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[aprssig] V-Alert was D700 Tip. Reading Mail

Steve Noskowicz noskosteve at yahoo.com
Wed Aug 1 00:33:40 UTC 2007


  CAUTION.  I'd like to know if anyone actually
*measured* a radio to verify that "Split PL tones"
actually is done.  It is inconsistent with the
intended practice (Obviously not impossible, but not
practical for actual use - I won't detail why).

    I haven't checked all of my radios, but at least
one (TH-F6A) that I verified (with measurements)
because I wondered about this, only 'allows' you to
infer that you can *use* different T & R tones in "CT"
mode.
  Detail:
    When the radio is set for "T" in the display (Tx
tone only), you can set a frequency in the menu and
that tone freq is transmitted (as we would think).
    NOW...
    When the radio is set for "CT" in the display (Rx
or tone squelch), you can indeed set a *different*
frequency in the menu.   However, that tone freq is
*BOTH* transmitted AND used for tone squelch.
   Now I have to go and check the 706 and the TS-2000,
but I will be suprised if either allows two different
frequencies in "CT" mode.

73, Steve, K9DCI


--- "Wes Johnston, AI4PX" <wes at ai4px.com> wrote:

> Some radios do allow for a different pl for TX than
> RX, and in that case,
> set the RX pl tone to 100 and the TX pl tone to
> anything but 100hz.
> 
> Wes
> 
> 
> On 7/31/07, Robert Bruninga <bruninga at usna.edu>
> wrote:
> >
> > >>> How do we call CQ locally on APRS?
> > >>
> > >>Voice Alert.  Each of packet contains a 100 HZ
> tone which will
> > >>be heard [by] all surrounding APRS also running
> Voice Alert.
> > >
> > > I never quite got this.   In order for this to
> work,
> > > I'd need to run PL squelch, right?  So how,
> then,
> > > would my APRS station be able to hear, say, the
> > > local digi or WX station that *isn't*
> transmitting
> > > a PL of 100?
> >
> > The D7 and D700 take their TNC data from the radio
> receiver in
> > front of the CTCSS tone squelch.  The CTCSS tone
> squelch only
> > silences the speaker in the D7 and D700.  This is
> why we can get
> > dual use from the 144.39 APRS channel for both
> APRS data
> > (without PL) and for the occasional human-to-human
> voice call
> > with PL 100.
> >
> > Running Voice Alert in the mobile, is like adding
> another free
> > radio channel in the APRS mobile.  This
> hidden-back-channel is
> > for being able to make a voice call to such an
> operator on a
> > guaranteed known voice calling channel that you
> know he is
> > monitoring... Because you hear his (and only his)
> packet when he
> > is in SIMPLEX range (about 1 to 3 miles)...
> >
> > It works!
> >
> > But the WORST killer of this function is HOME
> stations or 24/7
> > parked cars that still TX their Voice Alert PL100
> packets
> > *without* an operator present.  This is very
> frustrating since
> > other voice alert mobiles that might be passing
> by, hear these
> > "CQ's" yet no one is listening in response.
> >
> > So remember, Voice Alert is a MOBILE-to-mobile
> system only.
> > Home stations that TX it continuously can kill the
> golden goose
> > due to QRM.  People willturn their APRS channel
> volume down and
> > forget about it, and then they also do not hear
> voice calls to
> > them.
> >
> > Of course you CAN monitor with CTCSS 100 from home
> for passing
> > simplex mobiles BUT ONLY IF YOU DO NOT TX PL100
> 24/7.  Problem
> > is that most radios cannot independently set their
> RX CTCSS
> > without also automatically enabling their TX PL...
>  This is why
> > we simply ask home stations to never TX with voice
> alert
> > enabled.
> >
> > Bob
> >
> >
> > _______________________________________________
> > aprssig mailing list
> > aprssig at lists.tapr.org
> >
>
https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
> >
> 
> 
> 
> -- 
> In theory there is no difference between practice
> and theory.
> > _______________________________________________
> aprssig mailing list
> aprssig at lists.tapr.org
>
https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
> 



       
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