Hi Chuck, > "Chuck Kelsey" <wb2...@...> wrote: > Skipp, > I suspect that you were the exception rather than the > rule, then.
I'm often told the above... for more than one reason. Why some of you are smiling sideways when you say that is another subject unto itself. > To me there are better ways to do it than a 567. Sure there are... but back in the early 1980's I had a lot more time than pocket money so I built a lot more discrete circuits and the 567 was pretty inexpensive. > I remember playing with various 567 circuits back in the > 70's. Never could get reliable performance. I tried a number of different circuits using a lot of the different chip available at the time. I didn't have much of a problem with the 567 circuit once the support parts stopped changing value or I used better quality parts. > Used them for paging frequencies. Gave up and started > using commercial encoders and decoders and never looked > back. Of course when it became time to do things on a more professional level... I used more professional equipment. But I built most of my early ham repeater controllers from scratch. > Maybe you can give the guy some guidance to get some > stability and choke down the bandwidth so that adjacent > tones don't false the thing. > Chuck Rather than reinvent the wheel... I provided a real world CTCSS circuit references for those who would actually care to chase that information down. There are more practical methods to decode CTCSS... but the NE-567 or equivalent will do the job. As Jeff said, yes it is "old school" but at least it is possible to use the chip for the cause. cheers, s.
