The second mini-project of the year is almost complete.
Two things had to happen with the IC-910:
1) The original reference oscillator needed to be replaced with a high-stability oscillator. This was necessary, because temperature drift cannot keep the IC910 on frequency, especially when operating at high power levels.
I got the new oscillator mounted on the PLL board, and then the adjustment started. Initially I adjusted the output signal while transmitting low power FM on 70cm. Yes using lots of attenuation. I was using my microwave capable spectrum analyzer with a 10MHz GPSDO as reference. The trimmer in the oscillator was a bit fiddly to work with, but I got the initial 70cm frequency adjusted within 150Hz of the set frequency. After some warm up it looked a bit better.
Time to mount the shield for the PLL and the 23cm module. This is a rather easy add-on.
Set the main band to 23cm and test on 1296.000MHz. The frequency was less than 250Hz, and after warm-up it was within about 150Hz.
Now the radio is re-assembled with all the covers, and tomorrow I will make another test of frequencies with the radio fully assembled, and after a good warm-up period.
I do not expect any significant change, but I do need to check, so I know the offset.
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