[Elecraft] Re: K2 birdie at 28.265 MHz

[wayne burdick]

The (-) voltage generator (oscillator) in both the KIO2 or KPA100 
generates a couple of weak birdies. They will move around a bit from K2 
to K2, because the birdies are the result of high harmonics of this 
crystal oscillator mixing with high harmonics of the K2's VCO, and the 
fundamental crystal frequency has a tolerance of about +/- 0.5 kHz.

We attempted to position the birdies in obscure parts of the spectrum. 
If the 10-meter birdie happens to hit close to a beacon that you want 
to monitor (28.265 is in the beacon area of the band), you should be 
able to move it a bit by changing one capacitor in the crystal 
oscillator. In the KIO2 case, the best choice would be C14. It is 
normally 56 pF, but paralleling another 10 pF across it should shift 
the oscillator a kHz or two, enough to move the signal off a CW beacon. 
The value of C14 isn't critical; it could change +/- 20% without 
significantly affecting output of the oscillator.

73,
Wayne
N6KR

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