[Scan-DC] "Motorboating"?

[Doug K.]

Thanks for all the answers - what I'm hearing sounds like an occasional open 
mike... wondering if it's only on VHF, and/or if it has to do with the D/A 
conversion - never heard anything like this before the 800 cutover.

Thx-

Doug

>From: Shawnerz <shawnerz@yahoo.com>
>To: scan-dc@mailman.qth.net
>Subject: Re: [Scan-DC] "Motorboating"?
>Date: Sat, 2 Aug 2003 21:47:05 -0700 (PDT)
>
>Doug,
>In this case, I think it's the 156.7 Hz PL (or CTCSS)
>tone you're hearing.
>-Shawn
>
>--- b_thom@juno.com wrote:
> >
> >
> > On Fri, 01 Aug 2003 22:51:34 -0400 "Doug K."
> > <oldsdoug@hotmail.com>
> > writes:
> > > All,
> > >
> > > When listening to Montgomery Fire (I'm still
> > listening on the VHF
> > > patch),
> > > will occasionally a "motorboating" sound (actually
> > sounds like a
> > > fire truck
> > > engine idling!)... I know there was a post about
> > this a few months
> > > ago here,
> > > but I'm sure I'll never find it!
> > >
> >
> > It was from April.
> >
> >
>http://mailman.qth.net/pipermail/scan-dc/2003/020474.html
> > Motorboating on the Alexandria TRS
> >
> > I said:
> >
> > >>
> > A few months ago, there was a discussion here
> > regarding motorboating
> > someone had heard while monitoring the Alexandria
> > TRS. He might have had
> > a PRO-2067, and he wondered if there was a problem
> > with his scanner.
> >
> > On Friday night, while driving around seeing if the
> > citizens of
> > Alexandria had thrown out anything good in their
> > trash, I found a pair of
> > Koss TD/65 headphones. I had to dig extra hard too,
> > as the headband had
> > become separated from the earpieces. Not only that,
> > but it was raining.
> >
> > Today I tested them by plugging them into my
> > recently purchased Bearcat
> > SC-180B, which, unlike my other scanners, has a
> > stereo headphone jack. I
> > found that the headphones work perfectly well.
> > Because the headphones
> > have better bass response than the itty-bitty
> > speaker in the SC-180B, I
> > was able to hear for the first time the motorboating
> > effect. It can be
> > heard in the background during the voice part of the
> > transmission. When
> > the voice stops, the frequency of the motorboating
> > increases to about
> > three times what it had been. This final burst at
> > the higher frequency
> > lasts for maybe a quarter-second before the
> > transmission ceases entirely
> > and the squelch tail is heard.
> >
> > I haven't tried Arlington's TRS to see if the
> > motorboating is there as
> > well. As other listers wrote in at the time, the
> > motorboating is part of
> > the Alexandria system and is not indicative of any
> > problem with the
> > scanner.
> >
> > HTH, as they say.
> > <<
> >
> > Shawnerz said:
> >
> > >>
> > Blair,
> > Like I said before, I'm pretty sure that's the 91 Hz
> > connect tone.  The tone at the end is a "signal" to
> > the receivers to mute.  That way there is no squelch
> > tail to the receiver that is expecting the "turn off
> > tone."
> > I'll have to poke around in the Motorola RSS.  There
> > are some confusing squelch/unsquelch/unmute/mute/And
> > unmute/And Unsqulech rules that can be established.
> > Perhaps someone else can explain them better.
> > -Shawn
> > <<
> >
> > Search the archives for Shawnerz and his earlier
> > comments on the subject.
> > _______________________________________________
> > Scan-DC mailing list
> > Scan-DC@mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/scan-dc
>
>
>__________________________________
>Do you Yahoo!?
>Yahoo! SiteBuilder - Free, easy-to-use web site design software
>http://sitebuilder.yahoo.com
>_______________________________________________
>Scan-DC mailing list
>Scan-DC@mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/scan-dc

_________________________________________________________________
The new MSN 8: advanced junk mail protection and 2 months FREE*  
http://join.msn.com/?page=features/junkmail