As someone already pointed out, the PL tones are weird frequencies so they're not harmonically related. DTMF tones are similarly set at odd frequencies. DPL/DCS codes use only about 100 of the 512 possible codes for the same reason, so repeating bit patterns aren't falsely decoded. Paging tones are also similarly unrelated.
And of course you want to avoid 50 and 60 Hz, and some common harmonics of those. Bob M. ====== --- DCFluX <[EMAIL PROTECTED]> wrote: > Here is an age old question that has yet to be > answered satisfactorly. > > What are the CTCSS frequencies derived from? Meaning > why are they what > they are? Like 123.0, 127.3, Why not 120, 125, 130 > ETC? > > On 4/24/06, Dick <[EMAIL PROTECTED]> wrote: > > Ultimately, all the tonme signaling formats were > published in the old > > ITT Handbook for Radio Engineers. > > > > Dick __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
