[aprssig] 220 MHz transceivers
Scott Miller
scott at opentrac.org
Sun Nov 16 18:37:23 EST 2008
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:
>
>
>
>
>
>
>
>
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