A Little More MBTA Radio System Info

[blantonl]

Note: this is a repost:

From: zerg90@webtv.net
Subject: [fr2] A Little More MBTA Radio System Info - Massachusetts


I spoke to both a Motorola rep and M/A_COM_rep._ It looks like
they are_going with M/A COM.

M/A COM was low bidder by a considerable bit in all parts of the
contract.
_
My understanding is that MBTA went to Florida to look at a M/A COM 3
site simulcast transit system.
_
The original bid was for equipment only.
_
3 site simulcast 800_EDACS_digital.
1_tunnel site
AVL with Siemens
_
There are going to be three more bids.
_
1.____Instalation of above equipment_
2.___ Design and equipment of antenna and coax for the tunnels
3.___ Installation of the tunnel antennas and coax
_
_
My understanding no scanner does EDACS digital.
_
You can repost this if you like.

 

[EricCottrell]

Hello,

I am hearing control channels on 866.150 and 867.150. They do not sound like EDACS control channels. They sound very similar to channels I heard down in PA and I suspect it is actually a MA/COM OpenSky system. Or is MA/COM using a new control channel format for Provoice?

73 Eric

 

[scannerfreak]

June 11, 2004

The work consists of the installing and testing a new
two-way, MA/COM 800 MHz, fully digital trunked radio
system complete with integrated Computer Aided Dispatch
and Automatic Vehicle Location Systems for the MBTA
transit system. This work also includes the installation of
400 MHz base stations for the Boston Fire Department.

http://www.mbta.com/business_t/pdf/NTB_N50CN01.pdf

Bids Must Be Received By: July 14, 2004 At 2 PM

 

[michaelbos]

The VA Police went to MA/COM for digital radios. They are junk, the system is junk. Prior on analog the divisions could talk to each other, now on digital, we cannot talk to each other at all, the Officer in trouble buttons don't work and the radio ID does not come up on the panel as the old motorla system :evil: did. The Transit Police think they have a bad system now, just wait. The Police union is filing safety charges against the VA since it's officer safety.

 

[PeterSz]

Michaelbox,- can you give us any freqs or locations? Peter S - Arlington MA

 

[PeterSz]

Eric C - is it possible that those 2 channels are used for a AVL system (that allows the buses to make the automated stop announcements). Peter S

 

[rpetro]

I know some MBTA cops. Will post when I hear info.

 

[EricCottrell]

Hello,

I am picking up an EDACS wide control channel on 866.9375 (LCN 0). Trunker gives the sysid as 0021. Frequency is licensed to MBTA. Looks like possibly Needham or Quincy. No Activity. Since trunker is decoding it I assume ESK is off.

73 Eric

 

[EricCottrell]

Hello,

The EDACS wide control channel on 866.9375 (LCN 0) is still there with no voice activity. It appears the transmitter is in the South Boston area. This is interesting because MBTA is licensed for this frequency in Lynn, Quincy, and Needham. The City of Boston is licensed for this frequency in Boston, but not for all the rest of the trunked frequencies.

73 Eric

 

[EricCottrell]

Hello,

I noticed today the EDACS control channel is on 867.1750 now. Still has LCN 0 and no voice activity.

73 Eric

 

[jack103]

I saw this item on the MBTA board of directors agenda today



" Authorization for the execution of a contract with Communications
International, Inc., of Vero Beach, Florida, to remove the
Authority's existing VHF/UHF radio system and install and test the
new M/A-COM 800 MHz, fully digital trunked radio system and other
ancillary services for a total cost not to exceed $7,895,026."

Does anyone have any info on Communications International Inc?Also note the"fully digital trunked radio system ect."

 

[crashcrew]

http://www.ask4cii.com/about.htm

 

[EricCottrell]

Hello,

The EDACS control channel is gone so I assume it was for testing. It appeared to be coming from the South Boston area rather than the licensed sites.

The AVL system is still going on 866.1750.

73 Eric

 

[EricCottrell]

Hello,

A few days ago a EDACS control channel appeared on 866.475. I finally got a chance to do a etrunker run and the sysid is the same as on the other frequency. Maybe they have the equipment installed at one of the sites, likely Quincy. 867.175 is still AVL. 866.4500, 866.9625, and 867.9375 are still being used for simulcast of the UHF frequencies.

There is regular keyups on several of the other frequencies. There is a brief digital burst that reminds me of how P25 sounds after the user unkeys. I suspect that this is the system testing the repeaters.

Logging with eedump shows a single line of data in the sea of system info with the comment Fragmented! after it. I suspect that these indicate the repeater tests. The data is the same except for a few bits and I was able to figure out the possible LCNs.

866.4750 LCN 01? Control Channel
866.2250 LCN 02
866.9375 LCN 03
866.9875 LCN 06
867.1750 LCN 07
867.2500 LCN 08
868.6625 LCN 09
868.7250 LCN 0a (10)
868.9000 LCN 0b (11)
868.9250 LCN 0f (15)

01 is likely the control channel. I did not see 04, 05, 0c, 0d, and 0e
come up so they may be the ones being used for simulcast or too weak to
copy here.

73 Eric

 

[PeterSz]

I can confirm that 866.9625 is patched to 31.14 today - seems to be Silver Line Ops - which I think might be patched to 472.5875 also.

 

[EricCottrell]

Hello,

I made a typo on the original LCN list. 866.9375 is LCN 5.

I had an old dump of the system previously and noticed a few differences in the data sent. This could be due to differences in programing but also could provide some clues on data format changes.

The first problem is the control channel LCN does not appear in the sysid message. The LCN is Zero which is not a valid LCN.

fd60121 fd60121 SysID f=0 id=33
111 111 010 11 00000 000 1 00 100001
	       LCN	 H SC Sys ID

The idle messages looks interesting because the second word is not the same as the first. Perhaps this message was extended to provide more information. The messages are different.

fc00000 600c1c5  Older Idle
fc00000 600c1c4  Newer Idle

011 000 000 00 01100 000 1 11 000101 Older (866.9375)
011 000 000 00 01100 000 1 11 000100 Newer (866.4750)

Looking at the message it seems the lower bits are the control channel LCN. It matches the 866.9375 LCN and 866.4750 would be LCN 4.

So my updated LCN list is
866.2250 LCN 02
866.4750 LCN 04
866.9375 LCN 05
866.9875 LCN 06
867.1750 LCN 07
867.2500 LCN 08
868.6625 LCN 09
868.7250 LCN 0a (10)
868.9000 LCN 0b (11)
868.9250 LCN 0f (15)

I also noticed that the older system sent 3 messages in rotation.

f880700 f880700
111 110 001 00 00000 011 1 00 000000
f88111b f88111b
111 110 001 00 00001 000 1 00 011011
f881202 f881202
111 110 001 00 00001 001 0 00 000010

and the new system only sends one.

f881001 f881001
111 110 001 00 00001 000 0 00 000001

These are likely status messages but I have not figured them out.

73 Eric

 

[EricCottrell]

Hello,

Control channel shifted to 866.4250 (a new channel) and I got a LCN of 3. It looks like a control channel rotation of 866.2250, 866.4250, and 866.4750 is now occuring. Expect 866.4750 this afternoon. I also noticed some additional status messages in the dump file last night.

This is looking more like a "real" site and not a test site. Site id is 33 (decimal).

Updated list is now:
866.2250 LCN 02
866.4250 LCN 03
866.4750 LCN 04
866.9375 LCN 05
866.9875 LCN 06
867.1750 LCN 07
867.2500 LCN 08
868.6625 LCN 09
868.7250 LCN 0a (10)
868.9000 LCN 0b (11)
868.9250 LCN 0f (15)

73 Eric

 

[EricCottrell]

Hello,

The site is back up to full power after spending a week at much reduced power. I am again getting almost 20 over 9 signals here on the North Shore. I noticed the system was not doing the channel tests last night and I did not notice any affiliations. I looked back in the logs and noticed two units were afflilating every 5 minutes or so. The bit patterns of the affiliations were close to the ones for the transmissions. It appears this was an external unit that affiliated with the system and briefly keyed up every 5 minutes or so. I see mention of a testing feature on EDACS that can check receivers through to transmitters. Likely a special radio that can monitor the system and check the RF and data stream.

Looking further into the bits it appears that the data format of the EDACS data stream has changed. I appears the changes support more radio ids, groups, and possibly frequencies. It may be an enhanced ProVoice networking option as some Provoice systems use the older protocol and some, like the systems in Cecil Co, MD and Mays Landing, NJ, appear to use a different format.

That is the reason the Data Channel LCN in etrunk shows up as zero. If more frequencies were supported then the size of the data field needs to be bigger. So they moved the Data Channel LCN field from the System ID message to another message. Supporting more radios and groups also needs bigger data fields so the fields where shifted around and redefined. I suspect they use the zero Data Channel LCN field in the data message to indicate that it is a new format as it is not a valid LCN value. The end result is the format is not backwards compatible.

So the bad news is that this system is not trunk trackable by scanners or etrunker. I am starting to modify eedump to see if I can make it work with the new formats. It may be possible to modify etrunker to support this as well. There has to be some more activity first.

73 Eric

 

[crash575]

Hi guys,

I own a radioshack Pro-94 scanner and I am trying to program in the MBTA’s trunked frequencies. I found the following list of frequencies at railroad.net:

866.1750
866.2250
866.4250
866.4500
866.4750
866.9375
866.9625
866.9875
867.1750
867.2500
867.4750
867.6625
867.9375
867.9750
868.4250
868.6625
868.7250
868.9000
868.9250
868.9500
866.975 (M/A-COM)

My first question is; are these correct (there appears to be more here than listed earlier in the thread)? Secondly I programmed these into my scanner as listed but I am unable to get anything other than data every now and then, would anyone know if there is a certain order they need to be entered in? Thanks in advance.

-Mike

 

[zerg901]

I searched between 866 Mhz and 869 Mhz the other day. 866.475 was the only MBTA freq that I heard in operation. It seemed to have a continuous low rumble. I suspect it might be part of the AVL (Automatic Vehicle Location) system. The T buses have PA systems that call out bus stops as the bus travels its route. I suspect this is tied to the AVL system. Peter S Arlington MA