But my point was that although temperature stabilization might not be the current 'trend', it's still a perfectly acceptable alternative to compensation.
Yes, synthesizers have advantages. Joe M. Ron Wright wrote: > > Joe, > > As you know crystals are not bad. And when one puts on a repeater that > stays sometimes for couple decades on the same freq crystals are fine. > > Also as you know crystals take time to get. Having synth repeaters/rigs > allows even the commerial guy to keep a few radios for spares allowing to > quickly program up for a customer in the event of a failure. This is where I > see synth has a deffinite advantage. Out of the box, 10 minutes later ready > for service. > > As for repeaters synths did have the problem of more noise, but engineering > solved this in repeaters. Another reason why not to use 2 mobiles or HTs for > a repeater. There are other reasons. > > 73, ron, n9ee/r > > >From: MCH <[EMAIL PROTECTED]> > >Date: 2007/07/12 Thu PM 12:26:42 CDT > >To: [email protected] > >Subject: Re: [Repeater-Builder] Re: crystal/channel element compensation.. > > > > >Regardless of how many modern radios use temperature stabilization, that > >does nothing to diminish its effectiveness at keeping the frequency > >stable and eliminating the need for temperature compensation. > > > >Few rigs today use crystals for the operating frequency. Does that mean > >crystals are bad? > > > >Joe M. > > > >Bob M. wrote: > >> > >> I beg to differ. > >> > >> Few MODERN commercial rigs (built since the 1980s) use > >> heaters, but prior to the Micor, almost all of the > >> vacuum-tube two-way radio sets definitely used crystal > >> heaters. I have the burn marks on my fingers to prove > >> it. The temp was usually around 85C and the units > >> operated from 6 or 12 volts which was always available > >> as a filament voltage. The GE units could hold two > >> crystals and used an 8-pin octal-style plug-in module. > >> The Motorola units could hold one crystal and used a > >> 4-pin rectangular module. When ordering crystals from > >> ICM, one could specify whether the unit was to be > >> heated or not, and if it required large pins (to plug > >> directly into the radio's socket) or small pins (to > >> plug into the socket inside the heater). I'm not sure > >> you could call these "ovens" as they used a mechanical > >> thermal switch to control the temperature and the > >> crystals were firmly mounted inside the units. > >> > >> Crystal ovens were very common in older (tube-era) > >> broadcasting equipment, however in the more modern > >> synthesized units they might have a TXCO or even an > >> OXCO for a reference oscillator (depending on how > >> cheap the manufacturer was). AM broadcast stations > >> rarely use ovens these days; the crystals are stable > >> enough to keep the carrier within +/- 10 Hz (about 10 > >> ppm) which is better than the FCC requirement. > >> > >> Bob M. > >> ====== > >> --- Ron Wright <[EMAIL PROTECTED]> wrote: > >> > >> > Few commerical rigs use a heater to stablize the > >> > frequency. Some see it in applications such as > >> > broadcasting where very tight, much tighter than > >> > commerical, frequency is required. > >> > ... > >> > >> > >> __________________________________________________________ > >> Be a better Globetrotter. Get better travel answers from someone who > >> knows. Yahoo! Answers - Check it out. > >> http://answers.yahoo.com/dir/?link=list&sid=396545469 > >> > >> > >> Yahoo! Groups Links > >> > >> > >> > > > > Ron Wright, N9EE > 727-376-6575 > MICRO COMPUTER CONCEPTS > Owner 146.64 repeater Tampa Bay, FL > No tone, all are welcome. > > > Yahoo! Groups Links > > >
