Order Tray | Contact Us | Home | SIG Lists

[aprssig] 220 MHz transceivers

Scott Miller scott at opentrac.org
Sun Nov 16 23:37:23 UTC 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:
> 
> 
> 
> 
> 
> 
> 
> 
> _______________________________________________
> aprssig mailing list
> aprssig at tapr.org
> https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig
> 
> 




More information about the aprssig mailing list