Re: Emergency freq's?
- From: et472@xxxxxxxxxxxxxxxxxxx (Michael Black)
- Date: 9 Sep 2006 05:14:31 GMT
"Lisa Simpson" (none@xxxxxxxx) writes:
I just obtained an old Regency Model Z10 scanner at a moving sale (alaDoes it even program?
Cuhulin) for $2.00 which was owned by an old tinkerer which seems to work
perfectly. How does one find out what ones local emergency frequencies are
so I can program them into this old beast?
If it's old enough, the only way to change frequency is to buy new
crystals.
IN the beginning, there were "public service band" receivers, which
were tuneable. Often these were just a band on a portable radio, but
there were some dedicated home and mobile units. Often they weren't
that great, rather broad selectivity and of course the variable tuning
meant one couldn't switch between frequencies fast or easily, and they'd
not stay on frequency.
SOme of those had besides the variable tuning a socket so you could
plug in a crystal to get one crystal controlled channel.
As the sixties turned into the seventies, better receivers came along.
The drift was towards crystal controlled, and you'd need a crystal for
each frequency you wanted to receive. Since the frequencies in use
varied from location to location, you'd get the empty unit and then
have to spend more money on crystals.
What seems now as a brief time later, scanning was added. Electronic
circuitry that would take the place of the channel selector. It would
cycle through the channels until the squelch opened (indicating a
transmission on that frequency) and the cycling would stop. When the
transmission ended, there would be a delay (in case the other side
transmitted, or in case the transmitter came on again) of ten seconds
or so, and then the cycling would begin again. THis worked well,
since most of those frequencies saw limited use in any given time period,
so the scanning meant you could check the ten or whatever frequencies
almost continuously.
But ICs came along, allowing for practical synthesis, and likely people
didn't like the limited number of channels (or the six bucks or so
they needed to spend on each crystal). So the move was to receivers
that had synthesized tuning, in effect giving crystal control but
on each and every channel in the band. Accurate and stable tuning,
but every channel (like in the old days of variable tuning). And
hence the scanning got better, since one likely wouldn't want to
bother with scanning all frequencies (because they weren't all
being used).
Now, if the thing only has ten channels as one message suggested,
that suggests a crystal controlled scanner. The only way to
"program" those is to buy new crystals for the frequencies you
want to receive. You'll have to uncover the equation for
getting the right frequency, and then order crystals from a
crystal manufacturer. Likely now that will cost you a fair
amount to fill all the slots.
Michael
.
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- Emergency freq's?
- From: Lisa Simpson
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