[Scan-DC] Fairfax Dispatch - 460.575

[Shawnerz]

Randy,
You're right, I'm wrong.  If it were SCADA or 
encrypted traffic, you would hear some sort of
"noise."
It could be some slow speed data, but I doubt it.  It
probably is some sort of interference or system
malfunction.
-Shawn 

--- Randy Benn <randybenn at gmail.com> wrote:

> Shawn,
> 
> Interesting possibilities.
> 
> Do you think they would put the SCADA traffic out on
> the conventional 
> dispatch freq.?  Also, even if it were SCADA
> traffic, I would expect some 
> kind of modem-like audio.  When the squelch breaks,
> it is just silence, like 
> someone keying a mic, then not taking.  Also, I
> don't think it would be 
> encrypted traffic, for essentially the same
> reasoning; even if it were 
> encrypted traffic, I would expect to hear something,
> not a silent carrier.
> 
> Randy
> 
> ----- Original Message ----- 
> From: "Shawnerz" <shawnerz at yahoo.com>
> To: "Randy Benn" <randybenn at gmail.com>; "scan dc"
> <scan-dc at mailman.qth.net>
> Sent: Monday, July 10, 2006 4:33 PM
> Subject: Re: [Scan-DC] Fairfax Dispatch - 460.575
> 
> 
> >
> > Randy,
> > I don't monitor the system, but there are a couple
> > possibilities:
> > 1.  It could be interference.  For whatever
> reason,
> > the base station "sees" the interference
> (intermod,
> > adjacent channel, whatever) as a valid signal and
> is
> > repeating it.  In the scenario, the system
> controller
> > would show the repeater as busy and it would not
> be
> > availible for use while the interference is
> active.
> > 2.  It could encrypted traffic and you're hearing
> the
> > encrypted output.
> > 3.  It's analog SCADA (Station Control And Data
> > Automation) traffic.  For example, in Montgomery
> > County, they use SCADA units to report water well
> > alarms, flow rates and stuff like that.  The units
> > have their own talkgroup and the demodulated audio
> > resembles static to the untrained ear.
> >
> > I hope that helps.
> > -Shawn
> > --- Randy Benn <randybenn at gmail.com> wrote:
> >
> >> I've recently been monitoring FFX dispatch on
> their
> >> conventional freq. rather than the TRS.  I've
> >> noticed a strange behavior in that the squelch
> will
> >> frequently break, but there is no audio that
> >> follows.  This has been verified on multiple
> radios
> >> and in multiple locations, so it doesn't seem to
> be
> >> related to interference in any way.  I haven't
> >> noticed this behavior on 4A on the TRS, so it
> seems
> >> to be limited to the conventional alerting freq.
> >> Anybody know what might be going on?
> >>
> >> Randy
> >> _______________________________________________
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> >>
> >
> >
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