Jukka,
Congratulations. With those voltages, you could go even a bit higher
in capacity, but it is OK as it is.
Size only matters to the extent of physical fit. If you were able to
get the larger caps mounted and the K2 panels still fit, all is well.
73,
Don W3FPR
Jukka Tarvainen wrote:
Hi Don!
Thank you for good advice once again!
C75 in your K2 needs less capacitance. You can try several other 470 pf
capacitors (NPO disc ceramics or C0G mono capacitors) to see if you can
discover one that is on the low side of tolerance rather than the high
side (like yours), or you can replace C75 with a 390 to 450 pf capacitor
and add padder capacitors to bring the total capacitance up so the 160
meter VCO voltages are in the 1.5 to 7.0 volt range over the entire
tuning range.
Today I got some NPO disc ceramic caps and tried different variations. With
330+150 pF in parallel measured VCO voltages are now inside 1.5-7.0 V:
1800 kHz 1.6 V
2000 kHz 4.0 V
These new capacitors are not small in physical size, bigger is 10 mm, about
0.4" in diameter. Does size matter in this circuit?
Best Regards
Jukka, OH4MFA
K2/100 #4293
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