Crystal control for 137 KHz
Tue, 17 Feb 1998 18:00:18 -0500
Paul Keinanen wrote:
> At 09:34 17.2.1998 +0100, you wrote:
> >>From HB9ASB, JN36PT
> >Frequency stability on 136:
> >Except for special modes, there is no necessity to have crystal
> >controlled oscillators on 136KHz.
> By the way, did you notice that the band frequency is 1/200 of the CB band
> frequency. If AM CB is currently used or has been previously used in your
> country, there are usually a lot of inexpensive surplus crystals available
> for the output frequencies of some CB channels. Dividing some of these
> channel frequencies by 200 (e.g. a flip-flop and two decade counters) will
> produce frequencies in the 135.7 - 137.8 kHz range.
> If the full set of crystals is available (or a CB synthhesiser is used) and
> since the original channel spacing is 10 kHz, the divider will produce spot
> frequencies at 50 Hz spacing.
> Paul OH3LWR