I've had the antenna selection switch on the back get dirty. Cleaning it solved
my problem...back when I had a 509.
--
Joe Hutchens ( AJ8MH )
http://webpages.charter.net/aj8mh-radio/
---- Roscoe Primrose <roscoe@aiko.com> wrote:
> My Argonaut 509 seems to have a serious receiver sensitivity problem.
> The other night when 80M was fairly noisy, I was getting noise at S6-S8
> on an FT817, hooked the same antenna to the 509, an even with the RF
> gain all the way up, the S-meter baorly moved, if at all. RF noise is
> generally not enough to move the S-meter, and I've made several easily
> understandable QSOs with no motion of the S-meter. The S-meter is
> working, with very strong signals it does occasionally get up to S-9. I
> originally thought the problem was the first stage dual-gate MOSFET, but
> I'm pretty sure that's not the problem at this point. When
> troubleshooting the first stage MOSFET, when I hooked a DMM lead to gate
> 1 I get a stronger signal (not just noise, but signal as well) from the
> test lead than I do from the antenna connected to the unit. On the RF
> front-end board, the antenna signal goes through an input cap, a
> transformer/cap combination that's a 9MHz trap (VFO), through a tuned
> transformer which is part of the pre-selector, through a coupling cap,
> and to gate1 on the MOSFET. Connecting the DMM lead directly to gate1
> causes an increase in signal & noise, connecting it anywhere before the
> coupling cap results in no change in signal level. I changed the
> coupling cap, but there was no change in performance.
>
> Anyone familiar enough with the front-end on these rigs to have an idea
> as to what I can check next?
>
> Thanks, AJ4LL
>
> --
> "The tree of liberty must be refreshed from time to time with the blood of
> patriots and tyrants. It is it's natural manure."
> Thomas Jefferson, 1787.
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|