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SW-40+ problem

Discussion in 'Homebrew and Kit Projects' started by KB1CKT, Aug 31, 2021.

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  1. KB1CKT

    KB1CKT Ham Member QRZ Page

    Hmm. Much poking around, thought I had it at one point, RF feedback on the PS. Nope. Only thing that changes the issue is touching the tab of the 2SC2078 final. The scope barely notices a change but on my FT-817 the harsh tone goes clean. Bad 2SC2078?
  2. KB1CKT

    KB1CKT Ham Member QRZ Page

    Apparently I'm all washed up--it sounds bad on my other receiver, but just has a Q and was given a 559 (NH to IL). Not bad. Maybe I'm hearing things, or it's real but of no consequence. o_O

    Edit: boy does this have a hot receiver. I keep the RF gain down but loud signals are LOUD. I keep the headphones well off my ears. Might have to add some series R or cut gain elsewhere.
    Last edited: Sep 6, 2021
  3. W1VT

    W1VT Ham Member QRZ Page

    There are ways to locally modulate a signal so it sounds bad on a nearby receiver. A common fix involves bypassing power supply rectifier diodes.
  4. KB1CKT

    KB1CKT Ham Member QRZ Page

    True. I have enough junk in my office, who knows what it might be. Would not think it the PS though, it's an Astron RS-20M, but maybe that. Or just any of a number of things in the office.

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