emeregency radio broadcast interruption

londonTiger

Had a really strange experience twice. Both times while driving hrough tunnels.

CD turned off and turned to radio with the station title ALARM! I heard some gibberish come from the outside saying "emergency test announcement" or something along those lines. The radio was meant to echo this as well but it wasn't very clear.

Is this a thing? Do cars radios have a public service channel which it detects and automatically tunes into?

dacouch

I'm guessing this was in the Limehouse Link.

The emergency services have the ability to interrupt your radio to broadcast emergency messages.

The most common one used in the LL is that there is an obstruction in one of the lanes ahead

force_ten

sound like an RDS broadcast

most radios now have A Radio Data System which is used as a Traffic Message Channel, while you are listening to radio 1 the local radio broadcasts a traffic message and the RDS plays the traffic message over the station of choice

I would say the tunnel operator has an RDS system to broadcast emergency messages to vehicles in the tunnel

DUTR

force_ten wrote: »

sound like an RDS broadcast

most radios now have A Radio Data System which is used as a Traffic Message Channel, while you are listening to radio 1 the local radio broadcasts a traffic message and the RDS plays the traffic message over the station of choice

I would say the tunnel operator has an RDS system to broadcast emergency messages to vehicles in the tunnel

Agreed there is the facility on RDS , never known it work though, but I guess it depends where the user is.

robbies_gal

happens to me in the limehouse link aswell never happened anywhere else

londonTiger

this was actually in blackwall tunnel.

s_b

are you sure its not your hearing aid;)

patman99

You can normally turn RDS off to prevent interruptions when listerning to CDs.

AdrianC

Probably TA set on - which'd put radio traffic announcements over any other audio source, too.

DUTR

AdrianC wrote: »

Probably TA set on - which'd put radio traffic announcements over any other audio source, too.

It's not the TA, it's the TMC which overides and listened to station, where as TA is only on the specific listened to station or EON shared station.

Rodders53

TMC is a data channel carried on Classic FM I think which is used to warn of traffic jams via sat nav units typically... not what is being described by the OP which involved audio via the car radio.

IIRC some tunnels in the UK have a 'leaky feeder' cable installed to carry the broadcast services (otherwise inside the tunnel you lose signal completely) and these have the ability for the tunnel operators to 'cut in' and override ALL services... which seems the OP heard a test of the facility (no point having it if it isn't tested).

http://www.landmobile.co.uk/news/londons-road-tunnels-radio-systems-what-lies-beneath

Rotherhithe and Limehouse seem to have this ... maybe Blackwall has been upgraded since the article?