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Old 21-03-2013, 03:54   #1
tpreitzel
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De-Hamifying DRM (Digital Radio Mondiale)

This thread's purpose is primarily about simplifying reception of DRM30 on the shortwave bands as much as possible to encourage listeners without a background in radio. Reception of DRM30 on the medium wave band (AM) and DRM+ on the frequency modulation band (FM) aren't nearly as problematic due to relatively local sources compared to distant sources for DRM30 on the shortwave bands. Effective solutions will largely apply to all bands utilizing DRM30 and DRM+. Before posting, please evaluate your biases (indoctrination) to keep any recommendations as simple as possible for the aforementioned group. Assume other international alternatives, both broadcast and non-broadcast, to DRM30 do NOT exist. Please avoid esoteric language such a Q code, etc.

I have some questions for this group:

1. Where do you reside while listening to broadcasts? Include city, country, and type of residence, e.g. home, car, etc.
2. Do you know if the materials used in building your residence greatly hinder reception of local broadcasts such as TV?
3. How much time can you allocate to receiving broadcasts?
4. Can you accept the possibility of not receiving a scheduled broadcast or part of one?
5. Can you spare at least a couple hundred dollars to buy necessary equipment?
6. Are you familiar with installing and running software on a computer beyond browsing the InterNet?
7. Do you have space and permission to erect an external antenna outdoors if needed?
8. Do you understand the meaning of UTC as applied to time?
9. What factor motivates you to receive broadcasts in one of the DRM standards, e.g. cleaner audio, text, graphics, video?
10. Who can you ask for local help if needed?

I have a question for broadcasters:

Can a creative and thorough application of the DRM standards help a listener to de-hamify the experience of receiving such a broadcast? A few of a vast number of examples include periodic transmission of sufficiently detailed maps so listeners can pinpoint their location within the coverage area of the transmitter, optimal configurations based on season, advisories and rebroadcasts where appropriate due to future and past interruptions in schedule (intense solar and geomagnetic activity), etc.? Ideally, a listener shouldn't have to switch mediums for additional information on a particular broadcast as another medium may not be available.

I have a question for manufacturers of gear enabling reception of DRM broadcasts which includes antennas:

How can you continually improve your product's quality, availability, functionality, and performance to help a listener to de-hamify the experience of receiving a DRM broadcast? Quality, availability, functionality, and performance imply reliability, cost, distribution, form (interface), size, capability, etc.

I'll add more to this thread as opportunity arises.

Last edited by tpreitzel : 07-04-2013 at 08:03.
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Old 21-03-2013, 09:41   #2
Aetheradio
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Well thats a surprisingly interesting set of questions, so heres my perspective:

1. Where do you reside?>> In a wooden house in a town in New Zealand, there is a lot of radio noise coming off the power lines and telephone lines (internet ADSL, VDSL) here, making conventional radio reception increasingly difficult.

2. Do you know if the materials used in building your residence greatly hinder reception of local broadcasts such as TV?>> A minority of houses are now being built using steel framing. But this wont affect TV in NZ because its all digital now, carried on either UHF or direct to home satellite. In both cases, external aerials are used for reception. Apartments are prewired with community antenna distribution.
3. How much time can you allocate to receiving broadcasts?>>Most of the time, if its radio and portable such as built into cellphone, car radio, home stereo tuner or AV receiver.
4. Can you accept the possibility of not receiving a particular broadcast or part of one?>> No, I find a better channel fairly quickly. Of course, a DRM radio will do this automatically, and remain delivering the exact same program to me via a better frequency. I suspect the public do not know this.
5. Can you spare at least a couple hundred dollars to buy necessary equipment?>> Well thats much less money than most youth spend on cellphones and laptops, and yes i could spend that money but nothing is available. Nothing.
6. Are you familiar with installing and running software on a computer beyond browsing the InterNet?>> Yes but I dont recommend that method for someone who wants to get a better radio.
7. Do you have space and permission to erect an external antenna outdoors if needed?>> Yes but its not necessary for shortwave reception, a piece of wire thrown out the window, or buy or make an indoor loop, or use the active antenna that comes with a real shortwave ("world band radio")set.
8. Do you understand the meaning of UTC as applied to time?>> Yes, it means I have to get up at 4am to listen to "The Disco Palace" LOL
9. What factor motivates you to receive broadcasts in one of the DRM standards, e.g. cleaner audio, text, graphics, video?>> because I can. - And I believe its the best system available to do those things.
10. Who can you ask for local help if needed?>> There are a couple of other Shortwave Listeners in NZ who run similar websites

I have a question for broadcasters:

Can your shrewd use of the DRM standards help a listener to de-hamify the experience of receiving such a broadcast?>> I dont think broadcasters understand this question. Although our Radio Broadcasters Association do support the provision for DRM as a standard for future, none have started domestic transmission.

I have a question for manufacturers of gear enabling reception of DRM broadcasts which includes antennas:

How can you continually improve your product's quality, availability, functionality, and performance to help a listener to de-hamify the experience of receiving a DRM broadcast? Quality, availability, functionality, and performance imply reliability, cost, quantity, form (interface), size, capability, etc.>> In my opinion only 2 manufacturers got close to a good product, Sarapulsky and MSway. Unfortunately we didnt get the opportunity to buy them. NewStar is also highly commended for achieving what they have, however none of these radios meet the current DRM minimum performance standards - ie. they dont have DRM+ capability, let alone a high end model with Diveemo.
we have a saying here "dead in the water" - like the DAB radio I have in the office, must have cost a lot, and doesnt even pick up AM or FM stations, and cannot tune into the DAB+ station up the road, that went on air about 2005.
I think consumers dont like getting burned twice in the same decade. If you want to sell a radio, make sure it can pick up the basic worldwide standards. It doesnt cost much. The digital process chipsets available for radios are already there and have digital demodulation and Shortwave tuner, the Pioneer car radios sold here have this in them but the retailers dont know it, so the buyers dont ask for it. In theory when they add the decoding chipset required for the IBOC market it will allow the inclusion of DRM at essentially no extra cost.
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Old 21-03-2013, 10:13   #3
tpreitzel
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Aetheradio,

Maybe just contemplating and then communicating answers to these and other questions can serve as a bridge of communication between broadcasters, manufacturers, and listeners.

More later ...

Last edited by tpreitzel : 21-03-2013 at 10:28.
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Old 06-04-2013, 23:20   #4
tpreitzel
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Add periodic transmission of accurate and comprehensive schedules of ALL DRM broadcasts from a particular broadcaster. Broadcasters, STOP viewing DRM as merely a higher quality version of analog and START using DRM's digital capability to inform the listener. The current situation of forcing the listener to search through reams of data from inaccurate (including outdated) and incomplete schedules is ABSURD and UNNECESSARY.

Last edited by tpreitzel : 07-04-2013 at 08:05.
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Old 08-04-2013, 15:55   #5
F1BJB
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Hi
In short my opinion is that to dé-hamify radio reception it must be computerified.
For ages I used my computer to watch and record TV.
Set top boxes are a very poor and costly alternative only justified by payTV.
The ideal radio receiver for me is a black box connected to aerials on one side
and to a local network on the other.
Self contained receivers should be network compatible for updating,recording
and printing.
Able to deliver and listen to a network stream too.
As far as my receiving conditions are concerned I can say that I am lucky.
This and the use of a low cost SDR receiver are the reasons for my late
come back to short and medium wave listening.

Last edited by F1BJB : 08-04-2013 at 15:57.
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Old 08-04-2013, 21:52   #6
tpreitzel
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Broadcasters could even transmit periodic surveys digitally which could then be sent to a printer on a local area network (LAN) for mailing. Personally, I have no problem with networking a receiver to a LAN. However, I, personally, wouldn't want my receiver connected to a wide area network (WAN) such as the InterNet, e.g. RadioDNS, which might possibly identify the location of the listener. * Risk of identification of location rises with transmission. The WAN should exclusively be a connection by radio with the broadcaster bearing the sole responsibility and risk for informing the listener. Until the technological and legal aspects of radio allow for unlicensed full duplex communication (greater risk and impossible over longer distances?), a listener can always use postal mail, telephone, radiograms, InterNet, etc. for feedback to a broadcaster when needed. Notice the listed feedback mechanisms involve a third party, the owner of infrastructure, which can allow or disallow communication between two parties. Automating radio functionality as much as possible is logical as systems become increasingly capable and complex.

* See the thread, "Why Shortwave is 'Hear' to Stay"

Last edited by tpreitzel : 09-04-2013 at 07:17.
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Old 23-06-2013, 09:06   #7
F1BJB
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Hi
I agree .
AFAIK the data capabilities of DRM are not very useful.
Using them for schedules and frequencies would be a good idea
Another thing missing is the possibility to record the full transport stream.
This would allow later computer processing of it like printing of time tables or QSL cards.
One could even imagine merging several recordings of the same transmission
from various places in order to correct errors.
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Old 17-09-2013, 05:44   #8
tpreitzel
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xHE-AAC

The new extended HE-AAC v2 codec is a major development in simplifying the decoding of quality DRM broadcasts for the average listener. Until DRM broadcasts are much more plentiful, the majority of broadcasters should adopt 16 QAM for the MSC, lower their bit-rates to ~ 14 kbps and use xHE-AAC. Do it, broadcasters!

Last edited by tpreitzel : 17-09-2013 at 10:16.
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Old 15-10-2013, 07:22   #9
tpreitzel
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A nice article outlining the need for appropriate ergonomics.

http://www.drm.org/?p=2529
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Old 15-11-2013, 07:25   #10
tpreitzel
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Reception at my location over the past two weeks has been poor due to the vast number of solar flares and their concomitant effects on the geomagnetic poles of the earth. Do broadcasters honestly expect their listeners to tolerate the inability to receive their broadcasts for two weeks? Clearly, nearly ALL digital broadcasts are demonstrably underpowered in less than ideal conditions. Furthermore, more broadcasters along with the HFCC need to allocate more spectrum of the 60, 49, and 41 meter bands to digital broadcasts as well. Either broadcast digital in the 60, 49, and 41 meter bands or be exiled to the 13 meter band!

Since beginning to listen to shortwave a couple of years ago, this stretch is the worst that I've encountered thus far.

Last edited by tpreitzel : 15-11-2013 at 07:39.
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Old 15-11-2013, 08:27   #11
Linux-DRM
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Prop

Yes, propagation has taken a battering recently (I blame the sun ).
'Low powered' DRM transmitters are borderline for me right now unless they are within a 1500km radius, more than likely due to my high latitude and high occurrences of solar flares.

I work on the premise that if you can't receive a shortwave broadcast with basic equipment it defeats the purpose (for me at least).

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Old 16-11-2013, 09:03   #12
DRM-OM
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Quote:
Originally Posted by tpreitzel
ALL digital broadcasts are demonstrably underpowered in less than ideal conditions.
Note that total DRM power is limited to max. 40% of analog CARRIER only power for technical reasons. So don't expect more power - the operator would have to upgrade the equipment completely, not just buy an exciter.
This is a feature.
DRM is "sold" to transmitter operators with the arguement to save energy = money!

b.t.w.
Quote:
Originally Posted by http://www.drm.org/?page_id=105
In France, where the regulatory authorities have already approved DRM as the digital successor to Medium Wave, two transmitters will cover the entire country.
sorry, but this is ridiculous

Last edited by DRM-OM : 16-11-2013 at 12:16.
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Old 13-11-2017, 01:23   #13
zfyoung
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Quote:
This problem can only be resolved through sane configurations appropriate for shortwave, i.e. MSCs of 16 QAM, and the xHE-AAC codec
This is the only short term stopgap solutions to the HF broadcast problem.
Actually the main complaint I have against DRM is that the codec (AAC+/xHE) remains proprietary product. This not only put a hurdle on wider adoption of modern broadcast standard, it also discourage any attempt to improve or it co-opted to better systems. And indeed there is a far better solution to this kludge: why let the broadcaster to dictate the configuration of transmission signals (64/16QAM, bitrate, AAC/xHE etc.) at TX side, why NOT let the receiver to decide that at RX side depending on the local SNR level? This strategy incorporate the agility of analogue system and efficiency of digital system and DX friendly.
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Old 13-11-2017, 21:00   #14
tpreitzel
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Quote:
Originally Posted by zfyoung
This is the only short term stopgap solutions to the HF broadcast problem.
Actually the main complaint I have against DRM is that the codec (AAC+/xHE) remains proprietary product. This not only put a hurdle on wider adoption of modern broadcast standard, it also discourage any attempt to improve or it co-opted to better systems. And indeed there is a far better solution to this kludge: why let the broadcaster to dictate the configuration of transmission signals (64/16QAM, bitrate, AAC/xHE etc.) at TX side, why NOT let the receiver to decide that at RX side depending on the local SNR level? This strategy incorporate the agility of analogue system and efficiency of digital system and DX friendly.


If you're implying that the DRM standard has asymmetric ability, then I was unaware of that capability. As Laurent suggested, dynamic capability certainly would be better than any static configuration, but asymmetric capability is another matter entirely. Explain to me how your scenario would work with the DRM standard both technically and experientially. Keep it simple and, if appropriate, use the DR-111 as the receiver in any example.

Are you suggesting that if a broadcaster used a 64 QAM configuration, then the DRM standard allows for the asymmetic reconfiguration at the receiver to 16 QAM?

Personally, I support the concept of dynamic configuration at the RX, but I think it's best to place the onus on the broadcaster for the foreseeable future. Yes, the BBC still broadcasts automatic frequency changes when no such frequencies exist and most digital broadcasters can't even broadcast time signals correctly, etc...

P.S. I'm pretty sure that Laurent and yourself are thinking in terms of TX initiated reconfigurations while I'm thinking in terms of RX initiated reconfigurations (adaptions since the RX can't talk to TX) .... For example, I'm outside the target area of a broadcaster, but I want my receiver to decode the digital broadcast if possible. Hence, I need it to switch to a mode where decoding is possible ... IF possible.

Last edited by tpreitzel : 14-11-2017 at 00:43.
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Old 14-11-2017, 00:49   #15
zfyoung
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Quote:
implying that the DRM standard has asymmetric ability
If you confine yourself within the 'rule box' of current DRM standard, then the answer is a resounding NO. That's why I said
Quote:
short term stopgap solutions
. But it does't mean you have to throw out the baby with dirty bath water. what I hinted is that there is Long Term Evolution of this standard (L.T.E. sounds familiar, eh?)that in the ultimate end brings out the best of analogue system and digital system.

PS. NO, laurent and I are talking about two different things, and given my academic background in information theory I know what I'm talking about: "Joint Source Channel Coding". If you not even heard about it, then google it.
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Last edited by zfyoung : 14-11-2017 at 00:57.
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