QCX-20 Rev3 Low Output (2.3W) and dissonance


Bill NF6R CA
 

Hello,

I've been reading threads here and Han's low power article, and I'm working through them.  Continuity good through LPF, resolder caps 25-30, power doesn't climb when the key is held (but it does drop 0.2 watt).  Took one wrap off L1 and L2, two wraps off L3.  Stretched windings on L1 and L3, squeezed on L2.  Using the internal power meter, I can get it up to about 2.3W without problems.  If I go any higher, I get a dissonance in the 700Hz tone about 0.5 second after key down and Q1-3 get hot fast.  I can order and changes caps 25 and 26, but the dissonance issue doesn't seem to come up.

Another question, I've seen Allison mention the L4/C30 tuned circuit at 14.030.  Is that one of the alignments or is that just in the design?

Thanks for your help,

--

Bill - NF6R
SKCC 20696 NAQCC 9984 FISTS 19479 CalQRP 78 Flying Pigs 4181

Join QRPLabs@groups.io to automatically receive all group messages.