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Re: [aprssig] Holiday Traveling = 144.39 CTCSS 100

On Tue, 16 Dec 2003, Keith Allen asked about VOICE ALERT:

> Can I presume that when the ctcss 100 is engaged on both sides (xmit and
> rx) of the D-700 or D7 , that the only APRS traffic that will make it
> into my radio (TMD-700) are the ones from stations also using the 100
> ctcss tone?

No, ALL packet stations will still be heard by the TM-D700 APRS radio
because the internal TNC is connected before the CTCSS squelch.

> In other words local digipeaters and such that receive my signal will
> not be able to send back due to the 100 hx tone on my receive side.

No, APRS continues to work normally.  That is the beauty of VOICE ALERT.
It is like getting a 3rd free radio in the car.  Since you are on APRS,
everyone knows you are also monitoring 144.39 for VOICE ALERT with CTCSS
100, so no matter what you are doing on any other freq, they can still
always call you quickly with PL 100 on 144.39 and ask you what freq you
are on or ask you to QSY to their working voice channel...

> Bob Bruninga wrote:
> >Remember, during holiday travels, your BEST chance of hearing
> >a fellow traveler DIRECT, is monitoring 144.39 CTCSS 100.

> >144.39 CTCSS 100 works far better than listening to 146.52, because on 52,
> >someone has  to be calling CQ every 2 minutes so that there is any chance
> >of someone in range hearing them.  Most dont, thus many QSO's are lost.

> >Think of 144.39 as a RADAR ping.  The vast majority of APRS mobile
> >operators are pinging away once every minute or so with a PL 100 packet
> >position report.  This serves as an automatic "in-range" signal probe.
> >But, not only are they transmitting with PL 100, they also have their
> >speakers MUTED with CTCSS 100 so that they can then HEAR a voice call from
> >ANYONE that calls them using PL 100.

> >Thus, if you hear a PL 100 signal on 144.39, you know the following:

> >1) He is in SIMPLEX range
> >2) He is LISTENING with his speaker for a voice call.

> >In APRS lingo, we call this "VOICE ALERT" since we are all driving around
> >with one radio permanently on 144.39 anyway, we may as well use its
> >speaker and "pings" on those rare occassions when someone wants to get our
> >attention for voice by using PL 100.  But PLEASE CONSIDER:

> >1)  VOICE ALERT is only for CALLING or ALERTING the other station by
> >voice to QSY to your chosen voice frequency (usually 52)... Do not QSO

> >2)  When you call someone on 144.39 PL 100, you MUST say "voice Alert" or
> >he won't know you are on 144.39.  Voice Alert calls are rare, and without
> >giving him a clue, he will assume your voice came on his other band...

> >SO, Even if you never have used APRS, don't overlook this simple "radar
> >detector" for travelers in simplex range.  It works.  Maybe only a few
> >times a day on a long trip, but it works better than waiting for someone
> >within 5 miles of you to call CQ on 52...

> >de WB4APR, Bob

Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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