Listening to MBTA

[Railfan570]

I'm look to get into the MBTA trucked system to hear train and subway movement .. I love to hear dispatcher and engineers talking can anyone give me better frequencies to listen to for subway lines and commuter rail

Thank you
Big Railfan

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[ecps92]

The MBTA is using a Pro-Voice system
https://www.radioreference.com/apps/db/?sid=3476

I'm look to get into the MBTA trunked system to hear train and subway movement .. I love to hear dispatcher and engineers talking can anyone give me better frequencies to listen to for subway lines and commuter rail

Thank you
Big Railfan

Sent from my LGMP260 using Tapatalk

 

[EricCottrell]

Hello,

Only the Rapid Transit lines are using the Provoice Trunked Radio System. The Commuter Rail is still using the standard AAR Frequencies.

73 Eric

 

[garys]

As Eric points out, you'll hear the Rapid Transit lines, not Commuter Rail. You'll also here the bus lines, the Inspectors, and other management types.

 

[rosecitytransit]

I have a feed of the MBTA set up (when it's working) at RadioFeed Web Server using 2 RTL SDRs, Unitrunker and DSDPlus. However, the transmissions have been getting cut off. I'm not sure why as the signal and everything looks good. It was working better the last time I had it working, before they changed the control channel from 2 to 3.

 

[ecps92]

Where is your RX Site?

Your profile says you are in Oregon [little too far for 900 mhz]

The license for the MBTA TRS has multiple sites, could be the simulcast issue some folks encounter on the "M" TRS sites, all the ICE we have here in New England and/or ... so many possibilities.

I have a feed of the MBTA set up (when it's working) at RadioFeed Web Server using 2 RTL SDRs, Unitrunker and DSDPlus. However, the transmissions have been getting cut off. I'm not sure why as the signal and everything looks good. It was working better the last time I had it working, before they changed the control channel from 2 to 3.

 

[rosecitytransit]

It's in Sharon. The signal meter in Unitrunker looks great, but it's like it's cutting off each transmission after a few seconds. I am getting decoding errors in DSDPlus, but I don't think that's the problem. As I said, I wasn't having this issue before. I have remote access set up if someone wants to look at it.

It would also be nice to compare it to data coming from a real scanner. One possibility is that the system isn't sending continuation messages, which causes Unitrunker to think that the channel grant has ended. If so, I could set up things so the feed uses one dongle, switching the dongle between control channel and voice frequencies like a hardware scanner does.

 

[ecps92]

A long unanswered question is what Sites are they really using [Original license was from Boston to Canton, to Needham and Lynn]
Single site ? , Simulcast ? or... ? and maybe one of the sites is down or running lower power [seen that on the M systems in the past, where one channel is stronger than the others]

I don't have Provoice, so can't help, maybe one of the SNE members who live near-by and have Provoice might chime in...

It's in Sharon. The signal meter in Unitrunker looks great, but it's like it's cutting off each transmission after a few seconds. I am getting decoding errors in DSDPlus, but I don't think that's the problem. As I said, I wasn't having this issue before. I have remote access set up if someone wants to look at it.

It would also be nice to compare it to data coming from a real scanner. One possibility is that the system isn't sending continuation messages, which causes Unitrunker to think that the channel grant has ended. If so, I could set up things so the feed uses one dongle, switching the dongle between control channel and voice frequencies like a hardware scanner does.

 

[EricCottrell]

Hello,

I suspect they are running simulcast with the three sites as I have experienced simulcast-like issues. I am not too far from the Lynn site and confirmed the site was in use years ago. I have noticed some weird noises listening to the voice channels in analog when they drop transmission mixed into the standard EDACS end signal. Also EDACS is a 9600 bps signal and tends to need better signal for decoding than other trunked signals. You may have to try the typical "fixes" for simulcast problems. Also the RTL-SDRs maybe drifting or getting overloaded by a nearby signal.

I will give a listen, but my scanner tends not to have a problem.

73 Eric

 

[garys]

I live near Sharon and just turned on my 436HP and I'm hearing nothing. Last time I listened, a few weeks ago it worked okay. I checked the programming and it matches the Scan New England Wiki.

I also programmed my DSD+/SDR set up and dialed in 851.4250. There is signal there, but no decoded.

I'm at a loss to figure out what's going on. Maybe the data format has changed, but that seems very unlikely.

It's in Sharon. The signal meter in Unitrunker looks great, but it's like it's cutting off each transmission after a few seconds. I am getting decoding errors in DSDPlus, but I don't think that's the problem. As I said, I wasn't having this issue before. I have remote access set up if someone wants to look at it.

It would also be nice to compare it to data coming from a real scanner. One possibility is that the system isn't sending continuation messages, which causes Unitrunker to think that the channel grant has ended. If so, I could set up things so the feed uses one dongle, switching the dongle between control channel and voice frequencies like a hardware scanner does.

 

[rosecitytransit]

I also programmed my DSD+/SDR set up and dialed in 851.4250. There is signal there, but no decoded.

I'm at a loss to figure out what's going on. Maybe the data format has changed, but that seems very unlikely.

How do you have it set up? I believe that DSD+ can not decode the EDACS data protocol, and you have to use Unitunker for that and then feed the voice signal to DSD+ to listen. Note that Unitrunker thinks the site number is 33 and not 1 like is listed in the database, so what I had to do was to add the frequencies in the Limbo site that pops up (make sure "Discover" in the Receiver VCO is turned off).

 

[garys]

Ahhhh, that might explain why DSD+ doesn't decode the data channel, but does see the voice channels. How do I feed data from Unitrunker to DSD+?

I'll have to play with this a bit and see what I can come up with.

Turns out that the 436HP is fine, but there's a problem with the feed line off the splitter. I swapped that out and I'm getting the T no problem. TG 08-101 appears to be Radio Techs as they are talking about signal drop outs on the platform at a station.

 

[EricCottrell]

Hello,

The data field for the site number in Regular EDACS can support from 1 to 63. I think they only implemented a maximun of 28 or 30 sites. When they developed EDACS Extended Addressing (EA) the data field for the site number was expanded and the bit that represents 32 was set. This allows newer radios to detect if the system is using EA while not messing up older EDACS radios as the site number would not match. So Site 33 is really Site 1.
https://forums.radioreference.com/threads/edacs-extended-addressing-ea-decoding.180410/

73 Eric

 

[rosecitytransit]

Ahhhh, that might explain why DSD+ doesn't decode the data channel, but does see the voice channels. How do I feed data from Unitrunker to DSD+?

Use VB-Audio Virtual Cables It'll create audio input and output devices. Set Unitrunker to use the cable output device and DSD+ to use the cable input device.

And thanks for the tidbit, Eric.

 

[Railfan570]

This is great ! However i am in the Boston Massachusetts area and am trying to get MBTA Rail Frequencies that i can listen with a two way radio. I have heard Amtrak road frequency 160.920 which is okay, but i am looking for MBTA subways, Bus, commuter rail frequencys. My radio will handle the 160Mhz frequency railroad band and the 400 Mhz. Band range only.

Thank you
The Big Railfan. !!

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[garys]

In that case, you won't be able to hear anything with your existing radio.

 

[EricCottrell]

Hello,

160.920 is also used for MBTA commuter rail on the Franklin/Needham/Providence Line. Scan New England has a pretty good listing under Keolis Commuter Services.
Railroads - Scan New England Wiki

For Subways and Buses you need to upgrade to an Uniden scanner that offers a Provoice option.

73 Eric

 

[w1bp]

For rapid transit (subways and green line) and bus, you’ll need a scanner capable of receiving EDACS with the ProVoice upgrade. I can hear the rapid transit and bus MBTA EDACS system from Westford.

MBTA PD can be heard on UHF conventional, and also on the Mass State Police trunked radio system.

Finally, the commuter rail can be heard on 160 MHz AAR frequencies.


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[Railfan570]

Hello Everyone,
The Scan New Englad website was helpful. It lists the frequency for the things i was looking for... But subway is a other thing altogether.. To hear the subway and dispatchers talk is great to listen too.. And its great to have if something should happen..

The Big Railfan

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[ecps92]

And without a Radio that handles Provoice, many are out of luck.

However having the two T-Band Police channels and Boston Fire/EMS, we will know if something is occuring

Hello Everyone,
The Scan New Englad website was helpful. It lists the frequency for the things i was looking for... But subway is a other thing altogether.. To hear the subway and dispatchers talk is great to listen too.. And its great to have if something should happen..

The Big Railfan

Sent from my LGMP260 using Tapatalk