On Mon, 2008-06-30 at 20:13 -0500, Stuart Rohre wrote:
> It might be RF getting back into the audio circuits, one thing to try is
> open up the radio and loosens and retighten all screws that ground shields
> and braids to board ground planes or case.
>
> Also, 555 is an older radio now, and electrolytic capacitors might be
> subject to needing replacement.
> Check for large values in audio stages.
>
> Does the radio do this with a dummy load in place of antenna? In that case
> it might be a capacitor going bad.
>
> If it is OK on dummy load but not on dipole, try RF ground fixes, or move
> antenna further away from the radio. Likely it RF if only seen on the
> dipole.
>
> Stuart Rohre
> K5KVH
>
One other test for spurious outputs. Use the tuner on the dummy load.
The tuner bandwidth will be similar to the tuner bandwidth on a nearly
resonant antenna. If the tuner can't be tuned to a perfect match with
the Scout, then the Scout is putting out RF at two different
frequencies. That could come from bad circuit board grounds or a tuned
circuit problem on the band plug in, possibly only mixer balance or
alignment.
73, Jerry, K0CQ
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|