[Elecraft] K2 #4472 new builder question on 4 mhz alighment

[Mike S]

At 05:30 PM 11/11/2004, jerry wrote...
>Anyway,   I am now using Spectrogram and I have the Yaesu set for Lower SB and receiving  the tone of WWW (10MHZ) at the 1k mark, the display on the MP reads  10001000 Hz.
>On the   K2,  using LSB , the display reads 9999.84  and the tone of WWW (10Mhz) at the 1k mark.

So far, so good.

>What do I adjust ? If i adjust C22 nothing changes.     All other adjustemts I had no probles.

Yes, you have to adjust C22, but nothing will change after you do until you run CAL PLL, then CAL FIL again. C22 affects the 4 MHz timing for the control processor, which handles the frequency counter function. When you do a CAL PLL and CAL FIL, the frequency counter is measuring VCO and BFO frequencies and storing the settings in a lookup table. From then on the table is used. Adjusting C22 without then running CAL PLL or CAL FIL doesn't do anything useful.

Following the instructions below will get you very close. This is from a year old post by Wayne. In my experience, you actually want the VCO set about 10 Hz lower than the BFO to the most accurate readings.

>Here's the procedure. It requires revision 2.XX firmware, and assumes you have already done Alignment and Test, Part II, at some point. The K2 should also be allowed to come up to room temperature.
>
>1.Tune in a signal at a known frequency. Use one that's at an *exact* kHz boundary, so you can easily see when the VCO and BFO readings match in step 2. (I use WWV at 10, 15, or 20 MHz.) Use USB or LSB mode rather than CW, so that there will be no CW receive offset. In the case of a K2 I was calibrating, the VFO read 10000.17 when the signal was tuned in perfectly. If it had read 10000.00, no further improvement would have been possible.
>
>TIP: Zero-beat the carrier precisely, or listen to a voice signal and adjust the VFO for the best quality. The more accurately you tune in the signal, the more accurately you'll be able to set C22, below.
>
>2. Run CAL FCTR. Now alternately move the K2's internal counter probe between TP1 (VCO) and TP2 (BFO), adjusting C22 in small increments until the kHz and Hz digits at the two test points match as closely as possible. In my case, the two readings matched at 14913.60 and 4913.60. The difference is exactly 10000.00--the frequency of the on-air signal.
>
>3. Put the counter probe on TP1 (VCO), switch to 40 meters, and run CAL PLL.
>
>4. Put the probe on TP2 (BFO) and run CAL FIL. For each operating mode, vary each filter (or BFO) setting up 1 count, then back down, to force the K2 to take a new BFO measurement for each and store it in EEPROM.
>
>The VFO dial should now be very well calibrated.