[aprssig] Voice Alert ALL-CALL

[Robert Bruninga]

We are putting up an Experimental cross-band all-call Voice
Alert system in Central Maryland.  It will extent the range of
Voice Alert calling from the 3-5 mile simplex to 50 miles or
more to cover the entire area.

It is on a high hill, with 445.925 CTCSS 100 input.
With 144.39 PL 100 output.

It will serve as an all-call capability for APRS operators in
the area.  TO make an all-call announcement, one just transmits
on 445.925 with PL 100 and the voice call goes out from that
location to all mobiles in 50 miles on Voice Alert 144.39 PL
100.  The voice call must ALWAYS announce something like "via
UHF Voice Alert" so that those that hear it will know that they
cannot talk back using normal 144.39 voice alert.

This should be useful as a backup emergency all-call capability.
We'll let you know how it works.  It is NOT for packets, only
special brief voice calls for contact.  There is notthing worse
than PL 100 packets when no one is listening!

Bob, WB4APR