[aprssig] 220 MHz transceivers
Chris Rose kb8uih at sbcglobal.netMon Nov 17 01:13:16 UTC 2008
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OK, I'm not that far gone yet. :) Chris KB8UIH --- On Sun, 11/16/08, Scott Miller <scott at opentrac.org> wrote: > From: Scott Miller <scott at opentrac.org> > Subject: Re: [aprssig] 220 MHz transceivers > To: "TAPR APRS Mailing List" <aprssig at tapr.org> > Date: Sunday, November 16, 2008, 6:37 PM > 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 > > > > > > > _______________________________________________ > aprssig mailing list > aprssig at tapr.org > https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig
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