So I have an interesting question about London Transit. When dispatch is contacting a bus, just as an example bus 315, how are they able to only contact that bus, and not have the whole fleet's radios going off? Are they using some sort of selective calling? and if thats the case, how is it you don't hear any selcall tones when listening to them?
Question about London Transit
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DaveH
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Are they using London P25 system (don't see them listed there)...? They could be using I-calls. Ottawa extensively used I-calls (albeit on EDACS) for dispatcher-bus contacts, in addition to group calls.
Dave
Dave
Hamilton Street railway has done the same thing too, both with their old Moto and their new DMR system.
It is through their buses "Ranger" GPS/Driver console.
It is through their buses "Ranger" GPS/Driver console.
No, they aren't trunked. London Transit is analog conventional. I know on the channel they use for overtime, I often hear what sounds like morse code at the beginning of calls. don't know what that is about
satboy8888
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No, they are not on the trunked p25 system at all.
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Muxlow
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LTC has a UHF TRBO repeater for the inspectors and mechanics, Analog for the dispatch-to-bus operations. When they get a call their hand set in the bus rings.. sooo my guess would be it comves over the onboard computer system either via wifi or cell
The reason I'm kinda confused about how it works, is the one day I was riding on one of the buses, listening to the LTC on my Baofeng UV-5R, and LTC dispatch called bus 457 to ask about a passenger who left a cellphone on the bus. The bus I was riding on was bus 315, and it's radio didn't go off. From what I know, (and I could be completely wrong) SelCall really only works on a digital system, and LTC is on an analog system, so I'm trying to figure out how they are doing it. Could they be using CTCSS codes? and if so, with the size of their fleet, how are they able to get a unique code for each separate vehicle?
DaveH
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You're right CTCSS would not likely be practical. At the beginning of transmissions do you hear a burst of tones, MDC-1200 or other? Maybe DCS, more codes, but there are better ways to do this.
What frequency is this (do not see anything listed)?
Dave
They are on 410.1625 for the main frequency, input is on 415.1625
On the DB, they do appear to have a PL of 146.2
in answer to your first question, no, I've never heard any tones at the beginning of a transmission. I don't know a lot about analog systems, but is it possible they are able to control it using some sort of radio data protocol?
DaveH
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OK, seeing the listing now, just not looking in the right place.
Not an expert on selective calling, just thinking it must be sub-audible.
Dave
Not an expert on selective calling, just thinking it must be sub-audible.
Dave
mapleradio
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Their "Ranger" touchpanels have software that controls the radios. Similar to other municipalities such as Hamilton.
but isn't HSR using DMR tier 3? and as far as LTC goes, I know some of their buses are using the MDT's by Trapeze, but the majority of them are still using the MDT that looks like this
not sure if that's the exact MDT model they use, but its the closest i could find
I believe Burlington Transit uses "Rangers" also, but not sure if it controls the P25 radios have not been on a BT bus in a long while.
https://youtu.be/We7sXMAHEAo?t=387 you can see the unit HSR uses in this video.
https://youtu.be/We7sXMAHEAo?t=387 you can see the unit HSR uses in this video.
yeah, LTC doesn't have any MDT's like that
mapleradio
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Sorry,
I use 'Ranger' in place of MDT.
A long-term driver when I was in the area told me that's how the system selects the callee was via the MDT and a Radio Interface.
I use 'Ranger' in place of MDT.
A long-term driver when I was in the area told me that's how the system selects the callee was via the MDT and a Radio Interface.
Ohhh, so maybe what happens is when LTC base wants to call an operator, they send a data message to the MDT, which triggers their handset to ring, which in turn is connected to the radio interface. that could be why you never hear any tones for it, because the triggering action is done over a cellular data system.
Only other thing I can't figure out, is on the overtime channel for LTC, or what the DB calls the "Control" channel, quite often before a transmission from the dispatcher, theres a short burst of what sounds like morse code. anyone got any ideas of what that might be?
Mississauga Transit had a similar system although trunked. The bus radios sat on one talkgroup and a data burst would send the bus to the voice talkgroup. When the call was finished the bus would return back to the other talkgroup.
If a fleet call was made, you could watch all the buses affiliate with the voice talkgroup and after the call, they would affiliate back.
There was one talkgroup that the supervisors used dtmf on that would tell the bus radio to go to the voice talkgroup. I assume the supervisor manually switched to the voice channel.
If you find a conventional channel with data, see if you can correlate the voice calls with the data.
If a fleet call was made, you could watch all the buses affiliate with the voice talkgroup and after the call, they would affiliate back.
There was one talkgroup that the supervisors used dtmf on that would tell the bus radio to go to the voice talkgroup. I assume the supervisor manually switched to the voice channel.
If you find a conventional channel with data, see if you can correlate the voice calls with the data.
that is certainly something to try. Maybe their MDT's aren't actually on the cellular band. one other thought I had was that for that specific function, they could possibly use their DMR frequency if only to trigger the buses handset. guess I'm gonna have a few new ideas to try out. Thank goodness I got my 2 SDR sticks
radioman2001
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I agree with Mike, there used to be a M system that used a similar to trunking data channel that the bus radio parked on waiting for calls and also provided data from the bus back to dispatch (coin box alarm, bus location, emergency button, etc). Don't know if it is this system,but that what M made years ago for Transit operators.
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