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

Wes Johnston, AI4PX wes at ai4px.com
Thu Dec 6 04:46:10 UTC 2007


I'm going to assume that the average person hooking this up will program the
radio to use PL tone decode squelch, and will hook everything to the speaker
jack on the back of the radio.  The problem is that the speaker audio will
remain muted until the pl tone decoder figures out there is a valid pl
tone.  once that happens, the kpc3 will take a few mS to figure out it's a
packet if it is hooked to the speaker jack of the radio.  The "parrot" box
will record just a snippet of the beginning of the packet and dutifully play
it back onto 144.39.

Now if you hook the kpc3 to the disc audio so it can hear the packet sync
tones before the pl decoder fires, it'll never allow the parrot box to hear
anything and you'll have a winner.... or if you can make sure that the
parrot box won't play back a voice recording less than 100mS long.

So i'd have to say the correct way to do this is to wire the kpc3 to the
mini-din datajack of a vhf radio and the voice recorder to the speaker jack.

Wes


On 12/5/07, Robert Bruninga <bruninga at usna.edu> wrote:
>
> OK, plan C (for the alternate APRS local channel to support
> priority local emergency and special event operations).
>
> This one is just a single VHF radio, and a KPC-3+TNC and a
> simplex voice recorder (About $10?).  Lets see if this works...
>
> 1) RX on 144.99, TX on 144.39 normal digi
> 2) Voice recorder records any PL100 VOICE on input
> 3) KPC3+ mute ckt ignores recording of PL100 packets
> 4) Voice recorder repeats only voice on 144.39
>
> This gives:
> A) Priority to local APRS data on 144.39
> B) QRM free higher reliability local APRS input
> C) Ability for VAlert to cover broad area
> D) All of this on Band-A of D700 or using only a single band
> APRS radio.
> E) D700 band B's can support all other comms.
> F) Lets local APRS operators shift 144.39 +600 in support of
> this emergency event or special event and have priority
> communicaitons which includes the occasional area-wide Voice
> Alert.  All on Band A of a D700 or D7 or on a single band VHF
> APRS radio.
>
> Bob, Wb4APR
>
>
>
> > -----Original Message-----
> > From: Robert Bruninga [mailto:bruninga at usna.edu]
> > Sent: Wednesday, December 05, 2007 12:00 PM
> > To: bruninga at usna.edu; 'TAPR APRS Mailing List'
> > Subject: Regional Voice Alert VHF/UHF Plan B.
> >
> > 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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> > > aprssig at lists.tapr.org
> > > https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
> > >
> >
> >
>
>
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-- 
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