Hi folks. My interest in radio is mainly from the point of view of
monitoring (ie with a scanner). I just got the news that Pittsfield Twp.
(where I live) is moving to a new "800 mhz" public safety communications
system. Well, I decided to look for them in the 800 mhz range, and 
except for cellular (in approx 860-920 mhz range) everything I heard
(mostly around 815 - 825 mhz) seems to be digital transmission,
and therefore unintelligible on an ordinary receiver.

Can anybody shed any light on this? Are the days of monitoring 
police / fire / public safety quickly coming to an end?

Also, any other discussion on scanning / monitoring welcome!

44 responses total.

PT is part of the countywide trunking system I do believe.

Thanks, and please excuse the next question - is the countywide
trunking system digital and un-monitorable?

The reason I ask is because there is a section in "Police Call"
entitled "You *can* monitor trunked systems" along with a detailed 
explanation that I did not quite understand.

Radio Shack sells a scanner designed to monitor trunked systems I seem
to recall.  I use to monitor the AA Police trunked system on my scanner
simply by programming in the 10 frequencies and scanning them.  I would
have to lock out the data channel of the day since that is just a bunch
of digital noise.  Occasionally I would also have to skip other channels
when they were sending data over them.  It was not a very relaxing task
as I had to attend to the scanner a lot.

OK, next question...  Is the county trunked system the same as the AA 
Police trunked system?

The same?  I don't think so.  I do know that the county sheriff and the
AA Police were putting up obsolete 400' towers all over so that they could
better communicate with one another and reduce the No of dead spots.

Does anybody have the freqs. for the 2 trunked systems?

Well, after a bit of research, I can answer my own questions.

Yes, there is only one trunked system. It is officially the AA police
trunked system, but almost all pulic service agencies in the county
are now using it. Pittsfield Township was the last to switch over, 
about 4-6 weeks ago. HVA is also on it, although you can also hear
them on thier old freqs. as well.

The freqs of the trunked system are:
851.0875
851.1875
851.2625
852.0875
852.1875
852.2625
853.0875
853.1875
853.2625
854.0875
854.1875
855.0875
855.1875

I'll look at my trunking scanner, and let you know what the fleet map
codes are (good only if you have a trunking scanner)

There are two trunking systems in Washtenaw County in Michigan.
The University of Michigan has their own system and
Washtenaw County has the other. The City of Ann Arbor
shares the Washtenaw County System. For an updated fleet
map, you can stop by our office at Communications Electronics,
Emergency Operations Center, 254 Wagner Road South in
Ann Arbor. Call me at 734-996-8888 if you need directions.
We have sold thousands of trunking scanners and it is very
easy to monitor. For more information about trunking scanners,
please visit the Communications Electronics web site at
http://www.usascan.com.  You can also get fleet map information
by visiting the Bearcat radio club web site at
http://www.bearcat1.com

Ann arbor's trunking fleet map is E1P2, same as what UM uses.  I found a great
Web page with all the michigan info on it.  I can't recall the URL, but I did
an Altavista search on "ann arbor" + "trunking", or something along those
lines.

http://members.aol.com/wwhitby2/trs.html
and
http://www.concentric.net/~Lsbutler/
have some interesting info.  The first link is the one I got all my info from.

This is some great info.
In just the last year I've gotten involved in scanning and right now
I am starting to flirt with ham.
I was suprised to find that some of the same poeple I've seen on grex
are also involved in local area radio.

Well, if you like to use technology to communicate over distances...

Ah!

I did some more poking around recently and discovered that the Ann Arbor and
UM systems now have a different fleet map than before.  Ypsi is now part of
the Ann Arbor system, and other communities have been added too.

Check out
http://www.trunktracker.com
for details.

Okay, I've got a BC235XLT, and on the new (and old for that matter)
fleet map listing it gives a figure of 0 and 7 for one of the
blocks.  How can I enter both numbers?!?  How are we supposed to
interpret this?  Actually it's two of the blocks, not one.

I just played with the possible combinations until the groups displayed best
matched the listings... like Ypsi using the 5 digit numbers instead of the
"400-1" style of Ann Arbor.

If you make both of those blocks (I forget which ones they are)
7 ypsi will show up at 522-x I think.

I've been putting "consumer" frequencies into my scanner lately.  

Just for grins, here's the "Family Radio Serivces" (FRS) frequencies:
CH - FREQ.
01 = 462.5625
02 = 462.5875
03 = 462.6125
04 = 462.6375
05 = 462.6625
06 = 462.6875
07 = 462.7125
08 = 467.5625
09 = 467.5875
10 = 467.6125
11 = 467.6375
12 = 467.6625
13 = 467.6875
14 = 467.7125

Do you know why they are in two groups 5 Mhz apart? It's just simplex,
isn't it? What's in between?

GMRS??
/

GMRS channels are actually interlaced (and in some cases overlap) with the
first seven FRS frequencies.  The spectrum between the two bands (462 and
467) is typically used for commercial 2-way systems.  Where I'm located
there are bus systems, school security, power company 2-way, and
medical dispatch, including helicopters.

Anyone know anything about this new "CB" band, made up of old public
service freqs in the HiVHF band?

There's an item in this conference on that, is there not?

Yep, I found it about 20 seconds after I posted #22.

Anyone have any idea what frequencies the Village of Pinckney
uses for their police operations?  I've been unable to find anything
by searching through frequency lists or listening.

Have you checked the FCC website?  Or the Percon Corp site?

Umm..er...;-)  I'll check the FCC now.  Percon is a pay site.  My fear is that
they are one of the communties that joined The State Police Digital trunked
system.

I didn't realize that the MSP now had digital system running.  I guess
that could account for the lack of activity on their old freqs.  :)

Yes, it is supposedly the largest such system in the country.  I guess we'll
just have to wait for Uniden to bring out their APCO 25 compatible digital
scanner.  IF that ever happens.

It's a big IF, at this point.

Uniden's BC785D scanner was announced at the CES, it will have the ability
to decode APCO25 signals.

I'm looking forward to the BC-785.  The county next to mine, which I'm
really close to, and I go on fire calls into occasionally, is running
on an digital trunked system.  (We're assuming it's APCO 25.)  I know
that when they come out, I'll have to go buy one from a place that isn't
right next to me here, since they'll not be able to keep them on the shelf.

I am too.  I now live in Livinston County which uses the State of Michigan's
statewide digital APCO25 system.

I haven't been keeping up, and didn't even know that they'd managed to
get that off the ground.

You would think that for a state-wide thing, they wouldn't go digital.

Get it off the ground?  It's been in place for a couple years now. There's
no MSP VHF low band activity anymore.  

One of my dad's friends is a maintainer for the State Police's radio
network.  It's actually pretty fascinating.  The acceptance test for it
involved dividing the lower peninsula up into squares and making sure
the system could be reached from inside every single square.  His
maintenance vehicle is a four-wheel-drive Suburban because some of the
towers are in rather remote locations.

Last I heard it didn't cover the U.P. yet, though, which is probably why
you still see patrol cars up there sporting the long VHF-Low antennas.

This system must've been awfully expensive, considering the amount of
sites required.  Anyone checked out their comms on this yet?

I'm sure it was, but it also carries some nice advantages.  For example,
they can tie a set of radios together into a 'private' channel, and they can
talk directly to each other from anywhere in the state.  It's not just a
sort of super linked repeater system, there's quite a bit of intelligence
involved, too.

I know some of the capabilites they have, since we had a truncked system
on my ship, that my division maintained.  What's funny about the linking
of these radios into a "private" channel, is that they think no one can
listen to them.  It doesn't help that Motorola uses a phone as the icon
for that feature.

- Backtalk version 1.3.30 - Copyright 1996-2006, Jan Wolter and Steve Weiss