west5alpha
Member
- Joined
- Dec 7, 2009
- Messages
- 157
I hear the dispatcher on my analog scanner but not the replies from the bus drivers the drivers on a different radio.
I hear Access-a-bus no problems.
I hear Access-a-bus no problems.
Transit Buses HRM
- Thread starter west5alpha
- Start date
- Status
So the system for the buses is not a standard repeater system where you monitor just the one frequency; it's sort of a duplex/simplex kinda system (not sure what it would be called) where there's actually two frequencies per channel, with the base radio (communications centre) transmitting on the lower frequency, and the bus radio transmitting on the higher. A lot of taxis used to operate on a similar system.
For example in the database, channel pairs 2 and 3 are the ones you'll hear most of the conversations on. For channel #2, the comms centre transmits on 411.0375 and the bus responds on 416.0375. So in order to hear both sides of a conversation on that channel, you need both of the frequencies programmed. It also helps in your scanner if you can disable the delay mode (where it hangs on a frequency for 2 seconds after the transmission ends), otherwise you miss 2 seconds of the reply on the other frequency. Also keep in mind that it is still very much simplex, so depending on where you are and where the bus is, you may not always hear the bus side.
Access-a-bus on the other hand uses a standard repeater system, so you only need to monitor the one frequency (410.1625)
For anyone who cares, the buses all have mobile data terminals (MDTs) which helps keep the operators on schedule and on route, and also controls the radio system; they can't just pick up the mic and start transmitting, they have to hit the RTT (request to talk) button on the MDT, which puts them in a queue; when the comms centre answers, the system uses one of the two available channel pairs for the conversation.
Channel #1 in the database (410.1125 & 415.1125) was historically known as the "fall-back channel" and was the one the radios all revert to when the MDTs go down, and in those situations it was basically a free for all, with operators transmitting all over each other. Thankfully the system doesn't seem to go down very often anymore.
That channel was also the one that the comms centre sent fleet-wide broadcasts over, but the new MDT system they started using a few years ago supports text messaging, so pretty much all of those broadcasts (things like detours for example) go out to the operators via text.
For example in the database, channel pairs 2 and 3 are the ones you'll hear most of the conversations on. For channel #2, the comms centre transmits on 411.0375 and the bus responds on 416.0375. So in order to hear both sides of a conversation on that channel, you need both of the frequencies programmed. It also helps in your scanner if you can disable the delay mode (where it hangs on a frequency for 2 seconds after the transmission ends), otherwise you miss 2 seconds of the reply on the other frequency. Also keep in mind that it is still very much simplex, so depending on where you are and where the bus is, you may not always hear the bus side.
Access-a-bus on the other hand uses a standard repeater system, so you only need to monitor the one frequency (410.1625)
For anyone who cares, the buses all have mobile data terminals (MDTs) which helps keep the operators on schedule and on route, and also controls the radio system; they can't just pick up the mic and start transmitting, they have to hit the RTT (request to talk) button on the MDT, which puts them in a queue; when the comms centre answers, the system uses one of the two available channel pairs for the conversation.
Channel #1 in the database (410.1125 & 415.1125) was historically known as the "fall-back channel" and was the one the radios all revert to when the MDTs go down, and in those situations it was basically a free for all, with operators transmitting all over each other. Thankfully the system doesn't seem to go down very often anymore.
That channel was also the one that the comms centre sent fleet-wide broadcasts over, but the new MDT system they started using a few years ago supports text messaging, so pretty much all of those broadcasts (things like detours for example) go out to the operators via text.
- Status
Similar threads
