On Fri, 21 Aug 2009, John Sehring wrote: > Then of course 12 identical receivers, I'd use, oh, Mitrek's or > MaxTrac's. I think I'd not be inclined to use Micor or any of the > Syntor radios because they are purpose-designed radios for quite wide > freq. spreads. This necessarily makes for the compromise of a wider > RF & mixer front end. I think I'd like maximum RF selectivity on both > 10m and 6m (the latter esp. where TV ch. 2 is used on the air.
The Syntor (not Syntor X or Syntor X9000) has the selectivity of a Mitrek, with a synthesized and programmable receiver. The "spread" on the front end of the Mitrek, Micor, and Syntor is 2MHz. The Syntor X, X9000, Spectra, Maxtrac, etc. is 22-24MHz. And at this point, if you show interest in Mitreks, you can probably receive a lifetime supply for shipping. > Next would come the rx voting scheme. It'd have to be carefully designed > (the squelch ct's, too, probably no Micor-style circuit here). Maybe a > combination of quieting and signal strength would be used for rx selection > or combining (see my earlier note). Motorola once (abt. 1960) had a squelch > ct. which fed a bit of audio into the noise amp to inhibit squelch clamping > on modulation. It also used a bit of both 1st & 2nd limiter levels in the > mix. I don't know that it ever was commercialized. Digital backhaul means that you don't have to equalize the radio link. And you're going to have four receivers from each site, so you'll want to find some way to multiplex them. -- Kris Kirby, KE4AHR Disinformation Analyst
