County Comms NXDN (System 90)

A forum for the discussion of APCO-2, DMR, NXDN, and any other type of digital radio systems in our monitoring area.
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n1zyy
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Location: Lowell, MA

County Comms NXDN (System 90)

#1 Post by n1zyy » 03 Dec 2018 14:39

http://www.scan-ne.net/wiki/index.php?t ... unications

I just purchased the NXDN upgrade for my 536HP and have been tinkering around with it. I'm new to NXDN but have read a little bit in the past.

I found WPNZ335 for the one Goffstown frequency on our wiki, which revealed a total of five frequencies. I programmed them up and LCN Finder showed me 453.5625 as "LCN" 606. It hasn't found anything on the other 4. We also show 453.5625 / 606 as being in Georgetown, and I see it licensed there too (WNIB395).

The "System Status" view of the Goffstown system shows system ID of 5Ah (which would be 90 decimal, as we have), and a site ID of 3, plus a RAN of 3. The site ID matches what we have for Goffstown, but the RAN does not. (Though on the other 2 sites, RAN seems to match site ID.)

My understanding is that the "LCN" is actually a coded version of the frequency, which makes me wonder -- if I only have the LCN of the control channel, should the scanner be able to figure out the rest like it can for a SmartZone system?

n1zyy
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Re: County Comms NXDN (System 90)

#2 Post by n1zyy » 03 Dec 2018 15:08

Huh, the "System Status" tool on my scanner shows me how many frequencies it knows about. Goffstown and Framingham both show 1 frequency only, while Georgetown shows 6. It seems to instantly come up with this regardless of whether I have all frequencies programmed (I have 3 with LCNs for Framingham, and 5 but only one LCN for Uncanoonuc), so I suspect the controller broadcasts a list of all frequencies (or their LCNs) and their status, which is what the System Status page shows.

I have no idea how my scanner is receiving Georgetown fine but also seeing 453.5625 as Goffstown; I haven't programmed any RAN filters or anything.

n1zyy
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Re: County Comms NXDN (System 90)

#3 Post by n1zyy » 03 Dec 2018 23:03

Not putting this reply in Data Submission since it's kind of vague and I want to let it cook a bit and see if anyone has additional data. But, after I got the Georgetown Nexedge site programmed up, I ran Discovery on it and found the following users:

TG 2 - 147 hits - ID'd already as "NRT Bus - Masconomet Regional School District," which is definitely correct as the users were definitely buses and some ID'd as "Masco [whatever]."

TG 3 - 15 hits - Possibly school buses? Caught some references to drivers and monitors.

TG 6 - 120 hits - ID'd as "NRT Bus - Lowell School Buses" which seems correct. References to several Lowell schools.

TG 8 - 174 hits - Currently "Unknown," but sounds like buses. Some references to CREST Collaborative school in Methuen.

TG 10 - 13 hits - Also possibly buses or some type of student transport; talk of a parent worried about where their kid was and a location update.

TG 11 - 142 hits - Already ID'd as "UMass Lowell Shuttle," which seems consistent with what I heard. Occasional references to streets in Lowell, but usually calling out just "North" or "South" etc., presumably parts of campus. (I'm confused because UML also has another shuttle that's on analog FM which I heard just recently. Are there two separate shuttles?)

TG 13 - ? hits - Already ID'd as NRT Chelmsford. This happened to be really active when I was first starting the scan so I locked it out.

TG 500 - 29 hits - Already ID'd as "Tow/Auto Service Company" which I agree with. Addresses in Danvers and Peabody given.

TG 600 - 28 hits - Ambulances. Didn't hear any dispatches, though I didn't monitor for too long. Largely just calling in "occupied" or clear. One destination was "LGH Main," possibly Lowell General since they have the "Main" and Saint's campuses, but I'm not positive.

TG 700 - 410 hits - Already ID's as "Cab Company," which sounds right. That said, I did hear reference to "loading" and something about a chair, and one destination was a medical facility, so there's a chance the place also does some sort of chair car service?

TG 800 - 145 hits - ID'd as "Cab Company" as well, which I agree with.

TG 900 - 49 hits - Sounds like towing; references to AAA as well as an illegally-parked car needing to be removed. Locations in Methuen, Rockport, and Lynn referenced.

TG 1000 - 89 hits - Student transport / buses. Referenced a couple addresses in Lowell.

TG 1100 - 30 hits - I suspect school buses; heard "13", "19", and "21" calling "Base". Didn't catch any locations.

TG 1200 - 61 hits - ID'd as "Van Service." References to students having assigned seats on a bus/van. (I suspect several of the 'bus' companies may be using vans / etc., as several seemed to refer to students on a first-name basis.)

TG 1300 - 2 hits - Got absolutely no context clues on what this is, but the talkgroup exists.

The "hits" is how often it came up in Discovery mode; really only useful as a relative gauge of busy-ness. It was on for a couple hours this afternoon, which probably over-emphasizes the student transportation companies.

OceanNora
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Re: County Comms NXDN (System 90)

#4 Post by OceanNora » 04 Dec 2018 00:23

From my monitoring, 700 and 800 are both cab companies in the North Shore area, possibly the same company . Locations mentioned by both include Peabody, Lynn, Beverly, Danvers, and Middleton. Both mention "Staying in Peabody or going to Beverly," I've gotten Car #s 1-15. Based on all that, my educated guess is Tri-City Taxi which has offices in Peabody and Beverly among others.

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garys
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Re: County Comms NXDN (System 90)

#5 Post by garys » 04 Dec 2018 15:56

The channel line up I have it,

Channel Frequency
23 451.275
461 461.750
606 463.5625
631 463.8750
739 470.2125
978 484.2975

NXDN systems broadcast the channel number and there are a couple of formulae you can use to calculate the frequencies. They work well up to 470.000, but above that there is some guess work involved (at least for me) because the channel numbers are custom and don't use the regular formula.

w1hbu is very good at figuring this stuff out and I've learned a lot by reading his posts. Especially so when it comes to using SDR/DSD+. I haven't tried to figure out channel numbering using the LCN finder in the x36HP scanners for NXDN.

The NXDN systems I've seen match the RAN to the the Site number. In this case, the RAN should be 1. I don't know if that is a hard and fast rule or just how providers tend to do it. RAN is like Digital Color Code for DMR systems.

Since I can only hear the system infrequently, I don't have a lot of information as to users. I do remember hearing the cab companies one time.

I'll add this system to my x36Hp programming and listen next time I'm within range to see if I can figure out who the ambulance company is.

I suspect that the SMR providers are trying to get their customers to move from the analog LTR systems to DMR or NXDN.

n1zyy
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Re: County Comms NXDN (System 90)

#6 Post by n1zyy » 05 Dec 2018 01:07

Oddly, I had no luck with LCN finder on analyze or with Discovery. When I ran the system in ID Search mode out in the Weston area, I got all sort of hits. I'll have to play with that a bit more. If I have time tomorrow, I'm going to sit at the top of a hill in that area and see if I can figure that out.

I was getting hills as far down as Randolph on route 24, which surprised me. Then again, it's UHF not 800 or 900.

There's a growing demand for radio communications, but users seem to want AVL, messaging, and private message features, which analog can't deliver. So, digital will be the way moving forward. I think that many of the LTR users have moved to digital systems, and more will follow.

Nobscot Hill traffic is minimal, at best. I've listened on a hill not very far from there and get nothing for long periods of time on this system.




Interesting notes about 700 and 800 possibly being the same system, OceanNora. I don't know the area too well but your evidence sounds good to me.

Gary, your lineup matches what I found for the Georgetown with the LCN finder (which, in turns, matches the wiki). Seems like LCN Finder works pretty well on NXDN after all, as long as there's some activity for it to see. I'd read a bit about DSD+ and such, but never got around to setting it up. I hadn't realized that the NXDN update was available for the 436/536HPs until the other day so now I'm trying to work through some of these and see what I can hear.

I am yet to hear anything but the control channel on the Nobscot Hill or Goffstown site; will need to do more monitoring on those and see what turns up.

I play with DMR on the ham side and it's a neat technology. (As is NXDN; it's just not as popular on the ham side around here.) If I were putting up a new trunking system I'd certainly go that way, both for two slots in one frequency and for the ability to have stuff like GPS/AVL on top of it as a value-add. But for an LTR operator, I feel like you've probably paid off the equipment long ago, leaving the system a bit of a cash cow. The existing LTR systems around here don't seem to be running anywhere near capacity, so I'm not sure I'd see the urgency around upgrading to one of the digital systems right away. I don't see private LMR systems as a growing field, sadly.

As much as I prefer the audio quality of a strong analog signal, I see the benefit of digital living in an area with somewhat weak coverage of this system. It's strong enough that I seem to have 100% decode of the signal, while there's a fair bit of noise on the analog systems up there. There's a good range of copyable-but-annoying on analog that just sounds perfect on digital.

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garys
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Re: County Comms NXDN (System 90)

#7 Post by garys » 06 Dec 2018 13:03

TG 8 has a unit with an Alias of "Trombley Base." Trombley is a bus company on the north shore, right? It sounds like some kind of shuttle operation as the dispatcher is telling a unit to put an address into his GPS.

A nice thing about NXDN is that it usually broadcasts and Alias for subscriber radios.

Right now I'm using DSD+ to listen to the system. Coverage in Weston up at the reservoir is spotting on some of the voice channels. That's probably due to differences in output power. I'll try a different spot a bit further north next week.

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garys
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Re: County Comms NXDN (System 90)

#8 Post by garys » 06 Dec 2018 15:01

garys wrote:
06 Dec 2018 13:03
TG 8 has a unit with an Alias of "Trombley Base." Trombley is a bus company on the north shore, right? It sounds like some kind of shuttle operation as the dispatcher is telling a unit to put an address into his GPS.

A nice thing about NXDN is that it usually broadcasts and Alias for subscriber radios.

Right now I'm using DSD+ to listen to the system. Coverage in Weston up at the reservoir is spotty on some of the voice channels. That's probably due to differences in output power. I'll try a different spot a bit further north next week.

MASSBUSMARK
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Re: County Comms NXDN (System 90)

#9 Post by MASSBUSMARK » 06 Dec 2018 21:03

Trombly is a school bus and special ed bus/van operator based in Dracut, that is owned by NRT Bus. They have the contracts for Methuen and Andover Public Schools and Greater Lawrence Technical High School. Those buses are/were on 452.675 PL 192.8, don't know if that's still active.

TG3 is NRT Bus, don't know which yard. I did hear base call a driver to have her go to the North Andover yard and pick up a driver there to bring back to base. NRT's North Andover buses are on the ICE 900 DMR. NRT has the Georgetown Schools contract, I have a hunch it could be the Georgetown yard, but will work to confirm.

The ambulances on TG6 may be Pulse EMS, a small company (5 or 6 ambulances) based in Lowell that does transfers, no 911 work. They have Kenwood mobiles. I locked in on them, not much activity, heard A-4 and A-6 clearing Lowell General Main, their ambulances are numbered starting with A. Will work to try to confirm this.

TG1000 may be Community Teamwork Inc day care buses and vans, based in Lowell. They also have Kenwood mobiles. Will also work to try to confirm.

TG1200 may be a special ed van or bus company, heard unit call base to say I'm at the YMCA dropping off that child.

Just put TG 1100 in my TRX-1, will see what I can get to figure out who that may be.
Mark

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garys
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Re: County Comms NXDN (System 90)

#10 Post by garys » 06 Dec 2018 21:47

Is that TG6 or TG600 for Pulse?

I didn't see any hits on 600, but noticed a few on 6.

n1zyy
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Re: County Comms NXDN (System 90)

#11 Post by n1zyy » 06 Dec 2018 22:32

n1zyy wrote:
05 Dec 2018 01:07
Oddly, I had no luck with LCN finder on analyze or with Discovery. When I ran the system in ID Search mode out in the Weston area, I got all sort of hits. I'll have to play with that a bit more. If I have time tomorrow, I'm going to sit at the top of a hill in that area and see if I can figure that out.

I was getting hills as far down as Randolph on route 24, which surprised me. Then again, it's UHF not 800 or 900.

There's a growing demand for radio communications, but users seem to want AVL, messaging, and private message features, which analog can't deliver. So, digital will be the way moving forward. I think that many of the LTR users have moved to digital systems, and more will follow.

Nobscot Hill traffic is minimal, at best. I've listened on a hill not very far from there and get nothing for long periods of time on this system.
I didn't write that quoted part of my post. I wonder if my post and one of garys's got somehow mashed together into one? Darn computers!

My scanner only shows the text aliases while I'm actually scanning; they're not easy to review if you play back from Discovery. Paying attention to this while scanning a bit will likely be a big help in IDs.

This is a lot of good tentative IDs on some of these users. I'll let the scanner run a while more and see what I can find to help nail down some of these. I think 600 being Pulse is possible. I know PrideStar is on the Hudson LTR system and Trinity has their own crazy mishmash of stuff, but I've seen Pulse around town and wondered what they use.

I left LCN Finder on the Gofftsown/Uncanoonuc site for several hours tonight and it found nothing but the control channel, 452.0625 = LCN 86. It's RAN and Site ID of 3, though.

I want to try to find this Boston site their map suggests might exist and see if it's active.

MASSBUSMARK
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Re: County Comms NXDN (System 90)

#12 Post by MASSBUSMARK » 08 Dec 2018 10:09

I meant to write TG 600 is possibly Pulse EMS, sorry for the error on my part. TG 6 is NRT Lowell Public School buses as confirmed previously.
I don't believe there's a way to get text aliases on the TRX-1, at least not from what I could determine reading the users manual.
Mark

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garys
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Re: County Comms NXDN (System 90)

#13 Post by garys » 09 Dec 2018 18:09

According to their Facebook page, Pulse has 10 ambulances. No mention that I saw of the number of chair cars, but there were a couple of pictures so they have some. BLS only at this point, but I think OEMS requires a new ambulance service to work at the BLS level for at least a couple of years before they can apply for an ALS license.

So, if you hear Ambulance 1-10 and no ALS, it's most likely going to be them.
MASSBUSMARK wrote:
08 Dec 2018 10:09
I meant to write TG 600 is possibly Pulse EMS, sorry for the error on my part. TG 6 is NRT Lowell Public School buses as confirmed previously.
I don't believe there's a way to get text aliases on the TRX-1, at least not from what I could determine reading the users manual.
Mark

n1zyy
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Re: County Comms NXDN (System 90)

#14 Post by n1zyy » 10 Dec 2018 11:08

OceanNora wrote:
04 Dec 2018 00:23
From my monitoring, 700 and 800 are both cab companies in the North Shore area, possibly the same company . Locations mentioned by both include Peabody, Lynn, Beverly, Danvers, and Middleton. Both mention "Staying in Peabody or going to Beverly," I've gotten Car #s 1-15. Based on all that, my educated guess is Tri-City Taxi which has offices in Peabody and Beverly among others.
I did some more monitoring over the weekend. I believe they are indeed the same company. The dispatcher sounded the same on both channels.

Unit numbering might be more on the radio company than the customer, but 750 and 850 are both "Base", and both have x01 = Car 1, x02 = Car 2, etc.

I haven't yet tried to figure out how they have the channels split up, though it's not the usual duplex arrangement.

I'm going to spend some more time trying to identify the others, too.

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garys
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Re: County Comms NXDN (System 90)

#15 Post by garys » 12 Dec 2018 15:54

Did some more listening today on my SDR set up.

TG 700 and TG1400 use AVL and DSD displays the lat/long.
TG 600 is definitely an ambulance company, but isn't all that busy. I heard one transmission in an hour of listening. The Alias was "Amb2". Still didn't get a positive ID.
TG 800 seemed like a chair van service, more than just a taxi service.

Overall, the system is getting more and more busy, or so it seems.

If I have time, I'll get up north a bit tomorrow and listen in some more.

I also have to sort out the programming on my 536HP, as I get nothing on that. If I think of it, I'll bring my 436HP with me since for some reason that works better on this system.

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