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Old 16-09-2004, 22:12   #16
DRM-Fan
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Image and specs in attached pdf file...
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Old 17-09-2004, 13:20   #17
BofH
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18kz/20kz mode not supported!

This new receiver from Coding Technologies is a joke!

Last time I checked, the standard contained 18 kHz and 20 kHz "double bandwidth" modes which support a bitrate up to 72kbps.

However there appears to be no minimum requirement set by the DRM Consortium for a production DRM receiver to support these 18 kHz and 20 kHz modes!

The Mayah 2010 does contain these modes:
http://www.mayah.com/content/downloa.../DRM2010_e.pdf

However this new "Digital World Traveller" from Coding Technologies omits these important modes - and as this is supposedly the first high volume "production" consumer receiver, it is extremely worrying!

It seems to me we have another "AM Stereo" debacle on our hands, where lack of enforcement of certain minimum standards for receiver manufacturers (such as supporting decoding all DRM RF bandwidths) will lead to a situation whereby most consumer DRM radios will not support 18 kHz and 20 kHz because it is cheaper to make narrow banded radios!

Coding Technologies - it's not too late to recall the product and make it truly compatible with the DRM standard! Shame on you!

I certainly won't be buying a product that doesn't support all DRM transmission modes!

Last edited by BofH : 17-09-2004 at 13:44.
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Old 17-09-2004, 13:31   #18
Connor Walsh
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Well said BofH! You hit the nail on the head I think. Though 20KHz may require some changes from the ITU or HFCC?
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Old 17-09-2004, 13:40   #19
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Quote:
Originally posted by Connor Walsh
Well said BofH! You hit the nail on the head I think. Though 20KHz may require some changes from the ITU or HFCC?

In Europe most likely however other countries such as Canada and the US would be able to use the 20 kHz mode.

The 18 kHz mode is usable in much of the world, eg Australia and New Zealand amongst others have this channel width.

I'm not sure what the situation is with Shortwave channels however - it would be fairly easy to find two adjacent channels to allow use of 18 / 20 kHz bandwidth?

Last edited by BofH : 17-09-2004 at 13:45.
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Old 17-09-2004, 13:54   #20
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Hi

I noticed that the USB receiver does not support 18/20 kHz but it has the DRM logo on it. To use this logo it seems that a receiver does not have to conform to the DRM ETSI standard only that the company producing the receiver is a consortium member (or am I being a bit cynical?).


73s, Roger
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Old 17-09-2004, 15:10   #21
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Sorry, but I don't think that the lack of both wide modes is of any real significance.

There are no such transmissions now and I rather doubt that there'll be some in the future. In most regions there's a shortage of frequencies in the AM bands so that the occupation of two channels won't be allowed. (Not to mention that smaller bandwidth modes are more reliable for sky wave propagation.)
The 11 m band might be the only place for 20 kHz mode transmissions if it will be used by local radio stations...

Regards - DigiBC
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Old 17-09-2004, 18:29   #22
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Would'nt double bandweidth just be a simple software upgrade via the USB port of this receiver ?

Though who will use this mode and when ? Surely this is not possible on MW ?
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Old 20-09-2004, 08:56   #23
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double channel

Hi All

I believe that medium wave DRM stations will want go to double channel for two reasons.

There isn't the pressure on medium wave frequencies (at least in the UK) as suggested. All of the radio networks currently broadcasting on medium wave are also broadcasting on DAB and/or Freeview (Digital Terrestrial Television). So there is no incentive for them to spend money to switch from AM to DRM unless it can provide better quality than DAB or provide other services like multi-media, and this means DRM at 18 kHz.

Also DRM is more efficient in terms of spectrum occupancy because it can support Single Frequency Networks (SFN), which means using only one frequency irrespective of the number of transmitters or coverage area.


73s, Roger
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Old 20-09-2004, 10:21   #24
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So does this mean we could have HQ stereo on MW with double bandwidth, left ch on one, right ch on the other ?

Do you really think ofcom would allow this 'standard' to be used ? Surely they would think it was a waste of spectrum ?
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Old 20-09-2004, 11:17   #25
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Quote:
Originally posted by DRM-Fan
So does this mean we could have HQ stereo on MW with double bandwidth, left ch on one, right ch on the other ?

Do you really think ofcom would allow this 'standard' to be used ? Surely they would think it was a waste of spectrum ?
That's not how DRM works. DRM is a multi-carrier system, there is little correlation between the spectrum that the DRM signal occupies and the bandwidth of the received audio.

By allocating a double channel allows doubles the 'normal' number of OFDM carriers, which in turn (almost) doubles the available bit-rate. For example from 26.6 kbps (9 kHz spectrum bandwidth 64-QAM) to 49.1 kbps (18 kHz spectrum bandwidth 64-QAM). How this bit-rate is allocated is up to the broadcaster.

73s, Roger
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Old 20-09-2004, 22:49   #26
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Quote:
Originally posted by G8JQW

That's not how DRM works. DRM is a multi-carrier system, there is little correlation between the spectrum that the DRM signal occupies and the bandwidth of the received audio.

By allocating a double channel allows doubles the 'normal' number of OFDM carriers, which in turn (almost) doubles the available bit-rate. For example from 26.6 kbps (9 kHz spectrum bandwidth 64-QAM) to 49.1 kbps (18 kHz spectrum bandwidth 64-QAM). How this bit-rate is allocated is up to the broadcaster.

73s, Roger

OK thanks for info and excuse my total ignorance about all this. I hope it comes about then esp as we never had analogue am stereo...

www.amstereoradio.tk
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Old 24-10-2004, 00:34   #27
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So has anyone bought one of these Coding Technologies USB DRM Receivers yet? Or even know where they are available?

Would be good to see a review?
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Old 24-10-2004, 09:12   #28
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Hi BofH,
it is available in Germany from Charly Hardt , price is 230.85 Euro including taxes, plus 6 Euros for shipping to other countries than Germany. I saw a demonstration of the receiver at IBC this year, but I am not sure if it was already the final version, so no comment about the performance.
73, Simone
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Old 04-11-2004, 18:27   #29
Per
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Quote:
Originally posted by BofH
So has anyone bought one of these Coding Technologies USB DRM Receivers yet? Or even know where they are available?


Hi all,

Look at http://www.codingtechnologies.com/products/digtrav.htm
There is also an order form on the home page. But I think the product sheet contains very little information. There isn' t any information of covered frequency bands.
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Old 04-11-2004, 18:34   #30
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Quote:
Originally posted by Per


Hi all,

Look at http://www.codingtechnologies.com/products/digtrav.htm
There is also an order form on the home page. But I think the product sheet contains very little information. There isn' t any information of covered frequency bands.

Reception of Digital Radio Mondiale, analogue AM and FM

FM on SW so good for 10m FM ham band then ?! Unless it's 88 - 108 Mhz which I doubt or is it a mistake ?

A bit over priced I think half that and I may buy one

Last edited by DRM-Fan : 04-11-2004 at 18:37.
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