Richard Hoskin (VK3JFK) vk3jfk at amsat.org
Sun Jul 25 18:08:58 EST 2004

Hi All,

I would like to introduce APRS VOICE-ALERT into the VK APRS network. I
believe it would be useful and great fun.

VOICE ALERT: This simply means that you do not turn the audio down on
144.9/145.175, but instead leave it at high volume and then simply set
CTCSS tone 123 to mute the speaker. This way, you dont hear any packets,
but ANYONE can call you with VOICE on 144.9/145.175 to alert you by using
PL 123. You will rarely use this, and only use it to tell someone to QSY
to another voice channel, or read their status text on your Kenwood Radio
and QSY to the repeater they advertise they listen too, but it is one way
of assuring that ANYONE running APRS in simplex range of you can be
contacted with a voice call...

You won’t hear any packets except maybe one or two when another VOICE-
ALERT mobile is in range (about 8Km or so). But even then, he is only
beaconing once every 2 minutes (This is the recommended rate for VK3) and
so it is not bothersome at all.. In fact, it is nice to hear when someone
is nearby!

Note: This is NOT for QSO on 144.39.  Only as a calling means. then QSY...

A tone of 123hz has been chosen as this is the standard tone used in a lot
of VK repeaters and most people with home made tone boards will have this
tone set in their radio.

Here is Bob Brunnings description of Voice Alert.



Voice Alert", Most APRS mobiles are not aware of this very powerful

Having a 144.39 radio in a vehicle with the audio turned down or the
speaker disconnected is a waste of a perfectly good radio, ESPECIALLY
since everyone KNOWS you have a radio tuned to 144.39!  Thus, anytime,
anywhere, anyone can key up on 144.39 and call you by voice and know that
you will hear it.... if.....

Of course, no one wants to listen to packets, so, instead of turning down
your volume or disconnecting the speaker, just set CTCSS to "100"...
Bingo, no packets.  The only thing you will ever hear will be someone
calling you on voice with a PL of 100... (and of course, the occassional
packet of anyone else within range that is also running Voice Alert.)
But this is not bad. In my county, there are about 5 of us running Voice
alert.  But 99% of the time we are not in simplex range and so we never
hear any PL100 packets.  But when we do, then we ALSO know that one of us
IS nearby and on the air, and so we usually strike up a QSO on the local

The one place that I thought that Voice Alert would be a real nuisance
and cause me to turn my volume down too was at Dayton.  I expected to hear
dozens and dozens of other PL100 packets...  but I only heard TWO!..  Out
of the 50 to 100 APRS mobiles in Dayton, I remember only hearing 3 or four
packets in the morning when I drove into the HAMVENTION and only a few
more in the afterhnoon driving away...

So, only hearing one or two packets every few mnuntes I did not find to be
a problem at all.  In fact, when I pulled over to the side of the road
with an overheated engine, someone saw me (not even running APRS) and he
dialed in PL100 on 144.39 and asked if I needed help.  No way would he
have ever found me on the oddball repeater I was tuned to at the time.

THere is another GREAT advantage of running voice alert on the Handheld D7
too.  that is that by setting CTCSS 100 on 144.39, you dont have to mess
with the BALANCE setting.  How many times have you totally missed voice
operations because you forgot that your balance was set to ZERO for band
A?  Avoid the problem by setting CTCSS 100 and leaving the volume set to

Of course, only the Kenwoods can do Voice Alert easily because their TNC's
are internal and they hear all packets BEFORE the CTCSS squelch, but other
mobiles can do it too, if the owner is willing to tap his TNC off of the
discriminator before the normal audio squelch circuit...

Anyway, even if you cannnot use it in your situation, EVERY APRS person
should be aware of VOICE ALERT (CTCSS of 100 on 144.39).

And finally, this is NOT for QSO on 144.39.  Only as a calling means....
then QSY...

de WB4APR, Bob




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