[TrunkCom] 220Mhz systems

[Gary Hahn]

1. The 220 systems I'm aware of are older installed base than any digital
systems I'm aware of.  I believe the ones in Milwaukee have been around at
least as long as State of MI digital system, which was pretty much a pioneer
in digital for the US.

2. You say it's a step back, but name one tangible benefit of digital voice
as it exists today, much less over the last 5 years?  Same bandwidth, no
benefit in privacy, and very arguable benefit in voice quality (worse for
short distance comms). The 220 MHz systems are for businesses...they can't
afford to spend as frivously as the government does.  You will not get a
private business to spend 3000 or 4000 bucks per radio!  A few hundred, yes.

Gary

> -----Original Message-----
> From: trunkcom-bounces at mailman.qth.net 
> [mailto:trunkcom-bounces at mailman.qth.net] On Behalf Of Jeff Kenyon
> Sent: Sunday, October 24, 2004 11:10 PM
> To: Discussion of Monitoring Trunk Radio Systems
> Subject: RE: [TrunkCom] MPT1327 information
> 
> 
> I will take a listen.  On another note, has anyone heard 
> these types of systems from a distance?  I haven't spent much 
> time with this band, but in terms of the modulation I think 
> that the  makers are taking a step back, and had always been 
> under the impression that these systems were digital.
> 
> 
> 
> 
> 
> On Sun, 24 Oct 2004, Gary Hahn wrote:
> 
> > Compare to the following sound samples...
> >
> > http://kb9ukd.com/digital/220pilot.wav As heard in NFM, but 
> actually 
> > uses ACSB (similar to SSB) for voice comms. The pilot tone is 
> > transmitted about every 10 seconds.  In Milwaukee, 220.0125 is one 
> > frequency, but you may have to tune up or down a bit to hear it.  
> > Sorry for the scratchy copy, I'll work on a better sample.
> >
> > http://kb9ukd.com/digital/mpt_1327.wav is MPT1327, but I 
> didn't think 
> > it was associated with ACSB modulation.
> >
> > Gary
> >
> > > -----Original Message-----
> > > From: trunkcom-bounces at mailman.qth.net 
> > > [mailto:trunkcom-bounces at mailman.qth.net] On Behalf Of Jeff Kenyon
> > > Sent: Sunday, October 24, 2004 10:55 PM
> > > To: Discussion of Monitoring Trunk Radio Systems
> > > Subject: RE: [TrunkCom] MPT1327 information
> > >
> > >
> > > Well, I don't know.  These systems are broadcasting in 
> ACSSB, and I 
> > > hear what seems to be a regular control channel  I also 
> am hearing 
> > > data bursts here  The systems listed on the web are MPT-1327 
> > > systems.
> > >
> > >
> > >
> > >
> > >
> > > On Sun, 24 Oct 2004, Gary Hahn wrote:
> > >
> > > > Bear in mind this topic split from the original.  The 
> 220 systems 
> > > > discussed most likely are not MPT1327, rather SEA radio's LTR 
> > > > clone protocol(someone can correct me on the details there...).
> > > >
> > > > Nonetheless, nice links for the MPT1327 stuff!
> > > >
> > > > Gary
> > > >
> > > > > -----Original Message-----
> > > > > From: trunkcom-bounces at mailman.qth.net 
> > > > > [mailto:trunkcom-bounces at mailman.qth.net] On Behalf Of Mike 
> > > > > Agner
> > > > > Sent: Sunday, October 24, 2004 5:39 PM
> > > > > To: Scan-L at listserv.uark.edu
> > > > > Cc: trunkcom at mailman.qth.net
> > > > > Subject: [TrunkCom] MPT1327 information
> > > > >
> > > > >
> > > > >    Since there seemed to be a little interest in this mode, I 
> > > > > thought I might throw out a couple of notions about decoding 
> > > > > packages and such...
> > > > >
> > > > >    Apart from the Winradio module for Moto and MPT
> > > trunking, there
> > > > > are a few other packages - some even with Yahoo 
> support groups - 
> > > > > that you can find links  for here:
> > > > >
> > > > >
> > > http://www.strongsignals.net/access/content/software.html#DECODE
> > > > >
> > > > >    Interestingly, some can use the discriminator output, but 
> > > > > most seem to be able to handle tapping the speaker 
> out for the 
> > > > > audio. Some seem to need some sort of external modem circuit, 
> > > > > not unlike the kind of setup you would
> > > > > use for Trunker.
> > > > >    Don't forget - there is a dedicated forum on Radio
> > > > > Reference for MPT1327,
> > > > >
> > > > >    73s Mike
> > > > >
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