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Old 24-12-2005, 01:15   #16
dk8cb
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Quote:
Originally posted by G8JQW
yes that's possible, but Sangean denied that the unit that Roberts Radio was evaluating was manufactured by them

At IFA in Berlin, Sangean were showing off the same DRM prototype receiver at their exhibition booth as could be seen at the DRM booth.

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Old 24-12-2005, 17:59   #17
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... and here is a picture taken at IFA Berlin showing the same type of receiver but labelled as Roberts
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Old 26-12-2005, 10:48   #18
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The model looks like, from the outside, the Sangean DPR1/Roberts Gemini 1 DAB set.

The Sangean Europe site, which I visited about a month ago, is not active though the link from the Sangean Taiwan site is still there.
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Old 02-01-2006, 00:38   #19
tacitus-ms
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No future for DRM because it reduces the coverage area

Now i have already been observing DRM for more than 1 1/2 years, but there is no progress any more. E.g. RTL on 1440 kHz seems to be a demonstration that on this frequency DRM does not work in mode B. In the evening when they use AM you can hear the station very clear and without any problems. But when they switch to DRM the very long IR causes a lot of dropouts. Of course, mode C or D could improve the situation, but only with an absolutely rediculous sound quality. Really unacceptable in the year 2006. DRM reduces the coverage area enormously. It seems, DRM was developed on the "green table".
Another good example: The station Deutschland Radio Kultur on LW 177 kHz. When they used the DRM mode the only way to receive was a magnetic loop. You had to null out the French interferer very precisely. Now they switched back to AM, and of course, you can hear a litte bit in the background if no music is played or nobody is talking, but it is amazing, how good the signal must be that a DRM receiver is able to decode the signal without dropouts. (Dream was a little bit better than DRM software when the interferer filter was activated)

I think DRM is just one error of a lot in the history of the technical development. Perhaps the developers should start from zero again to digitize the AM radio. Errare humanum est.

Last edited by tacitus-ms : 02-01-2006 at 00:53.
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Old 02-01-2006, 08:19   #20
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Re: No future for DRM because it reduces the coverage area

Quote:
Originally posted by tacitus-ms
Now i have already been observing DRM for more than 1 1/2 years, but there is no progress any more. E.g. RTL on 1440 kHz seems to be a demonstration that on this frequency DRM does not work in mode B. In the evening when they use AM you can hear the station very clear and without any problems. But when they switch to DRM the very long IR causes a lot of dropouts. Of course, mode C or D could improve the situation, but only with an absolutely rediculous sound quality. Really unacceptable in the year 2006. DRM reduces the coverage area enormously. It seems, DRM was developed on the "green table".
Another good example: The station Deutschland Radio Kultur on LW 177 kHz. When they used the DRM mode the only way to receive was a magnetic loop. You had to null out the French interferer very precisely. Now they switched back to AM, and of course, you can hear a litte bit in the background if no music is played or nobody is talking, but it is amazing, how good the signal must be that a DRM receiver is able to decode the signal without dropouts. (Dream was a little bit better than DRM software when the interferer filter was activated)

I think DRM is just one error of a lot in the history of the technical development. Perhaps the developers should start from zero again to digitize the AM radio. Errare humanum est.

Very well put, I think part of the problem is we all would like better quality on the AM Bands but apart from maybe local services DRM has too many faults, in my case to many dropouts, as I've said before jo public will not put up with it, I to have had DRM for 2 years or so and I don't see it going forward at all, also agree on the 1440 thing I could/can when in analogue get a good reception when it switches to DRM 95% of the time not worth listening to, well we will wait to see if improvements can be made which I'm not holding my breath on, or yes scap it and start again, oh and for RTL please close that hidious station that blures that once great Radio Luxembourg what a shambles that is, sorry.
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Old 02-01-2006, 10:09   #21
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I think DRM reception would work fine for local am stations and high powered national ones, I would love talksport and or Virgin in the UK to try DRM mode on AM at the same power levels to see what happens..

It's all looking very negative at the moment, hope DRM does'nt stay radio for anoraks for too mch longer but with the talk of DRM + perhaps everything is now going to be halted for a few years while we wait for a new spec and modules to be released etc ?

It seems ofcom are yet again holding things up with releasing freqs for testing in the UK. There's too many AM relays for BBC stations IMO which could be used for example. I would think barely anyone listens on AM now...
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Old 02-01-2006, 14:15   #22
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DRM as it stands now will probably work for stations on SW such as DW, BBC World Service and others as they give a clearer sound and are on several frequencies for a few hours each day but, for commercial broadcasters SW is no go as they need to be on 24/7 without the dropouts and I don't see that happening.

DRM+ sounds more interesting but again only for local stations and high powered nation stations as DRM Fan mentioned but no chance of that at present in the UK with lack of frequencies though this could be rectified but Ofcom don't seem to want to budge as usual, and this again as DRM Fan states could take years
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Old 02-01-2006, 19:00   #23
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A combination of 2 (1) action(s) could help to bring DRM to a success:

1) the broadcasters should adapt their bitrates better to conditions and circumstances on the AM-bands. Why do they run P-Stereo with the result of lower reliability and terrible artefacts? A little lower quality (if P-Stereo is an enhancement at all) is much better than drop outs and

2) a rework of the DRM-specification considering interference

or

extend the DRM-specification to allow a dual data stream. One with low audio quality but very robust - the second one transporting additional data necessary for high audio quality. The listener (or the receiver software) could decide what to prefere - quality and drop outs or stable with lower quality. If this would be implemented points 1) and 2) become outdated.

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Old 02-01-2006, 19:22   #24
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Quote:
Originally posted by df9rb
A combination of 2 (1) action(s) could help to bring DRM to a success:

1) the broadcasters should adapt their bitrates better to conditions and circumstances on the AM-bands. Why do they run P-Stereo with the result of lower reliability and terrible artefacts? A little lower quality (if P-Stereo is an enhancement at all) is much better than drop outs and

2) a rework of the DRM-specification considering interference

or

extend the DRM-specification to allow a dual data stream. One with low audio quality but very robust - the second one transporting additional data necessary for high audio quality. The listener (or the receiver software) could decide what to prefere - quality and drop outs or stable with lower quality. If this would be implemented points 1) and 2) become outdated.

Bernd, DF9RB

Agree with you Bernd, some people are expecting to much quality in the audio the higher the biterate the more chance of dropouts, if it means lower biterates and less dropouts that is what I would go for, it would still sound better in most cases than crackly old AM.
It is the chicken & egg syndrome also, no cheap but quality DRM radio's yet and no real decent radio stations yet, and most people in the UK are not that interested in BBC, DW, Radio Sweden etc, they have there place but the majority of the UK population are not interested.
The UK will end up with virtually what we have on DAB, Virgin, Talksport, Capital Gold etc, good for areas where FM/DAB is bad but to be fair these are quite isolated spots compared to the whole of the UK and I would expect these services to go onto DRM + anyway.
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Old 02-01-2006, 19:29   #25
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Quote:
Originally posted by df9rb
A combination of 2 (1) action(s) could help to bring DRM to a success:

1) the broadcasters should adapt their bitrates better to conditions and circumstances on the AM-bands. Why do they run P-Stereo with the result of lower reliability and terrible artefacts? A little lower quality (if P-Stereo is an enhancement at all) is much better than drop outs

Not too lower quality though ie bitrate on 3995 sounds awful worse than analogue SW why bother IMO. The main point of DRM is to provide better quality audio I thought and certainly stereo. Maybe the technology will never be perfect and if it is'nt broadcasters won't be interested. Another few years to wait I guess for DRM+ receivers that's IF even they ever materilize! They'll be probably yet another digital format by then :-(

It took about 8 years for DAB to get fairly established and that'a only in the UK and it's audio quality is constantly critisised on the radio forums etc

Even if we get the radios this year what is there too listen to anyway ? Full marks to radio Luxemburg but surely by now we should have say around half a dozen English stations to listen to also.

Manufaturing of DRM radios has made progress but not DRM radio STATIONS !
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Last edited by DRM-Fan : 02-01-2006 at 19:32.
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Old 02-01-2006, 19:37   #26
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The first thought I had when DRM started

Quote:
Originally posted by df9rb
....
extend the DRM-specification to allow a dual data stream. One with low audio quality but very robust - the second one transporting additional data necessary for high audio quality. The listener (or the receiver software) could decide what to prefere - quality and drop outs or stable with lower quality. If this would be implemented points 1) and 2) become outdated.

Bernd, DF9RB

Yes indeed! When I got my first contact with DRM, I was really surprised and astonished, that DRM DID NOT work that way. If I had been the project leader of it, dual stream or a equivalent solution would have been the first action point! UEP is not able to substitute this. I think, only a redisign of the specification and intensive FIELD TESTS can solve the problem.

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Old 02-01-2006, 19:48   #27
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Originally posted by DRM-Fan


Not too lower quality though ie bitrate on 3995 sounds awful worse than analogue SW why bother IMO. The main point of DRM is to provide better quality audio I thought and certainly stereo. Maybe the technology will never be perfect and if it is'nt broadcasters won't be interested. Another few years to wait I guess for DRM+ receivers that's IF even they ever materilize! They'll be probably yet another digital format by then :-(

It took about 8 years for DAB to get fairly established and that'a only in the UK and it's audio quality is constantly critisised on the radio forums etc

Even if we get the radios this year what is there too listen to anyway ? Full marks to radio Luxemburg but surely by now we should have say around half a dozen English stations to listen to also.

Manufaturing of DRM radios has made progress but not DRM radio STATIONS !

But that's part of the problem if people want stero AM broadcasts which most of us want they have to up the biterate but then you suffer dropouts which people will not put up with.

In 8 years DAB has only sold just over 1 million sets there are 60 million people in the UK that is still very tiny.

Yes full marks for RTL getting Luxembourg back on the air but have you noticed in the radio forums people say it's poor and that was within the first few months and it's hardly mentioned now, most people do not like it, they need to go back to the drawing board like DRM need to.
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Old 02-01-2006, 21:31   #28
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Quote:
Originally posted by DRM-Fan
The main point of DRM is to provide better quality audio I thought and certainly stereo.

I agree on the better quality aspect but I totally disagree on stereo. This may be (and we know it is) your personal preference (or should I say 'fetish' ) but I don't think that the general public would put such an emphasis on it.

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Old 02-01-2006, 22:11   #29
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I agree on the better quality aspect but I totally disagree on stereo. This may be (and we know it is) your personal preference (or should I say 'fetish' )

Fetish Roland ? steady on there!! I appreciate the best sound quality possible that's all and that has not been acheived anywhere in Europe on MW so yes I will admit DRM would give it a new lease of life but probably now not to be the case for sometime anyway

Quote:
but I don't think that the general public would put such an emphasis on it.

I'm not so sure I think a fair number would love as much stereo content as possible. Imagine listening to an ipod with mono headphones for example. Hearing DW on SW in stereo via the hi-fi is a novalty but I want this to become the norm not sure if it will now
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Old 03-01-2006, 08:15   #30
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Stereo is simply fabulous for radio, but all speech content has to be compatible with mono reception – so since we can't make full use of it, speech-based radio has largely stereo to the music channels: I don't think music is what will sell DRM, at least mainstream music. A lot of the DAB radios available are mono.

Mobile phones, Wi-Fi and even satellite are almost certain to cover the large market for music. On DRM, even before DRM+, music can be well catered for by local broadcasters on 26 MHz and the like.

It costs a lot of money to launch a radio service! Especially one where there won't be any listeners for a few months –_not too appealing to advertisers that! But in a Europe where wireless internet is available to a lot of people in urban areas, then DRM should provide other services. It can reduce the electricity and distribution costs for state broadcasters, but that's for the future (post analogue switch-off).

In the meantime, over-the-air radio needs news to keep its place among other technologies (as well as other general services, of course). But often governments need to have their arms twisted: why should they pay for news services?

I would like to think that as soon I had heard about that terrible ice rink collapse in Germany, I would have tuned to Deutsche Welle straight away to get all the latest news. But they aren't in a position to provide that sort of service.

I'm not criticising DW or any of the other international broadcasters : their budgets are stretched enough as it is. But perhaps the government-funded stations around Europe should look at how a commercial organisation, WRN, has made money out of the International Broadcasting business.

I also think DRM should be very attractive to broadcasters with local licences but who would like to go regional, thanks to overseas relays.

Obviously Radio Luxembourg is just ticking over until they really can get on air with a full commercial service.

I wonder is the consortium pushing DRM to non-members enough? It's a shame there aren't more progress reports on the official website.
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