Re: Realigning and Spectrum
|
Very nice. This looks like an easy way to put the VFO in the U.S. SSB band.
I'll bet the 18 KHz is from a CFL or LED light bulb.
My board came without C95 installed. The schematic shows 47 pF, but I am sure this is adjusted by the makers to achieve the proper VFO according to their criteria. I should think that starting with a 33 pF cap would be good to begin with for U.S. rigs. That should give a coverage of about 7.120 to 7.270 MHz. Mind you, the VFO still will drift a lot...
john AD5YE
On Saturday, December 10, 2016 1:13 AM, "John Sutter jds@... [BITX20]" wrote:
?
There must be a 18KHz source around my desk somewhere that's
coupling insomehow.?? False alarm on that one (probably).
As for alignment, I adjusted C93 but was only able to reach 7.257
MHz.
I tried different values for C95:
??? 100 pF 7.095 MHz
??????? 0 pF 7.033 MHz
????? 10 pF 7.139 MHz
????? 25 pF 7.257 MHz (original part)
????? 35 pF 7.35*? MHz (10 pF piggy backed on original part)
????????????????????????? ? * Estimated max frequency, forgot to
write it down
Now I'm covering 7.12 -> 7.3 MHz.
|
