As I was aligning my "23/24 Re-cycle" 17 meter SSB rig, I noticed the tell-tale sounds of RF getting into my audio. (I guess I should be pleased -- my amplifiers are now producing enough RF to cause some trouble!) So this morning I went in and battened down the hatches in the AF part of the rig. Lead lengths were reduced. Unshielded cables were replaced with RG-174 (with due attention to "Murphy's Whiskers"). A ferrite bead was placed on the wire that carries voltage to the op-amp chip. I wrapped some foil (actually some of that conductive tape used to protect windows in alarm systems) around the plug on the D-104). And finally I cut out two pieces of PC board and made a shield for the whole AF section (see above). I think all this has had the desired effect. The audio sounds clean. I have the day off today, so if there are no Coronal Mass Ejections I hope to make some contacts on 17. Stay tuned!
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Re: restoring Millen GDO
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I would keep AC on the filament and use series resistance to reduce the
voltage as needed. Filaments generally last longer on AC, running on DC
they will ...
2 hours ago
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