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Post by Bill » Fri, 30 Nov 2007 13:49:54

What does it mean when I hear music like jingle (tone) lasting about a
second at the end of transmission?  Does it mean it is trunk
communication?  Any sites I can look up to learn more?

Thanks in advance.

-Bill

 
 
 

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Post by fred burges » Sat, 01 Dec 2007 02:16:16



Quote:> What does it mean when I hear music like jingle (tone) lasting about a
> second at the end of transmission?  Does it mean it is trunk
> communication?  Any sites I can look up to learn more?

> Thanks in advance.

> -Bill

It may very well be a trunk.  When the City Services here in Calgary
AB Canada, used the GE/Ericcson trunk, there was a jingle right after
each transmission, then the conversation hopped to the next
frequency.  It was totally annoying, and hard to scan.  Curious to
know what frequencies you are monitoring.  Here in Calgary, we have
now, trunks in 400, 800, and 900 mhz bands.
Fred Burgess
 
 
 

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Post by mikeFN » Sat, 01 Dec 2007 04:05:59

yep most prob
though could just be selcalor dtmf id  tones?

mike



>> What does it mean when I hear music like jingle (tone) lasting about a
>> second at the end of transmission?  Does it mean it is trunk
>> communication?  Any sites I can look up to learn more?

>> Thanks in advance.

>> -Bill

> It may very well be a trunk.  When the City Services here in Calgary
> AB Canada, used the GE/Ericcson trunk, there was a jingle right after
> each transmission, then the conversation hopped to the next
> frequency.  It was totally annoying, and hard to scan.  Curious to
> know what frequencies you are monitoring.  Here in Calgary, we have
> now, trunks in 400, 800, and 900 mhz bands.
> Fred Burgess

 
 
 

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Post by **THE-RFI-EMI-GUY* » Sat, 01 Dec 2007 10:40:33

Does it sound like "GE brings good things to life"??


>What does it mean when I hear music like jingle (tone) lasting about a
>second at the end of transmission?  Does it mean it is trunk
>communication?  Any sites I can look up to learn more?

>Thanks in advance.

>-Bill

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"?

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money"  ;-P

 
 
 

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Post by Bill » Sat, 01 Dec 2007 17:40:08


Quote:> It may very well be a trunk.  When the City Services here in Calgary
> AB Canada, used the GE/Ericcson trunk, there was a jingle right after
> each transmission, then the conversation hopped to the next
> frequency.  It was totally annoying, and hard to scan.  Curious to
> know what frequencies you are monitoring.  Here in Calgary, we have
> now, trunks in 400, 800, and 900 mhz bands.
> Fred Burgess

My QTH is currently Kathmandu and the frequency in question is
454.0000 MHz.  I can hear both parties chatter just fine (with no
hopping to other frequency).  However the parties do mention about
moving to different channel apparently to clear the channel.  I still
need to discover that new frequency though.

My question regarding trunk is pretty basic though.  From what I have
read trunking simply allows the efficient usage of frequency similar
like a PABX phone system.  If the conversation doesn't hop to other
frequency like you have mentioned, there is really no need to worry
too much, isn't it?

Maybe I will provide .mp3 of the jingle one of these days.

Thanks.

 
 
 

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Post by fred burges » Sun, 02 Dec 2007 02:18:59



> > It may very well be a trunk.  When the City Services here in Calgary
> > AB Canada, used the GE/Ericcson trunk, there was a jingle right after
> > each transmission, then the conversation hopped to the next
> > frequency.  It was totally annoying, and hard to scan.  Curious to
> > know what frequencies you are monitoring.  Here in Calgary, we have
> > now, trunks in 400, 800, and 900 mhz bands.
> > Fred Burgess

> My QTH is currently Kathmandu and the frequency in question is
> 454.0000 MHz.  I can hear both parties chatter just fine (with no
> hopping to other frequency).  However the parties do mention about
> moving to different channel apparently to clear the channel.  I still
> need to discover that new frequency though.

> My question regarding trunk is pretty basic though.  From what I have
> read trunking simply allows the efficient usage of frequency similar
> like a PABX phone system.  If the conversation doesn't hop to other
> frequency like you have mentioned, there is really no need to worry
> too much, isn't it?

> Maybe I will provide .mp3 of the jingle one of these days.

> Thanks.

It still may be a trunk, on some systems, the conversation can still
go on, for a considerable lenth of time, before hopping.  I would
still do a search, for other frequencies, to see if it is a trunk.
Fred Burgess
 
 
 

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Post by fred burges » Sun, 02 Dec 2007 02:21:11


> yep most prob
> though could just be selcalor dtmf id  tones?

> mike




> >> What does it mean when I hear music like jingle (tone) lasting about a
> >> second at the end of transmission?  Does it mean it is trunk
> >> communication?  Any sites I can look up to learn more?

> >> Thanks in advance.

> >> -Bill

> > It may very well be a trunk.  When the City Services here in Calgary
> > AB Canada, used the GE/Ericcson trunk, there was a jingle right after
> > each transmission, then the conversation hopped to the next
> > frequency.  It was totally annoying, and hard to scan.  Curious to
> > know what frequencies you are monitoring.  Here in Calgary, we have
> > now, trunks in 400, 800, and 900 mhz bands.
> > Fred Burgess- Hide quoted text -

> - Show quoted text -

Pardon this dumb question, but was is " selcalor" ? Thanks in advance.
Fred Burgess
 
 
 

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Post by Al Gilli » Sun, 02 Dec 2007 06:37:54



>> yep most prob
>> though could just be selcalor dtmf id  tones?

>> mike




>> >> What does it mean when I hear music like jingle (tone) lasting about a
>> >> second at the end of transmission?  Does it mean it is trunk
>> >> communication?  Any sites I can look up to learn more?

>> >> Thanks in advance.

>> >> -Bill

>> > It may very well be a trunk.  When the City Services here in Calgary
>> > AB Canada, used the GE/Ericcson trunk, there was a jingle right after
>> > each transmission, then the conversation hopped to the next
>> > frequency.  It was totally annoying, and hard to scan.  Curious to
>> > know what frequencies you are monitoring.  Here in Calgary, we have
>> > now, trunks in 400, 800, and 900 mhz bands.
>> > Fred Burgess- Hide quoted text -

>> - Show quoted text -

> Pardon this dumb question, but was is " selcalor" ? Thanks in advance.
> Fred Burgess

Hi Fred...

I'm guessing the OP intended to type selcal.  If so, that stands for
Selective Calling, a scheme where two audio tones sent before a conversation
starts "unlock" the receiver's squelch so the conversation can be heard.
Other radios on the frequency which receive those tones (the SelCal "code")
don't unlock and the conversation is unheard.  I've heard SelCal used when
aircraft control stations are calling trans-Pacific commercial aircraft.
http://en.wikipedia.org/wiki/Selective_calling provides a pretty good
explanation.

Al

 
 
 

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Post by fred burges » Mon, 03 Dec 2007 03:53:51





> >> yep most prob
> >> though could just be selcalor dtmf id  tones?

> >> mike




> >> >> What does it mean when I hear music like jingle (tone) lasting about a
> >> >> second at the end of transmission?  Does it mean it is trunk
> >> >> communication?  Any sites I can look up to learn more?

> >> >> Thanks in advance.

> >> >> -Bill

> >> > It may very well be a trunk.  When the City Services here in Calgary
> >> > AB Canada, used the GE/Ericcson trunk, there was a jingle right after
> >> > each transmission, then the conversation hopped to the next
> >> > frequency.  It was totally annoying, and hard to scan.  Curious to
> >> > know what frequencies you are monitoring.  Here in Calgary, we have
> >> > now, trunks in 400, 800, and 900 mhz bands.
> >> > Fred Burgess- Hide quoted text -

> >> - Show quoted text -

> > Pardon this dumb question, but was is " selcalor" ? Thanks in advance.
> > Fred Burgess

> Hi Fred...
> I'm guessing the OP intended to type selcal.  If so, that stands for
> Selective Calling, a scheme where two audio tones sent before a conversation
> starts "unlock" the receiver's squelch so the conversation can be heard.
> Other radios on the frequency which receive those tones (the SelCal "code")
> don't unlock and the conversation is unheard.  I've heard SelCal used when
> aircraft control stations are calling trans-Pacific commercial aircraft.http://en.wikipedia.org/wiki/Selective_callingprovides a pretty good
> explanation.

> Al- Hide quoted text -

> - Show quoted text -

Great, thanks for your reply.  I learn something new every day.
Fred Burgess
 
 
 

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Post by Bill » Mon, 03 Dec 2007 12:52:22


Quote:> I'm guessing the OP intended to type selcal.  If so, that stands for
> Selective Calling, a scheme where two audio tones sent before a conversation
> starts "unlock" the receiver's squelch so the conversation can be heard.
> Other radios on the frequency which receive those tones (the SelCal "code")
> don't unlock and the conversation is unheard.  I've heard SelCal used when
> aircraft control stations are calling trans-Pacific commercial aircraft.http://en.wikipedia.org/wiki/Selective_callingprovides a pretty good
> explanation.

> Al

Al,
That must be it then.  Thanks for your input.  There must be a tone
that my radio didn't pick up and instead picked only the ones at the
end of the conversation.  My only question is how a user would know
the frequency is in use?  Could there be some kind of indication
(maybe visual?) so he won't cause interference?  Thanks again.
-Bill
 
 
 

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Post by Al Gilli » Tue, 04 Dec 2007 12:23:57



>> I'm guessing the OP intended to type selcal.  If so, that stands for
>> Selective Calling, a scheme where two audio tones sent before a
>> conversation
>> starts "unlock" the receiver's squelch so the conversation can be heard.
>> Other radios on the frequency which receive those tones (the SelCal
>> "code")
>> don't unlock and the conversation is unheard.  I've heard SelCal used
>> when
>> aircraft control stations are calling trans-Pacific commercial
>> aircraft.http://en.wikipedia.org/wiki/Selective_callingprovides a pretty
>> good
>> explanation.

>> Al

> Al,
> That must be it then.  Thanks for your input.  There must be a tone
> that my radio didn't pick up and instead picked only the ones at the
> end of the conversation.  My only question is how a user would know
> the frequency is in use?  Could there be some kind of indication
> (maybe visual?) so he won't cause interference?  Thanks again.
> -Bill

I'm not sure how the tone frequencies are assigned but I'd guess it's done
much like assigning "squawk" codes for a RADAR transponder.  In that case
some FAA system assigns the code and marks the aircraft (in the computer)
with that code.  Then the Ground Control person radios the code to the pilot
along with taxi instructions they provide.  And it's likely that in the case
of airlines the pilot already has the four-digit code based on some sort of
flight instructions he receives from his company computer system.

That's my guess - anyone who knows more is please encouraged to post some
enlightening facts for us!