yet with this rig other than into a 
> dummy load and some testing of my  antenna with KAT100.
> I wanted to get alignments done as well as possible first.
> Maybe I'll get my feet wet this weekend!!! :-)
>