AM Radio Train Station Broadcasts

BostonUrbEx wrote:I thought that project died a while ago?

It has the MassDOT, so it has to be recent.

Found the thread, and merged them. Looks like this is only about a year old.

Very low power broadcasts, only go a short distance, but anyone is allowed to transmit on that area, like the Talking House transmitters, you can put one in your house so people can hear your ad when they drive down the road.
http://www.talkinghouse.com/

Very low power, and very small antenna, all regulated by the FCC
http://www.fcc.gov/mb/audio/lowpwr.html

I can assure you, the station AM radio project is alive, well, and for now, rolled out. The radio brodcasts a voice synthesis of the text playing on the sign. Few stations have signs visible from the parking area.

Some stations were passed over because of parking lot size and other considerations. The low power radios use the 1630 AM frequency in all instances except when interference was encountered. A list of the stations and frequencies is at http://mbcr.net/radio_station_list.pdf

frank754 wrote:Very low power broadcasts, only go a short distance, but anyone is allowed to transmit on that area, like the Talking House transmitters, you can put one in your house so people can hear your ad when they drive down the road.
http://www.talkinghouse.com/

Very low power, and very small antenna, all regulated by the FCC
http://www.fcc.gov/mb/audio/lowpwr.html

For the T's radio they wouldn't use regular antennas like some guy broadcasting off the top of a building, or some of those "Tune in for traffic and tourist Info" automated stations you see on some interstates. In tunnel and station infrastructure they'd use carrier currents, which is basically using wiring as the antenna to pass the signal through enclosed spaces. Bunch of colleges in the area do this at their dorms with transmitter cables inside the building. Allows the students to listen in their rooms, but it's only good for a couple buildings' radius because the signals have to pass through brick, steel beams, etc. I remember being pissed off that BU's carrier currents were always broken and so slow to get repaired that it was impossible to hear WTBU hardly anywhere on campus (that big radio tower on the top of the COM building is vacant...their student station's all carrier current or--now--online streaming). Not exactly a state-of-the-art system, either...decrepit 1950's cabling from decrepit 1950's transmitters. You could probably wire one of these up in your basement from a spool of cheap cable and $50 of mail-order doodads from an electronic components catalog...some assembly required.

This is the kind of system the T would do because it's so freaking easy to string a wire segment in a tunnel or around a station. I'm sure they're doing this because the technology--such that it is--is pretty damn close to free and the installation costs can probably be underwritten by some obscure public service grant elegibility.

frank754 wrote:Very low power broadcasts, only go a short distance, but anyone is allowed to transmit on that area, like the Talking House transmitters, you can put one in your house so people can hear your ad when they drive down the road.
http://www.talkinghouse.com/

Very low power, and very small antenna, all regulated by the FCC
http://www.fcc.gov/mb/audio/lowpwr.html

That's exactly how it was done........

F-line to Dudley via Park wrote:(that big radio tower on the top of the COM building is vacant..

Its actually (unfortunately) gone now. They took it down a year or two ago, there was an entry on Universal Hub about it. The building looks purposeless now without it

Are these broadcasts still being made? I was taking photos at Melrose Cedar Park today, and when I was standing next to the hut that houses the controls for the station's countdown signs I could hear a digitized voice coming from inside every so often. I noted that it was transcribing the announcements being shown on the signs.

MBTA3247 wrote:Are these broadcasts still being made? I was taking photos at Melrose Cedar Park today, and when I was standing next to the hut that houses the controls for the station's countdown signs I could hear a digitized voice coming from inside every so often. I noted that it was transcribing the announcements being shown on the signs.

It works fine at Anderson/Woburn.

Yes the broadcast are still being made. The voice you're hearing is the speaker on the radio itself as the text to speech board reads off the data coming from the network.

Carrier current AM broadcasting, per se, can use and historically has used existing wiring for the broadcast antenna. In the case of the T, 600 volt traction power feeders as well as ordinary AC lighting lines can be used.

Problems arise with interference, notably from other passengers' phones and game consoles, train electrical circuits including for propulsion, fluorescent lights, and the digital countdown signs, all of which, emit various "RFI" (radio frequency interference). Most likely it would not be possible to receive the AM broadcasts inside a train even with separate broadcasting antenna wires strung in the tunnel or along the tracks.