On Thu, May 22, 2025 at 02:33 AM, KEN G4APB wrote:
I am a bit sceptical about ¡®cures¡¯ that cause problems to go away (or change characteristics), after resoldering. Surely a joint is either good or not connected.???
Not correct: a solder joint may be 'ok' for DC but poor for RF (or vice-versa).? Reflowing a solder joint, especially for the toroid wires that had enamel on them, can burn off the enamel around the full circumference of the wire, which will give a better RF connection, and improve RF performance.? This is partly due to the 'skin effect' of RF currents, which travel primarily on the surface 'skin' of the wire - and if all that 'skin' is not available, the current cannot travel as well through the connection.? It may connect and give 'ok' performance, but may also have limitations in performance depending on the circuit and use.
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And for what its worth, yes I also see the vertical lines on several 500Hz boundaries (when monitoring 50.313 on wsjt-x), which are most prominent on 6m - on both of my QMX+ builds, a rev2 and a rev3.? But these are really not a concern for me, since a) only the one at 1500Hz is strong enough to be annoying, b) FT8 and other signals still decode fine, even on top of those 'birdies', and c) I can easily tune my audio listening away from 1500Hz while doing FT8.
