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[aprssig] Regional Voice Alert VHF/UHF Plan B.

Robert Bruninga bruninga at usna.edu
Wed Dec 5 16:59:58 UTC 2007


Still pondering... another idea for the ultimate local dedicated
APRS support system using a pair of VHF and UHF transceivers and
KPC-3+ TNC is to configure them for this arrangement:

1) VHF and TNC Acts as 144.99 ==> 144.39 digi
2) UHF input gives regional Voice Alert out on 144.39
3) Mobile VAlert from 144.99 goes to UHF voice output

Here is what you get:

Netcon or anyone can call everyone in the region on Voice Alert
via the UHF input.  Mobiles can QSY their A-Band and APRS to the
144.99 input (keeping 144.39 output so they still see
everything).  But being on the 144.99 local input, their packets
have 95% less QRM and are much more reliable and when they are
digipeated onto 144.39, they get local priority.

While their mobile TX is on 144.99 (where the channel is now 95%
clear), any of their Voice Alert transmissions on their radio A
side will not QRM anyone on 144.39, but their voice will be
relayed on the UHF output.

So these APRS operators now have full PRIORITY local APRS
digital communications AND local wide area APRS VOICE (back
channel) communications on the A side of their radio and their B
side can still be used for their other needs.

Oops.. I guess they need to listen to the UHF channel to hear
the other non-simplex APRS voice Alert comms from the cross band
repeat.  So this kinda takes away from the freedom of band B.

Hummh..  Need a plan C.  Next message...

Bob, WB4APR


> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org 
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Robert
Bruninga
> Sent: Wednesday, December 05, 2007 8:19 AM
> To: 'TAPR APRS Mailing List'
> Subject: RE: [aprssig] Solar Powered Digi's and Voice Alert.
> 
> >> 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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