[Scan-DC] "Motorboating"?

[Shawnerz]

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.
> _______________________________________________
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> Scan-DC@mailman.qth.net
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