Tag Archives: DRM

Stefano invites you to experiment with DRM (Digital Radio Mondiale) over IP

Photo by Sergi Kabrera on Unsplash

Many thanks to SWLing Post contributor, Stefano Mollo (VK6WFM), who writes:

I have been lately experimenting with DRM 30, with the aim of coming up with a cheap solution to get on air for next to no $$$, for small, local broadcasters that would either go pirate on FM or would not go at all due to the impossibility here in Australia to get a proper FM license at a cost that does not involves selling a kidney (or two)!

I am a ham radio operator, so I turned my attention to DRM30; [the DRM application] DReaM has the capability of acting as a transmitter as well, so I started experimenting.

Click here to download DReaM via SourceForge.

I was very successful at transmitting a DRM30 / 10 kHz signal with a $ 0.50 TX module otherwise intended to transmit data with an Arduino. The signal was received with an SDR + HDSDR + Virtual Audio Cable + DReaM in reception mode.

So far, so good; with this experiment I realised that DRM 30 can, in fact, yield excellent quality at ANY frequency (as I used the 433Mhz LIPD range in my experiment) or better said, with any medium, as long as it is linear enough to transport the DRM signal.

I wanted to find a way to show the World – literally – what can be achieved with DReaM in TX mode…for free!!!

So, after some trial and error, I have set up the system below which allows anyone in the World to “tune in” my “DRM30 radio station” and listen to my DRM30/18 kHz signal, in full blown stereo. Quality is exceptional, and just imagine to send DReaM’s signal to a proper transmitter instead of streaming it over the internet ….

So…point your VLC Media Player (on Windows) to stream from:

…then pipe VLC’s output to DReaM’s input via Audio Cable (or any other Virtual Audio Cable you like).

In DReaM, select the audio cable output as the sound card’s signal input device:

Then select L+R as Channel:

Set the sample rate to the highest value:

One more thing you need to set is the “Channel Estimation: Time Interpolation” parameter to Linear; this is very important!

After few seconds you should be able my test signal, in full stereo, streamed from a PC running DReaM in TX mode, whose output is then captured by MB Recaster and streamed to an ICE Cast server I have in the Cloud. Note that no particular configuration was needed on the ICE Cast server, at all.

This is an example of what can be achieved on a solid transmission channel with DRM30 and only 18 kHz bandwidth (i.e. the normal bandwidth of an AM channel).

One can achieve the same exact audio quality using any channel linear enough to transport an 18 kHz wide DRM30 signal. It doesn’t matter the frequency, or the physical medium per se.

[…]My aim with this experiment is not to send DRM over IP; there are much simpler ways or streaming audio over IP.

Rather, my aim is to demonstrate what can be achieved with 18 kHz +DRM30 on any frequency and on any medium (which, could be for example the electrical distribution overhead lines …. just saying …. 🙂 ).

If only the local regulator would support this, instead of enforcing draconian regulations … such as the restriction of just 6 kHz on shortwave.

Please share your thoughts.

Fascinating experiment, Stefano! Thanks for sharing!

Post readers: If you’re in the mood to do a little experiment, let us know if you’re able to decode Stefano’s 18 kHz DRM30 broadcast over IP!  Please comment!

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The “Tecsun Radios Australia Q-3061” DRM Shortwave Radio

Many thanks to SWLing Post contributor, Alan Hughes, who notes that Tecsun Radios Australia have announced a new DRM stand-alone receiver: the Q-3061.

When I first received Alan’s tip, I was surprised that I had not been been given some advance notice or even a hint about Tecsun developing and producing a DRM radio. Then I saw the Q-3061 product image and it looked to be a spitting image of the Gospell GR-216 DRM radio. A quick look at the radio’s back panel and the connection with the GR-216 was confirmed.

Reading through the product description, it appears they worked with Gospell to badge this for Tecsun Radios Australia’s primary markets:

“The Tecsun Radios Australia Q-3061 DRM Shortwave Radio is for experienced shortwave users. There a limited number of DRM signals available in our region although the total number of DRM broadcasts are increasing. This radio is squarely aimed at radio enthusiasts and DXers, most signals require an external antenna, experience, and patience. We recommend our Tecsun Radios Australia Q-3061 DRM Shortwave Radio be used in conjunction with our Tecsun Shortwave and AM Outdoor Antenna for the best results (this is the setup we have in our Brookvale NSW office).

The Tecsun Radios Australia Q-3061 DRM Shortwave Radio is the culmination of several years work. Tecsun Radios Australia has worked in close co-operation with the manufacturer providing testing results from locations across the Pacific, including Samoa, Vanuatu, Solomon Islands, Fiji, and New Zealand. Reception of DRM signals in Australia requires many factors to be optimised, because we are outside the traditional coverage area of most broadcasters. Nevertheless, with an optimised antenna, correct selection of DRM broadcaster, schedule and good propagation conditions DRM signals can be received. New DRM broadcasters are appearing every month.”

After the product description they also include this disclaimer:

Note: This DRM radio has no association with Tecsun of China and is an exclusive initiative and product of Tecsun Radios Australia

The price is $500 AU or approximately $357 US.

To recap, this isn’t a new Tecsun DRM radio, rather it’s a rebadged GR-216 for the retailer/distributor Tecsun Radios Australia.

Click here to read about the Q-3061 at Tecsun Radios Australia.

Click here to read a review of the Gospell GR-216 DRM receiver.

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DRM feeds RNZ Pacific relays

(Source: Radio World via Mike Hansgen)

RANGITAIKI, New Zealand — Radio New Zealand Pacific, the official international arm of Radio New Zealand, is using Digital Radio Mondiale digital radio transmission/reception equipment to feed studio-quality audio to some of its 20 relay stations in the Pacific Ocean region. The others use satellite feeds or web downloads.

The locations being served by DRM include the Cook Islands, where RNZ Pacific’s programs are rebroadcast locally in analog mode by Aitutaki 88FM, the islands’ only broadcaster. RNZ Pacific also serves Tonga, Samoa, and the Solomon Islands using DRM; among others. Previously, RNZ Pacific had fed its relays using analog AM shortwave radio, with that transmission mode’s limited audio range and interference issues.

“When DRM became available to us in 2005, we saw it as a great opportunity to provide high quality audio to Pacific radio stations that relayed our news broadcasts from our AM transmitter,” said RNZ Pacific’s Technical Manager Adrian Sainsbury. “As a platform to deliver good quality audio to remote island FM stations, it has been a great success.”[…]

Click here to read the full article at Radio World.

As the article points out, RNZ has been using DRM as a feed for quite a few years. I think this is a brilliant use of the technology. Of course, those of us in the rest of the world can snag RNZ DRM broadcasts as well.

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PatronX Titus SDR receiver update

A number of SWLing Post readers have been asking about the status of the Titus II portable DRM/SDR radio. I’ve been checking the project website, but had not seen an update in a long time, so I contacted the company. Mike, with PantronX, kindly replied with the following update:

As you might be aware, we have joined up with Fraunhofer to include their MMPlayer app standard on Titus–what a difference a professional decoder, for both analog, DRM(+), and DAB(+), makes! MMPlayer is full featured even including reliable one way file downloads with DRM.

We are attempting also to license HD to include on the app for North America, making a truly worldwide receiver. Some deficiencies in our version of Android have caused issues as well as MMPlayer. All of which have caused delays leading to some serious business decisions – as you can imagine. You are correct that broadcasters have made large orders that will be fulfilled first. There are units in the field testing and such and continuing resolution of the software issues.

One of the issues that folks seem to have a hard time understanding is that we can not just build a few hundred or even thousands of units. Our minimum run is 10,000pcs! To do that everything has to be 100% – including the software. We simply will not ship units that are not 100%. Titus works, MMPlayer works – its that last 5% that takes the most time to resolve. These facts preclude any incremental production attempts. All that being said, we are very hopeful that the first production run is ready by last quarter of this year.

Thank you for the update, Mike!

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BBC is “keen to exploit DRM” but manufacturers must develop a multi-standard receiver chip

(Source: Radio World via Mike Hansgen)

LONDON — The BBC World Service, available on radio, TV and online, is part of one of the largest news organization in the world, the BBC.

The weekly reach of the World Service on all platforms accounted for 269 million (up from 246 million in 2015–16).

[…]Large numbers of the BBC’s audience still need international radio broadcasts.

[…]Right from its late ’90s inception, the development of Digital Radio Mondiale was fully supported and enhanced by the BBC World Service. DRM was seen as an efficient replacement for the analog AM transmissions. When we consider scarcity of spectrum for new uses and appreciate the characteristics of the radio broadcast bands, we recognize the tremendous properties these continue to offer broadcasters to deliver programs over sometimes very large distances and areas or in difficult terrain.

[…]The BBC is keen to exploit DRM in order to deliver, to key markets, BBC content free of gatekeepers in a form that can be accessed easily.

For that to be possible, the multi-standard receiver chip is required, and manufacturers must appreciate and act on this global market potential.

Click here to read the entire article at Radio World.

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