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[aprssig] Solar Powered Digi's and Voice Alert.

Robert Bruninga bruninga at usna.edu
Wed Dec 5 13:18:42 UTC 2007


>> One way to greatly facilitate TEAM operation on 
>> APRS is to put up a cross band transceiver for 
>> area-wide VOICE alert.  The input is on UHF 
>> (with PL) and the output is on the APRS channel
>> with PL-100.

> ...  Do you envisage it being used like a wide area 
> pager or something like that?

Hey, that is a pretty good analogy.  In fact, here is another
idea to greatly improve APRS performance in a SPECIFIC
geographical area, such as to support your local ARES/RACES
county communications:
1) Install the above cross band repeater for voice alert
2) Add a DIGI at the same location on 144.99 (if avail)

When a local net is activated, the call goes out on Voice alert
asking everyone to QSY to the local APRS packet channel.  And
the voice alert cross band can also output on that channel.
Here are benefits:

1) The local channel does not have the QRM from out of area, so
the channel load drops to only 5% of what it normally is.  This
improves APRS reliability by a factor of 20 or more, even low
power trackers can 
Be operating there without being clobbered.

2) With the 95% additional free-air time, the brief voice-alerts
will have a much much less chance of colliding with anyone.

3) Mobile D700 users now get full voice alert info, full local
APRS coverage, and their BAND-B is still available for their
other needs.

Something like that.

Bob, WB4APR
>> This way, voice alert is extended far beyond 
>> simplex to actually cover your entire local 
>> area.  This way, all APRS stations can
>> instantly make a voice alert to ALL stations 
>> in the area, no matter what they are doing 
>> with their other radios.
>>
>> Of course, this is pandora's box.  Over use, 
>> by one or more individuals could drive everyone 
>> nuts and cause them to turn off voice alert.  
>> But in my mind, it is a GREAT backup emergency
>> alert system.  If rarely used...
>>
>> Think of it as an APRS 911 system.  
>> IE, never used, but available for when you 
>> really need it.





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