[aprssig] European 1750 question?

Dave Baxter dave at uk-ar.co.uk
Mon Jun 21 03:20:58 CDT 2010


I'm fairly sure all the 2m boxes in the UK are now using 2.5k deviation,
or at least should be!
Those on the original 25k channels, can use a 1750 burst, or CTCSS for
access.   Those "new" boxes that appeared on the "fill-in" 12.5k
channels, *Must only* use CTCSS for access.

Over hear, we use the term CTCSS "Continuious Tone Coded Subaudiable
Squelch", I think in the US you call it "Pilot tone" or "PL".   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to use, is often way out of date, and some that have a tone shown as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..


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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