STM TETRA System

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CqDx

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Hi all

I did a quick stopover last week and picked up the following at moderate signal strength in downtown Montreal. I suspect this is the new STM TETRA System. No voice traffic is heard during the short time I was monitoring it.

Montreal Transport Agency Selects PowerTrunk TETRA Network


MCC 302
MNC 82
Location Area 120
860.0625 TCCH
862.4125 MCCH
 

mciupa

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When system becomes active, please advise and it will be added to the regular database.
 

mrscanner2008

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I follow STM TETRA system with TETRA TRUNK TRACKER but didn't hear nothing yet, no test, nothing.
 

EricCottrell

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Hello,

On a recent visit to L’Île au cône orange, I could only make a couple of quick spectrum recordings due to other activities. When I quickly reviewed the 800 MHz recordings, I noticed about a 20 KHz wide signal. I thought it sounded like TETRA on a STM frequency. When I googled it, it returned results about STM getting a new TETRA system. Then I found this thread.

Only a couple of frequencies were really strong. I noticed 859.2125 had a brief transmission so it is possible the system is active now. I am going to try setting up a TETRA decoder and seeing if I can decode anything.

The frequencies I noticed that could be TETRA are: 856.0375, 856.6625, 858.1875, 858.5375, 858.7375, 859.2125 Brief Tx (Voice channel?), 859.2375, 860.0625, 860.1875, 860.4875, 860.6625, 860.8625, 861.3125, 861.5125, 862.3625, 862.5625, 862.7125, 863.0125, 863.0625, 863.2625, 863.7125, and 864.7375. Some could be images as it seems like a lot of frequencies. Only a couple were really strong.

73 Eric
 

Ubbe

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Tetra uses 4 time slots and the frequency contaning the control channel slot are always transmitting. Some systems have their additional voice frequencies at the same site only go into transmit when the first channel have only one free slot, but the extra frequency will continue to transmit during a longer time after it is not used any more. So no brief transmission in Tetra systems. Even in simplex mode there are a master radio that acts as sync and transmits for at least 20 sec after everybody have stopped talking.

The bandwidth of the signal are 25KHz and are easily recognized if you have heard it before, or have listen to it from some sample files on youtube or sound sample webpages.

/Ubbe
 

EricCottrell

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Hello,

I am only getting TETRA control channels on STM frequencies (860.0625, 860.8625). The other frequencies I monitored are licensed to TELUS and sounds like a different transmission format. I am still getting activity on Site 3 of the STM EDACS system.

I still need to setup a TETRA decoder.

73 Eric
 

EricCottrell

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Hello,

Amazingly both the SDR# I/Q File and the File Player plugin can playback SDRPlay recorded IQ files!!! How does that happen?

So I was able to use the SDR# TETRA plugin and decode the two TETRA channels. It did not show any traffic. I do not know much about TETRA, but both frequencies show the main channel as 860.0625. I also noticed the base frequency is 800.0125 and using a 0.025 MHz step results in 2402 equaling 860.0625 MHz and 2434 equaling 860.8625 MHz. I did not notice any Neighbour Cell information.

860.0625 MCC: 302 MNC: 82 LA: 120 Color: 1 Main: 2402 Current: 2402
860.8625 MCC: 302 MNC: 82 LA: 120 Color: 1 Main: 2402 Current: 2434

SystemCode 2
ColorCode 1
SharingMode 0
TSReservedFrames 0
UPlaneDTX 0
Frame18Extension 0
MCC 302
MNC 82
NeighbourCellBroadcast 2
CellServiceLevel 0
LateEntryInfo 1
Main_Carrier 2402
Frequency_Band 8
Offset 3
Duplex_Spacing 1
Reverse_Operation 0
NumberOfCommon_SC 0
MS_TXPwr_Max_Cell 6
RXLevel_Access_Min 4
Access_Parameter 7
Radio_Downlink_Ttimeout 3
Hyperframe_or_Cipher_key_flag 0
Hyperframe 53433
Optional_field_flag 3
Optional_field_value 2048
Location_Area 120
Subscriber_Class 65535
Registration_required 1
De_registration_required 1
Priority_cell 0
Cell_never_uses_minimum_mode 1
Migration_supported 0
System_wide_services 1
TETRA_voice_service 1
Circuit_mode_data_service 1
SNDCP_Service 1
Air_interface_encryption 0
Advanced_link_supported 1
Authentication_required_on_cell 1
Security_Class_1_supported_on_cell 1
Security_Class_3_supported_on_cell 1


So we need to wait awhile longer.

73 Eric
 

DaveH

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The other signals which are 20-25kHz wide appear to be iDEN, or something else like it,
which is still around; licensed by Telus, for example:


Dave
 

EricCottrell

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Hello,

I was up in Montreal for a few days earlier this week and listened to 860.0625 with my AOR DV-1. I only heard a brief transmission that sounded like encrypted voice. Of course I get home and reviewed my spectrum recordings to find the Main Channel is now 860.8625. Still no voice activity heard on the spectrum recordings.

Main Carrier 2434 is 860.8625
2402 is 860.0625
LA is 120

There is Neighbor cell information being broadcast, but I did not see any of the frequencies during spectrum playback. The frequencies are licensed to STM in the Montreal area.
Neighbor cell
Cell ID LA Main Carrier
1 99 2557 863.9375
2 100 2547 863.6875
3 101 2491 862.2875
4 102 2557 863.9375
5 103 2579 864.4875
6 104 2547 863.6875
7 105 2582 864.5625

It appears the system is still in Build-Out.

73 Eric
 

mrscanner2008

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Hello,

I was up in Montreal for a few days earlier this week and listened to 860.0625 with my AOR DV-1. I only heard a brief transmission that sounded like encrypted voice. Of course I get home and reviewed my spectrum recordings to find the Main Channel is now 860.8625. Still no voice activity heard on the spectrum recordings.

Main Carrier 2434 is 860.8625
2402 is 860.0625
LA is 120

There is Neighbor cell information being broadcast, but I did not see any of the frequencies during spectrum playback. The frequencies are licensed to STM in the Montreal area.
Neighbor cell
Cell ID LA Main Carrier
1 99 2557 863.9375
2 100 2547 863.6875
3 101 2491 862.2875
4 102 2557 863.9375
5 103 2579 864.4875
6 104 2547 863.6875
7 105 2582 864.5625

It appears the system is still in Build-Out.

73 Eric
In your Info Cell ID 99 and 102 both have the same Main 2557.
Last time I check this system I found Main 2591 for Cell 99.
 

hermite

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In your Info Cell ID 99 and 102 both have the same Main 2557.
Last time I check this system I found Main 2591 for Cell 99.
I'm using Network Info pulled from SDR# Tetra plugin.
This is what I am seing today. (Cell ID #7 no longer active)
Main 2547 seems attributed to Cells 100 and 104.
Can someone confirm?
Cell IDNeighbor LAMain CarrierFrequency
1992557863.9375
21002547863.6875
31012491862.2875
41022591864.7775
51032615865.3775
61042547863.6875
 

EricCottrell

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Hello,

The different main channel is likely for the reasons we see on 860.0625 and 860.8625, the control channel changes. I looked at the licenses and the frequencies are usually paired. Also using the licenses, we are only seeing the tip of the iceberg (radio system). A lot of the sites are using Commscope RCT-7 1-5/8 inch Coaxial Radiating Cable, likely installed along the tunnels underground. I suspect there is at least 120 sites, with LA 120 serving the above-ground heavy maintenance and rail shop complex in Youville. Google satellite view shows some above-ground trackage.

The other frequencies in the neighbors list are used on the Blue line. There is a underground rail link to the heavy maintenance and rail shop complex on the blue line between De Castelnau and Parc. The neighbor list seems to fit with stations near the shop rail link.

863.9375/864.7875 5S46_SBR96 De Castelneau (Station)
862.1375/863.6875 5S44_SBR97 Parc (Station)
861.2375/862.2875 5S42_SBR98 Acadie (Station)
863.9375/864.7875 5S40_SBR99 Outremont (Station)

73 Eric
 

EricCottrell

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Hello,

I was able to download the Land Mobile TAFL files and sort out the STM allocations. Most of the licenses are for the Blue line, so the system is still in Build-Out. I was able to figure out some frequencies from the licenses. There are BDAs (Bi-Directional Amplifiers) licensed for some of the stations on the LA 120 frequency pair. There are 6 pairs of frequencies used for underground LAs, so they can assign different frequency pairs to adjacent LAs (like cellphone sites).

Possible DMO (Direct) All Units
858.3625

Mobiles (Above Ground)
860.0625R 860.8625R LA 120
862.1625R
862.4125R

Trains (Below Ground)
861.2375R 862.2875R LA Pair 1
862.1375R 863.6875R LA Pair 2
863.9375R 864.7875R LA Pair 3
864.0125R 865.0625R LA Pair 4
864.4875R 865.3875R LA Pair 5
864.5625R 865.8125R LA Pair 6

Portables licensed for DMO, Mobiles, and Trains frequencies.

73 Eric
 

EricCottrell

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Hello,

I expect more neighbors to pop up on the LA120 neighbor list as the Blue line sites are installed.

The licenses have an interesting reference designation. The first character appears to be the line (2 = Orange, 5 = Blue).
The second character appears to be the type of location (S = Station, N = Ventilation Station). The third and fourth characters appears to be a distance or sequence number, but I can not fit a unit of distance. The second grouping (SBRxxx) seems to match the LA, but so far in one case it does not. It does seem to be a sequence number.

Blue Line - Main (Southward)
864.4875R 865.3875R LA Pair 5 5N57_SBR91 Michel Ange (PVM)
863.9375R 864.7875R LA Pair 3 5S56_SBR92 Station Saint-Michel (Terminus)
861.2375R 862.2875R LA Pair 1 5S54_SBR93 D'Iberville (Station)
862.1375R 863.6875R LA Pair 2 5S52_SBR94 Fabre (Station)
863.9375R 864.7875R LA Pair 3 5S46_SBR96 De Castelneau (Station)
862.1375R 863.6875R LA Pair 2 5S44_SBR97 Parc (Station)
861.2375R 862.2875R LA Pair 1 5S42_SBR98 Acadie (Station)
863.9375R 864.7875R LA Pair 3 5S40_SBR99 Outremont (Station)
862.1375R 863.6875R LA Pair 2 5N39_SBR100 Davaar (PVM)
861.2375R 862.2875R LA Pair 1 5S38_SBR101 Édouard-Montpetit (Station)
863.9375R 864.7875R LA Pair 3 5S36_SBR102 Université-de-Montréal (Station)
864.4875R 865.3875R LA Pair 5 5S34_SBR103 Côte-des-Neiges (Station)
863.9375R 864.7875R LA Pair 3 2S36_SBR104 Snowdon (Terminus)
864.5625R 865.8125R LA Pair 6 5N31_SBR105 PVM Coolbrook (Poste ventilation mécanique)

Blue Line - Yard (between De Castelneau and Parc) (Westward)
864.4875R 865.3875R LA Pair 5 5N45_SBR110 Alexandra (PVM)
864.5625R 865.8125R LA Pair 6 5R45_SBR106 (Jarry, 80 Jarry Ouest)
861.2375R 862.2875R LA Pair 1 5N45_SBR107 Atelier Youville (Poste d'Épuisement)

Youville (STM Legendre)
862.1375R 863.6875R LA Pair 2 YU03_SBR109 Youville (Poste d'Épuisement)
864.0125R 865.0625R LA Pair 4 YR09_SBR108 (P.R. Legendre, 8845 Boul. St-Laurent)

It will be interesting to ride the Blue Line in the spring to see where there are active LAs and receive their neighbor lists.

73 Eric
 
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