Keolis dispatcher DTMF tone.

[Skyman2002]

Hello there! Back in November of 2020, when listening to the Keolis Worcester Main Line, I heard a DTMF number tone generated at the end of every transmission from the dispatcher.

Can someone please explain the reason behind this tone? When onboard the trains, i hear the dispatcher on the conductors radio, but no tone. It's only heard on my scanner.

Thank you!

 

[kb1kvd]

That was done for identification of various base sites from the field. What we did was assign each base site a number that is transmitted at the end of each transmission. It also to acts as a roger beep on the base sites. One of the problems that was brought up to us was that the train crews couldn’t tell when the dispatcher was done talking. Some of the dispatchers tend to make long pauses during form d read backs, and this was causing train crews to step on the dispatcher thus causing them not to hear the rest of the information.

 

[HudsonScannerGuy]

I always heard DTMF when the trains were at Framingham going to Boston and they needed to activate the crossing...

 

[kb1kvd]

The DTMF the op is referring to is only on the base radios. It is only transmitted on dekey by the dispatcher. The DTMF that is often heard in the Framingham area is used for activating the crossings on inbound movements. We also use that setup for crossings in a few locations such as Needham, Stoughton, North Scituate, South Hampton Yard and the drawbridges on the East Route.

 

[Skyman2002]

That was done for identification of various base sites from the field. What we did was assign each base site a number that is transmitted at the end of each transmission. It also to acts as a roger beep on the base sites. One of the problems that was brought up to us was that the train crews couldn’t tell when the dispatcher was done talking. Some of the dispatchers tend to make long pauses during form d read backs, and this was causing train crews to step on the dispatcher thus causing them not to hear the rest of the information.

Thank you for this info!

Super helpful!

-Sky

 

[Skyman2002]

That was done for identification of various base sites from the field. What we did was assign each base site a number that is transmitted at the end of each transmission. It also to acts as a roger beep on the base sites. One of the problems that was brought up to us was that the train crews couldn’t tell when the dispatcher was done talking. Some of the dispatchers tend to make long pauses during form d read backs, and this was causing train crews to step on the dispatcher thus causing them not to hear the rest of the information.

On the discussion of Base stations, are the Various stations like Framingham or Worcester on tall towers? Or are they small antennas on a telephone pole?

I know on the P&W, they use a Yagi antenna on a telephone pole with about 35 watts of power.

 

[kb1kvd]

Our base sites are a mix of tall towers and telephone pole mounted antennas, most of our sites are just telephone pole mounted up around 40-60 ft depending on location. We use 4 bay dipole verticals on most sites and were running about 50 watts forward. We've gotten rid of the yagi's for any of the voice work in our system and moved over to the 4 bay dipoles, but we do still have yagi's in operation as crossing recorder radios and other non vital systems.

 

[Skyman2002]

Our base sites are a mix of tall towers and telephone pole mounted antennas, most of our sites are just telephone pole mounted up around 40-60 ft depending on location. We use 4 bay dipole verticals on most sites and were running about 50 watts forward. We've gotten rid of the yagi's for any of the voice work in our system and moved over to the 4 bay dipoles, but we do still have yagi's in operation as crossing recorder radios and other non vital systems.

It's always fascinating to hear of the different types of transmitters that get installed to get the job done. Thanks!

I used to hear a Defect detector in the Ashland area, but I haven't picked it up in the last year or so.

 

[kb1kvd]

The detector has been offline for about a year due to equipment issues and the lack of parts. The radio side is just an Icom F5061D running into a quarter wave antenna but the actual detector is made by progress rail and it has some issue with the track equipment.