On Sat, Jul 13, 2024 at 10:51 AM, John Z wrote:
With focus on the 20m LPF, I suggest checking the inductor leads first. A poor joint that is the result of inadequate enamel removal can wreak havoc.
Well, it was hard to confirm visually, and I was unable to recreate the fault on the bench, but this may have been the source of trouble. I removed the solder from the 20m hand-wound inductor leads, gently scraped at the enamel with an X-acto knife blade, and then resoldered each one. (I did one lead at a time this way, so the inductors would not fall off the board!)
A follow-up SOTA activation was successful on 20m, so crossing fingers that it's now fixed. Until I test it in colder weather I won't be sure however.
Leigh KG7WED