At 8/28/2007 15:37, you wrote:
>The Network RC Parts are most often the biggest sinner. Cheap caps
>and resistors keep the show moving along even if you don't want to
>travel that road.
>
>cheers Bob,
>s.
Way back when I used tantalum capacitors, which I was told were the most
stable; the Rs didn't seem to matter so long as they weren't the dark brown
cylindrical ones (I suspect they're unsealed, as we have a bunch at work
that have changed by one whole standard resistance value just by sitting in
the bins for 30+ years). Since then I've discovered polystyrene & silver
mica. Only problem is the required C values for subaudible tones are a bit
above the max. values for those caps.
>ps: when we get done talking about the 555 ctcss encoder I've got
>a less popular 567 ctcss encoder/decoder circuit available.
Never used a 567 for encoding, but one of my first repeater controllers
used them for decoding "column 0" tones ("147*" column tone shifted
down). That worked until someone recorded us on the input & played the
tones back :(
No, my favorite was the SSI-202. Not too expensive & trouble-free decoding.
Bob NO6B
