Does the BCI require STEREO transmission?

[021]

Take a look at:
http://www.fm-transmitter.com/technical/what-transmitter-do-i-need.htm
(about mono transmission it states: ". ...This is best used where there will be little music involved in the transmission. However, broadcasting in mono is not usually an option for radio stations subject to license terms. "

So does the BCI require stations to broadcast with FM stereo??
With stations with mostly speech broadcasts FM mono transmisison would usually be a better option as there would be better S/N ratio (even to an extent on mono receivers or stereo recevers switched to mono) and less multipath distortion in hilly/built up areas

http://www.fm-transmitter.com also states about mono transmission "the sound will not be as good as stereo. "
It would be more correct to say that (with mono) there would be no stereo seperation (having different audio on L and R) if the audio source is stereo.
It might be an urban myth but there is absolutey no difference in audio bandwidth (i.e. up to 15kHz) with a mono or stereo transmission.

[Mike]

Mono also takes up less bandwidth and for smaller community stations (without mountain sites) it would actuually make a lot of sense as multipath effects ould be less noticable.

Theres cetainly little point in a station like Newstalk being in Stereo (or even on FM but thats another story)

What is the situation with RDS though ? Some community stations arent bothering with it. With the majority of pirates now using it surely all Legal operators should be using it Otrherwise the public are likely to become confused over which stations are actually pirates

[021]

For single frequency stations there is less advantage to having RDS than with multiple frequency stations. RDS is not without its disadvantages - RDS can cause a 'whirring' type sound to break through on the audio in areas suffering from multipath problems especially if there is also stereo. Some pirates (and possibly some legal stations) with RDS make the mistake of having the RDS subcarrier set too high which greatly increases this problem

The community stations (unlike say FM104 in Dublin) usually very heavily promote their exact frequency so people aren't going to be any less confused tuning them in if there is RDS there or not.

[Mike]

What about the new AM stations. Will any of these try stereo I wonder ?

http://ourworld.compuserve.com/homepages/kevtronics/
http://users.hfx.eastlink.ca/~amstereo/
http://www.stereoam.com/

[021]

Mike, your joking? hardly worthwhile for the new AM stations to use AM stereo, there being no AM stereo receivers available. In the US where AM stereo was introduced, it is mostly abandonded due to most AM stations going talk formats.

Its worth mentioning that a lot of the general public do not even understand what stereo is!
If people are remarking about MW/LW not being "stereo", its usually the lack of upper audio bandwidth (treble) they are complaining about, rather than the lack of seperate L and R channels!

I do not think the BCI should require smaller FM stations (or even large stations serving hilly areas) to broadcast stereo (and I doubt this is the case anyway, unlike what the owner of that website implies), but what the BCI should do is require cable TV companies to include the NICAM stereo of at least our national TV stations, because there are certain cable companies not doing so in some towns/cities!

Would also agree it is questionable whether Newstalk should be FM stereo, despite it having a most powerful mountain FM signal in Dublin. I presume it is only has stereo during some ads/intro music?

BTW
With the discussion on audio quality some FM mono broadcasters make the following mistakes which do cause needless inferior audio for themselves:

(a) have no pre-emphasis
(b) Do not combine Left and Right into the one channel, with only L OR R being broadcast! With the result some components of the music is missing! (Even RTE made this mistake in the past on a MW transmitter)

[Mike]

Atlantic 252 suffered this problem for a long time as well.
Other stereo problems Ive come across on both pirates and legal stations include.
reversal of L/R channels
One channel being much louder than the other
One (L or R) channel being broadcast over BOTH channels of a stereo transmission
Transmission being in mono (despite being announced as stereo and pilot tone being present)
And of course the old favorite phasing trick (although when it happens its USUALLY sorted pretty quickly)

[Mike]

RE: The TV channels on Cable 021 has a very good point. Theres little excuse in this day and age for cable operators not carrying ALL channels in Stereo especially given the ridiculous amounts of money they charge.
Also surely the "community text pages" that many operators carry ought to be made available as a teletext service. Do they really expect people to sit through 15 minutes of rolling pages for the info that they want

[TonyCurrie]

Some years ago I was put in charge of a new station in England. We were given a maximum 100 watts to serve quite a large area, and I proposed that we broadcast in mono, for all the reasons already discussed.

The board had a canary. "You can't transmit in mono in this day and age....etc etc etc". The fact that not a single member of the board would have known whether the station was in mono or stereo without looking at the "stereo" display on the receiver was neither here nor there. Stereo was - is - perceived as "modern" and mono is seen as "old-fashioned", with most people wrongly likening the differences to colour/ monochrome TV.

In fact, I reckon that only those listening on headphones will ever have any spatial awareness. The majority of cheap portable stereo radio/cassette/CD players have the speakers so close together that you'd really have to sit about four inches from the unit to hear any stereo.

So I'd be in favour of mono for stations that have a power/coverage problem.

I'd also like to see a little education for some of the so-called engineers who manage to achieve some of the dismal effects referred to above - the most common certainly being one stereo leg being fed to either a mono or worse a stereo channel, which is widespread these days.

Rant over!

[Justin Speck]

I have a vague recollection that, rather a long time ago now, BBC Radio 4 used to switch between mono and stereo depending on programme content. The idea was that if you weren't doing a stereo programme you could improve the S/N for the listeners. A laudable idea.

I suspect this meant that some people could receive it at some times but not at all at others. People are generally happy until you tell them that they're missing out on something hence constant stereo (or rather mono + pilot tone) was introduced.

Do you remember when BBC R1 introduced its first FM transmitter at CP? They had jingles (going out on MW as well) saying something like Radio 1 in stereo ain't we great, you know the sort of thing. The number of folk I spoke to who swore that Radio 1 was definitely in stereo when I knew they were only listening to MW was amazing. It must be true - they said so on the radio!:)

[TonyCurrie]

In the early days of Radio Clyde we switched between mono and stereo as well. There was a switch on the desk that sent a high frequency tone to the transmitter to change the pilot tone status.

Unfortunately it would quite often switch the pilot off and then fail miserably to switch it on again (rather like my central heating boiler).

So the edict came out ... leave it alone!!!!

:)