D&D Dispatch

A forum for discussion of the many trunked radio systems in and around our listening area.
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garys
SNE and Wiki Moderator
Posts: 3312
Joined: 29 Aug 2005 13:07

D&D Dispatch

#1 Post by garys » 05 Jan 2019 12:12

I came across 484.4625 while searching around with DSD+. It's a continuous signal, so it appears to be a control channel. DSD+ did not recognize it, so it's not DMR, NXDN, P25, or other know digital format. Unitrunker didn't recognize it either, so it doesn't seem to be Motorola analog or EDACS.

I found two listings for the frequency in MA, one for D&D Dispatch with a site originally listed as in Waltham, but with a pending modification to 200 Clarendon Street. There's a typo in the information as it lists that address in Waltham.

Anyway, for that site the following frequencies are listed,

471.8625
472.6625
482.9375
483.9625
484.3625
484.4625
484.5875
484.7625

Emissions type is listed as analog 5khz deviation.

If anyone has any ideas what this is, I'd be interested.
We're peace loving people, we're not hunting trouble, but if trouble should find us, we'll stand up and fight.

OceanNora
Posts: 74
Joined: 05 Mar 2018 12:57

Re: D&D Dispatch

#2 Post by OceanNora » 05 Jan 2019 20:55

That's the MPT-1327 system that's to my knowledge only used by who I believe to be Veterans Taxi. It appears that they have at least two talk groups, one for the dispatch side of the conversation and the other for the cab/The Ride side. Traffic on the voice channels sounds very similar to the GLSS or NEXT The Ride channels. They're the last system in our area I'm aware of that uses a trunking protocol that cannot be tracked by a x36 scanner since Harvard switched to Capacity Plus from PassPort.

garys
SNE and Wiki Moderator
Posts: 3312
Joined: 29 Aug 2005 13:07

Re: D&D Dispatch

#3 Post by garys » 06 Jan 2019 10:58

Thanks. Of course when I set up Unitrunker, I missed the MPT-1327 check box, so the program didn't recognize it. I have it running now, but there's been nothing but control channel since I set it up yesterday.

Not that I'm all that interested if that's the only user.

It seems that some cab companies still use the half duplex model, even though they are on systems that can run as repeaters. There's one that operates on one of the LTR systems north of Boston. I think it's the same one that Northeast Regional Ambulance uses, but it might be one of the other companies.

Odd system, but I guess that works for them.
We're peace loving people, we're not hunting trouble, but if trouble should find us, we'll stand up and fight.

scannermaster
Posts: 33
Joined: 26 May 2018 13:02

Re: D&D Dispatch

#4 Post by scannermaster » 08 Jan 2019 01:36

A number of years ago I rode in a Veterans Taxi and asked the driver to key up to check the freq. He was really hesitant to do so. He said that he was warned by management to only use the two-way in an emergency, otherwise use the cab data unit that they have. I gathered that they must be charged for voice activity on the system? For what that's worth.

Also, someone mentioned Harvard and Capacity Plus. I though they were using a UHF conventional channel for campus police with P25 encryption?

OceanNora
Posts: 74
Joined: 05 Mar 2018 12:57

Re: D&D Dispatch

#5 Post by OceanNora » 08 Jan 2019 21:27

That's interesting, that would suggest that they're using either a rented conventional frequency or rental trunked system such as this. The system is odd in that it seems to only have one user (whom I believe to be VTS) while at the same time being the only MPT-1327 in the area that anyone knows of. Most of the traffic that I've heard while scanning the frequencies conventionally sounds more like The Ride than normal taxi traffic.

GaryS, I'm interested to know if you had any luck following this system using Unitrunker. This system is one of the reasons I want to give the whole SDR thing a try.

As far as Harvard, the short version is yes, but the long version is that they use a whole variety of radio systems. Their police is UHF P-25 conventional with encryption while their non-sworn contract security for main campus is UHF P-25 in the clear. Their art museum, school of public health, and business school security are UHF DMR conventional in the clear. Their campus services (shuttle, facilities, events services) for the main campus are using a new UHF MotoTrbo Capacity Plus system that replaced an LTR PassPort system this past year. I submitted it in the data submission form, so I assume it's in the queue. Just to add more complexity, facilities also has at least one UHF analog channel still in use.

n1zyy
Posts: 79
Joined: 29 May 2017 20:56
Location: Lowell, MA

Re: D&D Dispatch

#6 Post by n1zyy » 13 Jan 2019 18:06

I've stumbled across the MPT-1327 system a handful of times while scanning the band.

It's super weird, maybe some sort of duplex system. The dispatcher will stayed keyed down for extended periods of time, sometimes not appearing to be talking to anyone. On all the MPT-1327 stuff, unkeying has some weird data sound that I assume is part of the trunking protocol.

Some of the licenses having a mailing address for some taxi or bus company in Waltham. (Maybe Veteran Taxi??? That's just off the top of my head.) I assume the move to Boston was another victim of that Antico Tower coming down.
Matt
Lowell, MA

OceanNora
Posts: 74
Joined: 05 Mar 2018 12:57

Re: D&D Dispatch

#7 Post by OceanNora » 15 Jan 2019 00:25

It's very odd, at times you'll be able to hear the driver speaking in the background presumably coming through a speaker at the dispatcher's desk. National Express had a similar duplex system when on the Comtronics analog system, but they went to a more conventional setup when the moved to the Connect Plus. It's a weird system in a lot of ways, there doesn't seem to be any other user than who I'm 99% sure is VTS's The Ride.

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