I forgot mention I use a bourns 100K, it is preferable over a 10K. More steps due to smaller wire gauge in the wire wound
pots!
--------
I am very pleased with myself!! got the drift down to +-20Hz, even blowing on the board changes it by 50Hz momentarily.
Changed C91-96 with C0G/NP0 SMD's and it was almost perfect! Choose 5% types.
I changed the trimmer C93 with a murata Green.
then:
Old rule of the thumb I followed..
Low inductance higher capacitance makes a stabler VFO!
I reduced the original 9.5uH yellow coil to about 6uH.
Added 120pF across C95
Then I paralleled 2-3 MV209's across D9. You can parallel them to suit your tuning range. 200 or 300 Khz!
You need a frequency counter for this mod.
73
--
Raj, VU2ZAP
Bangalore, India.
Raj vu2zap