HW101 oscillation/carrier supression

[Mark Graalman WB8JKR]

  Check and see if the balanced modulator is indeed
balanced, maybe its just out of adjustment, or maybe
you have a (some) bad diodes.

Mark  WB8JKR


On Sat, 21 Jul 2001 16:23:02 -0400 John Wb5Oau <johnmb at MINDSPRING.COM>
writes:
> I'm working on a recent acquisition that "worked perfectly" (and
> might
> have, if CW is all one used).
>
> The issue is, on 20m (have not checked other bands) if I set the
> driver preselector such that it peaks the output (and the receive
> sensitivity) there's about a 10W carrier that is present when
> keying the mic in either sideband. Tuning slightly off frequency
> (w/driver preselector) makes it go away...but then it  takes
> the drive away too!
>
> I vaguely remember such a problem with my original 101 (that this
> is to replace).
>
> Any hints? I know that the two variable caps that the Driver/Presel
> tunes are "in synch".
>
> Where to go first to fix such a thing? I have not tried it on
> other bands to see if this is an issue. I just fixed the dirty bias
> pot that prevented proper setting of the bias. There's lots of
> signal
> (nearly 100w out on 20m) so the rig is working well. Modulation
> looks
> fine too, if I could just get rid of the oscillation/unwanted
> carrier.
>
> Any and all help gratefully appreciated.
>
> Rgds
> John wb5oau/4

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