[aprssig] 220 MHz transceivers
Scott Miller scott at opentrac.orgSun Nov 16 23:37:23 UTC 2008
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And if you're still confused, see this: http://www.youtube.com/watch?v=AMeaX8Kz2TM (Sorry, couldn't resist...) Scott N1VG Stephen H. Smith wrote: > Chris Rose wrote: >> 85MHZ is fm commercial broadcast range. Anything local to you there? >> >> >> > > The bottom of the FM broadcast band is 88 MHz with a (very) few minor > stations on 87.9. > > 85 MHz is the center of NTSC (North America) TV channel 6 which extends > from 82 to 88 MHz. I through of this, but neither the visual or sound > carriers of this channel land on the frequency originally mentioned. > > > > Speaking of TV channels, I am predicting a MAJOR renaissance of > six-meter activity next year. > > Channel 2 (54-60 MHz) has rendered 6M operation almost impossible in > many major cities of North America. Even when the lower visual > sideband of channel 2 is suppressed 60-70 dB (from a quarter-megawatt or > more), the net result is to blanket most of the 6-meter band with > S9-plus sync hash and noise. Not to mention the potential for > interference to TVs from 6M transmitters (TV tuners with lousy adjacent > channel rejection). This will change radically 17 February 2009. > > > > The chaotic transition to all-digital TV broadcasting in the US has > stations currently simulcasting on analog and digital channels. Nearly > all digital transmission is currently in the UHF band. After the analog > shutdown next Feb 17, about half of the VHF HIGH-band TV stations (chans > 7 through 13) will move their digital operation to the classic VHF > channel occupied currently by their analog operations. The other half > will just shut down the analog operation and continue the digital > operation on UHF only, although there is going to be a lot of jumping > around from one UHF channel to another. > > To add to the confusion, the (UHF) digital channels identify with the > VHF channel numbers of their legacy analog counterpart stations no > matter what channel they are actually on. [The digital transmission > protocols allow you to send any arbitrary channel number as part of the > transmission.] For example, here in Los Angeles, the station that shows > up on my digital TV as "Channel 7.1 KABC-DT" is actually on UHF channel > 57, but will move to the "real" channel 7 when the analog side shuts > down. > > > However, virtually ALL analog LOW-band TV stations (chans 2 through 6) > will just shut down the analog operations, and continue their current > digital operations on UHF only. A new generation of "all-channel" TV > antennas from Channel Master and Winegard are now on the market. They > are about half as large as their traditional versions, because they no > longer cover the low-VHF band. > > The bottom line is that channel 2 is going away COMPLETELY!!! Not > just going digital but going silent which will make the 6 meter band > instantly far more usable than it is now. > > Lots of info on the DTV channel changes and re-assignments at this website: > > <http://rabbitears.info> > > > > > > -- > > Stephen H. Smith wa8lmf (at) aol.com > EchoLink Node: 14400 [Think bottom of the 2M band] > Home Page: http://wa8lmf.com --OR-- http://wa8lmf.net > > World Digipeater Map > http://wa8lmf.net/APRSmaps > > JavAPRS Filter Port 14580 Guide > http://wa8lmf.net/aprs/JAVaprsFilters.htm > > "APRS 101" Explanation of APRS Path Selection & Digipeating > http://wa8lmf.net/DigiPaths > > Updated "Rev H" APRS http://wa8lmf.net/aprs > Symbols Set for UI-View, > UIpoint and APRSplus: > > > > > > > > > _______________________________________________ > aprssig mailing list > aprssig at tapr.org > https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig > >
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