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[aprssig] European 1750 question?

Steve Noskowicz noskosteve at yahoo.com
Mon Jun 21 15:14:53 UTC 2010



Mornin' Dave,

I'm not sure what your real question is, but...

> ... we use the term CTCSS "Continuious Tone Coded Subaudiable
> Squelch", I think in the US you call it "Pilot tone" or
> "PL".   

It's been a while since I worked on this, but as I recall, we called it "Continuious Tone Coded Squelch System".  I seem to remember that this was the international stantard's title.  Although I see from a current search on "CTCSS", your version is also used.

"PL" is Motorola's "Private Line"
IIR GE was "Channel Guard".  


The Wiki article appears to explain pretty well, though I didn't read it all.

http://en.wikipedia.org/wiki/CTCSS
73, Steve, K9DCI


> Most of
> the such equiped boxes will only radiate the tone on the
> output, when
> they are actually in use, not when just waking up to send
> an ID.   
> 
> On 70cms, things seem a little different, like no real
> changes, other
> than the addition of CTCSS access in many places. 
> There are no (that I
> know of) 12.5k channels used by us, as they are used by the
> "Primary
> User", it's a shared band here.
> 
> Note though, that some of the published information
> regarding which tone
> to use, is often way out of date, and some that have a tone
> shown as
> allocated, don't use it, such as GB3VA on 2m, that has no
> CTCSS systems
> at all.  (And never will, I'm
> told.)   You'll also find lots of
> repeaters listed, that just do not exist any more, due to
> site ownership
> changes, and the rental going sky high as a result..
> 
> Cheers.
> 
> Dave G0WBX.
> 
> 
> > -----Original Message-----
> > From: Pentti Gronlund [mailto:pentti.gronlund at tut.fi]
> 
> > Sent: 18 June 2010 16:38
> > To: bruninga at usna.edu
> > Cc: aprssig at tapr.org
> > Subject: Re: [aprssig] European 1750 question?
> > 
> > Robert Bruninga writes:
> > 
> > > In Europe (or anywhere else that whistle-up
> repeaters are used)...
> > 
> > Company-radio makers like Motorola call it single-tone
> access...
> > 
> > > Are ALL of these 1750 repeaters now
> narrowband?  (meaning 2.5 KHz 
> > > deviation or whatever is the European
> standard?).
> > 
> > Narrowband is quite rare. I believe it has been made 
> > compulsory in the UK and in Germany, everywhere else
> there 
> > can be narrowband machines but the default is wideband
> (3.5 
> > kHz nominal/5.0 kHz peak).
> > 
> > > Reason I ask, is that the APRS Freq Spec normally
> adds Txxx 
> > or Dxxx or 
> > > 1750 in a four byte field to indicate the type of
> squelch.  But it 
> > > also uses the FIRST letter to indicate wide or
> narrow band 
> > operation.  
> > > SO in the USA, we use Txxx or Dxxx.  But in
> narrowband 
> > countries they 
> > > would be txxx or dxxx.  But what about
> 1750?
> > > 
> > > Can we say that it now ALWAYS implies
> narrowband?
> > 
> > Nope.
> > 
> > Benjamin OH3BK
> > -- 
> >         Live Reports
> from the Taxman's Paradise!
> > 
> > 
> > 
> 
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