DAB Trial

zap

This DAB trial RTE are doing in dub/louth can they put any station they want on the mux i.e. can someone set up a station and pay RTE NL to broadcast it or doe sit require a BCI license?

flogen

I seems to me that companies will require a licence once the DAB system becomes fully operational, but at the moment the operators are free to do what they want (operators being RTÉ and the rest of Digital Radio Ireland).

I think RTÉ's new stations aren't BCI licences and nor will the other stations that come on during the trial.

zap

how does it work is an audio signal simply fed in an ADC conveter and fed out over the TX network

L1011

zap wrote:

how does it work is an audio signal simply fed in an ADC conveter and fed out over the TX network

That or a digital feed is sent to a central location, where they're multiplexed. Then the TX network has to handle error correction, synchronisation, etc.

zilog_jones

Are they using Band III like in the UK?

L1011

Yes, they are. Blocks 12C (national) and 12A (dublin)

Ulsterman 1690

is an audio signal simply fed in an ADC conveter

Bit more to it than that

The digital audio needs to undergo data reduction (lossy compression) then all manner of error correction, coding and syncronisation along with all the data to specify where the audio stream is located in a multiplex (PID's) and what data rate is used plus all the data to support station identificaton and Radiotext

Finally if more than one transmitter is being used they need to be synchronised using GPS

watty

So if the USA blocks GPS for "war on Terror" reasons then a lot of DTT and DAB stops working?

Ulsterman 1690

They probably (hopefully :eek: ) have alternative means of timing/syncronisation of the SFN in the event of GPS failing or being degraded/encrypted.

Indeed some people reckon that the only reason we have DTT is that some governments were concerned that over dependence on satellite could make the country vunerable in wartime.

Although the Hotbird satellite should be safe enough given that just about every country with any degree of military capability uses it

It is scary though the amount of technology/infrastructure that relies on GPS (especially with the 15.8 KHz "GBR Rugby" transmitter being phased out) I remember hearing somewhere that the EU were considering developing their own system for this reason.

watty

Galilleo

zilog_jones

Ulsterman 1690 wrote:

especially with the 15.8 KHz "GBR Rugby" transmitter being phased out

http://en.wikipedia.org/wiki/Time_from_NPL
According to that it's only just been relocated last month - is it really being phased out? I like my radio controlled clock - best £8 I ever spent

watty

The time is on 60KHz. It's moved not phased out.