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#191008 - 12/15/09 06:36 AM Digital Radio?  
Trumpy  Offline

Joined: Jul 2002
Posts: 8,217
SI,New Zealand
Apparently, most of the analouge FM broadcast licences that radio stations use over here are due to expire in 2011.
Now, a lot of the stations involved, are not wanting to commit to a licence that lasts 20 years in it's current format, given that Digital radio will be introduced here within that time-frame.

They haven't even decided on a particular format yet. crazy

OK, with Digital TV you can just get a set-top box, that is all well and good, there is often room for one of them under your TV set.

With Digital radio, does this mean that any FM radio's we have in our cars are pretty much useless?
I mean, is there some sort of a "converter" that can be installed in line with the aerial to recieve these digital signals with an analouge radio?

This is the first I've heard of the licences running out, no doubt (as always) we'll end up using a system that is different to everyone else in the world and it will be forced upon us at the last minute, because some didn't do thier home-work.

Your thoughts?

Let's face it, these days if you're not young, you're old - Red Green grin

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#191011 - 12/15/09 08:58 AM Re: Digital Radio? [Re: Trumpy]  
aussie240  Offline
Joined: Jul 2005
Posts: 223
Blue Mountains, NSW, Australia
The situation in the UK where DAB has been in use for some time appears to be dire as far as analog FM stations go. Latest policy was that all but low power FM (I presume that means like our local community type stations)will be shut down fairly soon. Reports seem to indicate general dissatisfaction with the DAB quality. Hardly surprising with the all or nothing digital signal and when the bit rate is 'economised' to allow more channels on the one carrier.
Here in Australia, DAB has officially been in operation for about 6 months. Our version is DAB+ and not the same as the UK. (Here we go with incompatibility).Like digital TV, there's no general consumer interest; it's still in the geek/nerd toy stage. There is at this stage no plan to turn off any analog radio "for many years to come".
Given the distances between population centres in Australia, medium wave AM is still highly regarded in rural areas because it travels whereas VHF FM is dependent on topography. Given DAB is up in Band 3 (roughly 200MHz) I would expect even shorter distances than FM. And, of course unlike AM or FM where the reception just gets noisier (but still useable) with a weakening signal, DAB leaves you with nothing under the same circumstances. So, I think analog is likely to survive in rural areas after it is eventually shut down in the cities.
One serious threat to AM stations though, is Sydney where most of the transmitters are in what is now highly sought after area for development (i.e. ugly blocks of Soviet style flats). Given nothing can be built within about 250m of the towers in case they collapse, there is pressure to move them. One could be cynical and see this as an excuse to shut them down altogether.
Also, consider the changing demographic of listeners. We now have a generation that don't listen to AM and once the baby boomer generation has gone AM is sure to go with it. Generation Y while it grew up after FM was introduced here is making the switch to mp3 players and internet downloads, so I don't think they'll miss it too much. How often do you see a Gen Y or younger person with a portable radio now?
As for receiving DAB on existing radios, that's an important issue as I collect and restore ancient valve radios. The only way to do it is simply feed the audio output of a DAB receiver into an AM or FM modulator. But while an extra box is tolerable with digital TV, it would be a complete pain with portable sets. The tuning in of stations would still have to be done on the DAB receiver. Whichever way you look at it, the charm of tuning in stations with a variable condenser in your old valve radio will be gone.

#191014 - 12/15/09 02:32 PM Re: Digital Radio? [Re: aussie240]  
gfretwell  Offline

Joined: Jul 2004
Posts: 9,099
I haven't heard much about it in the US although I am sure there are a lot of people on the left that would like to shut down AM radio because the perception is that it is dominated by right wing talk shows.
The government is still bruised by the digital TV conversion so I doubt they are ready for another 10 year fight right now. Mike is right, this will make all current radios obsolete and I doubt there is any easy "converter" that will do anything but decode the signal and retransmit it on FM. At that point it is probably cheaper to replace the radio.
Personally I bet radio would just go away for most people.
I seldom listen to mine. I like MP3 players for my music.

Greg Fretwell

#191029 - 12/15/09 09:00 PM Re: Digital Radio? [Re: gfretwell]  
sparky  Offline
Joined: Oct 2000
Posts: 5,311
the entire concept of digital is to get all those freeloading antenea people out of the picture

h*ll, you gotta $$$ to watch anything decent on tv now, so why is this a big surprise?


#191036 - 12/16/09 01:15 PM Re: Digital Radio? [Re: sparky]  
Joined: Mar 2004
Posts: 251
Kingwood, TX USA
There currently many radio stations in the US broadcasting both analog and digitally now, mostly in larger cities. The digital broadcast are clearer. There is no fade, multipath, or noise on digital. Digital still has limitations as to distance and penetration, mostly due to lower power levels. The main advantage of digital is bandwidth. Like with digital TV, you can have a lot more audio streams in the same space as one analog broadcast. You can also stream text at the same time. Most digital receivers display the song played, and sometime traffic data at the same time. One reason the TV and radio stations like to switch to digital is to compete with all the paid services, like cable and satellite TV and radio. Broadcast (Free) TV and radio stations can now have several channels in the same spectrum that their old analog station occupied. More channels mean more chances to sell advertising.

#192255 - 02/03/10 09:08 AM Re: Digital Radio? [Re: WESTUPLACE]  
Trumpy  Offline

Joined: Jul 2002
Posts: 8,217
SI,New Zealand
You just jogged my memory.
I read about digital radio in cars, back in 1989, in a copy of Electronics Today International (a now defunct Australian hobbyists magazine).
The article was explaining about how the new German radios being installed into cars at the time would have traffic reports and the like beamed across the screen of your radio/CD player.

Let's face it, these days if you're not young, you're old - Red Green grin

#192279 - 02/05/10 12:39 AM Re: Digital Radio? [Re: Trumpy]  
Joined: Mar 2004
Posts: 251
Kingwood, TX USA
Years ago, pay music services used FM broadcast subcarriers to deliver there service. Those with some electronic savvy could build decoders. Wala, a receiver that picked up elevator music. Those same subcarriers were later used ( and still are in a few locales) for Taping for the Blind. Books and newspapers were read for blind people. Most of the larger AM stations here in Houston TX have digital broadcast. The digital broadcast are on the FM bands. Low band freq. do not work well with digital broadcasting. I still like to get on the 75 meter AM Ham band. I still like the tone of talking with someone on AM.

#192445 - 02/14/10 08:42 AM Re: Digital Radio? [Re: WESTUPLACE]  
djk  Offline
Joined: Dec 2002
Posts: 1,237
DAB is really a solution in search of a problem rather than something that is an attractive replacement for FM radio.

It offers practically no advantages to end users and adds a whole lot of problems, costs and unnecessary complications.

Here in Ireland, DAB services were launched by the national public service broadcaster, RTE, but no commercial stations have shown any interest in the project and in general won't touch it with a barge poll. They prefer to retain their existing FM infrastructure.

Advantages of DAB:
1) Single frequency network vs FM's different frequencies in different areas.
2) Electronic programme guides / live text information.
3) More stations into the same amount of spectrum as FM

NB: Many of these advantages are provided by analogue FM services using the RDS (Radio Data System). This allows car radios to automatically tune to the strongest transmitter on national/multi-transmitter local FM services, provides programme information text, traffic reports services etc etc.

Disadvantages of DAB:
1) Complex and expensive broadcast system
2) Requirement for stations to share a multiplexes rather than have their own FM transmitters. This leads to issues with creating a telco-like monopoly to manage broadcasting.
3) Complicated reception equipment which is often bulkier, more expensive and much more power hungry than a simple FM receiver.
4) Poor audio quality is often experienced due to over-compression of signals or poor signal quality. Instead of a slight hiss like FM, this causes a 'bubbling mud' sound.
5) Lack of availability of receivers. Because DAB is so unpopular there hasn't really been a huge interest from manufacturers in creating equipment. So, it's still rather niche and specialist.
6) Lack of integrated receivers e.g. in mobile phones, mp3 players etc.

Commercialisation problems:

1) Lack of control and independence of infrastructure - local and national stations in Ireland at present own their own FM networks. They may share broadcasting sites, but they are entirely independent and don't have to rely on an infrastructure provider.
2) Local stations don't like the idea that other larger local stations might suddenly become available nationally.
3) Large-scale investment required to change broadcasting infrastructure and advertise new services.
4) Very small community stations and rural commercial FM stations might be wiped out if they had to re-invest in duplicating their FM broadcast networks.
5) Risk of losing customers who know the station by its dial-position. Many Irish stations call themselves by their FM frequency e.g. Dublin's 98, 104fm, Midlands 103, Cork's 96fm, Cork's RedFM 104-106, Newstalk 106-108 etc etc
6) Poor choice of receivers.
7) All of the indications so far are that consumers don't seem to warm to DAB and adoption rates are very poor, even in markets where the Public Service Broadcaster has really pushed it e.g. the BBC in the UK.

So, overall, I think DAB is just digital dogma i.e. digital for the sake of digital. Unlike Digital TV, it doesn't really offer consumers with something better, easier to use with more choice.

I would see some sense in using FM subcarriers to allow stations to broadcast extra digital services.

DRM ( Digital Radio Mondiale Digital Radio Mondial ) is also showing good prospects of use on AM (Medium Wave and Longwave). This could provide near-FM quality and stereo on AM services which cover large areas / are used for international broadcasts.

Last edited by djk; 02/14/10 08:49 AM.

#192462 - 02/15/10 02:01 AM Re: Digital Radio? [Re: djk]  
Joined: Mar 2004
Posts: 251
Kingwood, TX USA
With very few exceptions, all digital broadcasting is done on commercial (non government)stations here in the states. It is done voluntarily by the stations. There is no current requirement that they have any digital broadcast. Many of the newer receivers are able to pick up the digital broadcast, but there is no requirement that all receivers be equipped with digital receivers. I have a digital receiver and sound is great (CD quality) but reception is not as wide spread as the analog signal. The receiver will automatically switch to analog at the loss of the digital signal. On a side note, at one of the transmitter sites here, 7 FM stations share 1 antenna for there analog broadcast. A very large combiner connects all 7 transmitters to the single antenna.

#192478 - 02/15/10 09:08 PM Re: Digital Radio? [Re: WESTUPLACE]  
Trumpy  Offline

Joined: Jul 2002
Posts: 8,217
SI,New Zealand
I am assuming you are describing a car radio that recieves a digital/analouge signal?
If so, what brand is it, as I'm not aware of any manufacturers that make them for the auto market.

Let's face it, this is going to be a HUGE market once governments decide that FM analouge has had it's day.

Someone mentioned AM Stereo above, I do know that Australia introduced this in 1985, using the Motorola C-QUAM system, however I'm not sure that it really took off that well, maybe Aussie240 can enlighten us?

I'm not even sure how AM Stereo would sound, given that all of the AM signals I've ever heard on the broadcast band have been mono-aural and it lacks any top-end, regardless of any signal conditioning you do to it (as in treble and midrange cut/boost).

Let's face it, these days if you're not young, you're old - Red Green grin

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