Radio in a 5G World
Kevin Ryan considers the future of digital radio, installs the welle.io app on an Android tablet
Kevin Ryan considers the future of digital radio, installs the welle.io app on an Android tablet, offers highlights from IBC 2018, reports from Norway and Gibraltar, and has news on DRM+ and DAB changes.
There are many stories circulating at the moment, in connection with the perceived, urgent, need for digital radio, especially DAB+, to create a long-term future for the technology.
In the UK, we would probably like to have DAB+ first, before thinking about the next leap in technology.
The broadcasters want to reach everybody, if possible, and national stations are obligated to do this by the Government. Meanwhile, the younger generation is increasingly unaware of radio. The very youngest members of my family don’t really know what a ‘radio’ is, as their world is all video-based.
Most radio listeners are drifting to podcasts and smart speakers, and they use their mobiles for almost everything. I am not surprised at this; stations like BBC Radio Five Live rarely mention digital radio and are more likely to suggest listening via the radio app, podcast or a smart speaker. Many mobiles include an FM radio, but how many have a DAB radio? I have only come across one, a few years ago.
5G on the Horizon
There is speculation – from broadcasters mainly – as to whether the latest mobile telephony technology called 5G (‘fifth-generation’) will make DAB+ and other digital radio systems obsolete.
The UK mobile telephone operator EE started the first 5G trial, in Canary Wharf in London, in early October, and more of them will follow in the big cities. These are mainly engineering tests of the 3.4 GHz spectrum, and of devices like new consumer handsets. The network itself will not be widely available until 2022.
Why the panic on the part of the broadcasters? These alarm bells are not new, and a similar critical (and negative) analysis was published periodically by the DAB community during 2010-2014 when 4G technology appeared in more countries. That perceived crisis didn’t happen back then, but the risk is back in the shape of 5G and its much greater data download capacity.
I noted during a BBC Five Live interview with Marc Allera, the Chief Executive of EE, that neither he nor the BBC presenters mentioned radio. They referred to the fact that a full HD film could be downloaded in under 40 seconds, using 5G, compared to over seven minutes on 4G.
There is a difference between delivering sound over a broadcast network and via mobile. The latter is an extension of the internet and you are streaming a radio programme, either live or as a podcast, using up mobile bandwidth that has to be paid for, by either the broadcaster or by you and me – in some cases by both parties. Radio broadcasts, by contrast, are thought of as ‘free’, even though they are paid for by the consumer, either through a licence fee or through what we buy.
In my opinion, broadcast networks will continue, because they are much cheaper to run than a mobile network – by a factor of about 10:1. DAB+, for example, covers a wide area with a handful of transmitters, whereas 5G would require hundreds (some estimate thousands) more to achieve the same coverage.
One author estimated that Norway would need 765 DAB+ transmitters to provide 99.5% of geographical coverage and that 4G would need nearly one million mobile cells to achieve the same thing.
Another interesting aspect of mobile is that, at peak times, there may not be enough capacity to deliver everything that people want, and that bandwidth might be ‘throttled back’, thus impacting streaming.
Furthermore, in a 5G mobile environment, many users would be passing from one microcell to another very quickly. This is a headache in terms of seamless access (no audio dropouts) to your favourite radio show.
A Future Role for DAB?
Nearly all these comparisons are produced by the DAB community, after proving – to themselves at least –
that mobile can never replace broadcasting. By contrast, I nearly always conclude that the future will be a ‘hybrid’ one, where DAB+ and 5G can, and will, complement each other.
Many now say that radio, in general, is losing its identity and becoming a ‘podcast-factory’, for want of a better analogy. Radio is now also in danger of being pushed out of the car dashboard, it seems, where many people do most of their radio listening.
There are ideas on how to make digital radio more interesting and relevant, and I covered one of these developments (Project Orpheus) in this magazine before (RadioUser, August 2018: 52-55).
IBC 2018 Highlights
Many new product announcements were made during the International Broadcasting Conference (IBC), and, as always, I was on the lookout for new digital receivers.
One thing that caught my eye was the unveiling of a prototype for a voice-controlled, hybrid, radio. The radio combines broadcast and IP-radio (streaming) technology. Those radios already exist today, and they offer voice-command technology, by means of which users can choose which source to use. This means that the listener requests a station, and the computer decides on the source.
There is a pertinent info sheet on the EBU technical website; the prototype combines Alexa voice control with a Frontier Smart Technologies DAB/FM module.
The PILOT-funded (Fig.1) project will develop the software that makes them work together, and the group will release the code to manufacturers for use in their receivers.
News from Norway
It is hard to believe that, one year ago, Norway was in the process of switching off most of its FM transmitters. Jon Branaes, Head of Radio for the national broadcaster NRK, in a frank interview with RadioWorld, said that the switchover process is not yet over.
There was a mixed reaction from radio listeners, with many happy to have the extra choice provided by the increase to 15 NRK channels, and from lobbyists who still want to oppose DAB. Facts are being selectively used by different groups, both inside and outside Norway, to support, or argue against, a switchover to digital.
By contrast to this, it is clear from independent media research that radio listening had declined on analogue by mid-2017 and started to recover again the following spring, after the digital switchover. Has digital re-invigorated radio listening or would it have happened anyway? It is difficult to know, but it is possible that the move to digital forced people to use DAB and discover the additional channels.
Jon Branaes is adamant that FM was not the future because it provided limited content, not forgetting that DAB can indeed carry more stations but is also limited, in the age of the internet and streaming. Like many senior radio figures, he sees the future, once again, as a ‘hybrid’ of DAB+ and internet streaming.
A new radio station called Rock Radio (Fig. 2) started in Gibraltar on October 1st, both on DAB+ and FM. Curious to know what was happening in this distant part of the UK, the WorldDAB agency produced an interesting story. It stated that, “Two DAB+ ensembles operate on Blocks 12B and 12C, and the new radio networks went on-air on 31 December 2012, allowing Gibraltar to switch off analogue television.
“There are currently no plans to switch off FM radio in Gibraltar. The incumbent national broadcaster is transmitting four radio stations, which are re-transmissions of the same content that is currently being transmitted on the FM network”.
The digital broadcasting network, comprising of two digital television multiplexes and two digital radio multiplexes, became operational in December 2012, allowing Gibraltar to meet its obligation to cease analogue TV transmissions.
There were two (Band III) TV transmitters in operation, but they were not on the same frequencies as the new DAB+ transmitters, which makes the above WorldDAB news item a bit odd. The TV switchover could have gone ahead without installing DAB+ transmitters.
The DAB+ transmitters are located on the Upper Rock at Signal Hill, and each digital radio multiplex can carry four distinct programmes. At the moment, they transmit two on each multiplex; all four of them carry the same audio. So far as I know, there was no obligation to have DAB+ installed. Perhaps this was an example of forward-planning. In Southern Europe in general, there is no central push f9or the promotion of digital radio.
In Gibraltar, only 8% of the population tune in via digital receivers.
A third, small-scale, DAB multiplex came on air on channel 11A in August in Cork, the second largest city. It has a trial licence for one year (Fig. 3). There are two other multiplexes in Dublin, transmitting from the Raidió Teilifís Éireann (RTE) headquarters in Donnybrook.
So far, just two religious broadcasters are using the Cork multiplex. The power is 300W, and the predicted coverage area is comparable to that of RTE’s 10kW multiplex.
There is speculation that RTE may close down DAB as a cost-saving measure. RTE’s 2018-2022 Strategy doesn’t confirm this, but it states that DAB will not be expanded beyond the current level, without the involvement of the Government and the commercial sector.
RTE favours the continuance of FM, in addition to more streaming and podcasting. If the small-scale DAB trials are successful, I think that the commercial stations, many of whom are quite small, might be attracted to that option as a means of going digital.
Welle.io on Android
Regular readers will already know about the welle.io software app for DAB reception. They will also be aware that I had problems with its stability on Windows 7. It works much better on Windows 10, but you may not know that there is a version for Android that works with RTL-SDR devices.
The Google Play store lists the basic requirements for your devices: “Welle.io uses the rtl-sdr driver from https://play.google.com/store/apps/details?id=marto.rtl_tcp_andro. Additionally, you need an rtl-sdr USB dongle, which has to be connected to your phone via an USB-OTG cable. This app is very computation- intensive. You need at least a 4-core CPU with 1.3 GHz for using this app.
“Please note that welle.io is under heavy development.”
My Acer Iconia Tab 10 has four cores and a 1.5 GHz CPU. I downloaded the rtl-sdr driver, which remains dormant until a hardware device is plugged in.
You may not have come across a USB-OTG cable before. USB On-The-Go (OTG) is a standard for USB connections. It allows a device to read data from a USB connection without a PC. These cables are available on the internet, and I recommend that you search for one compatible with your tablet. There are apps on the Play store that check if your device supports OTG, but they only check the software.
The specification for the Acer tablet listed the side-micro-USB port as supporting OTG, Slave-USB-connection and Power-over-USB. The top USB port only has OTG support.
I plugged the cable and the SDR into the side-micro-USB port that I use to charge the tablet, but that didn’t work. Subsequently, I moved the OTG cable to the top USB connection, and it powered the SDR; this was almost the reverse of how I interpreted the specification.
If you only have one micro-USB, or if none of your USB ports works, try an OTG cable with micro-USB- power to drive the SDR. They are not expensive, but they can take a while to get to you from China.
I used the NooElec NESDR mini 2, which I had problems with during my first test of welle.io.
On Android, welle.io worked very well and was stable; however, my tablet has just enough processing power to run the app and nothing else. If you plan to use any other app while running welle.io, you will get audio-breakups. It also took the app a short while (less than a minute) to settle down when I changed the station. After that, it was stable and decoded both DAB and DAB+.
The Google Play store indicates that the app should decode slideshows (Fig. 4). However, apparently, this is not the case if these are carried as separate data streams, as with Capital London and Heart London.
Stations in Germany put the images into a part of the main DAB data stream (MSC or Main Service Channel) called Programme Associated Data or PAD.
Welle.io on Android is very stable, and it ran for a couple of hours on my tablet without any reports of low signal. Nevertheless, this did happen occasionally.
The SDR was connected to a DAB antenna in my loft.
In expert-mode, there is a display of some technical parameters, along with a spectrum. In landscape mode (Fig. 5), it is a bit compressed in the middle. And in portrait mode, you are able to scroll between the three panes (Fig. 6), but you will need to be careful not to select another station.
My test station was the BBC World Service, and there was an occasional ‘audio-warble’, due to decoding errors. However, the app recovered quickly, unlike what happened during my Windows 7 tests.
The expert-mode display revealed FIC errors. The FIC (Fast Information Channel) carries the multiplex configuration information. Errors became more frequent as battery capacity dropped to below 20%.
It may be that the tablet was switching non-essential bits off and was using CPU time to do this.
Three countries are going to use DRM+ for any move to digital in Band II. Russia will use it in Band I as well. All India Radio (AIR), the national broadcaster, wants to use it, but the standard hasn’t been approved by the regulator. South Africa recommends its use in Band II, impressed by the way a DRM multiplex can slot into the spaces between existing FM stations. DAB+ is the choice for Band III there.
Another DRM Receiver
A new low-cost, all-band, DRM receiver from Germany was unveiled at IBC 2018. I saw a grainy picture of the receiver, but I could not make out much detail (Fig. 7). The logo looked familiar; it belongs to Starwaves, a company that made a couple of prototypes from 2005 to 2007, covering both DAB and DRM. Like most DRM receivers, they were only manufactured in small numbers. Their website is live, but it is a decade or more out of date and currently only of historic value.
The new shortwave and DRM broadcast schedules came into effect at the end of October. I always read them with mixed feelings to see whether digital broadcasts have increased, or whether one or the other of its major supporters has abandoned them completely. It would be a major blow if either the BBC World Service or Radio Romania International decreased their output.
We can only hope that All India Radio and Radio Kuwait will address their transmitter problems and erratic schedules. US broadcasters keep hinting that they are keen to start digital services, but only WINB took any action with their strange, hybrid, service. As I warned before, the DRM section produced by the HFCC is partly pure fiction, since it includes countries that do register a service year on year but have stopped shortwave broadcasting several years ago.
As this is the last edition this year I want to wrap up some of the news items from 2018. I found a webpage on the Arqiva (transmitter operator) website, and it contained details of transmitter locations of an additional 19 transmitters. According to a press release, the project was ahead of schedule, as of the end of September 2018. It will increase UK population coverage to 83%. The areas I wasn’t sure of are Swindon, Daventry, and the Ridge Hill transmitter site in Herefordshire.
KiwiSDR and Dream
When using the KiwiSDR remote receiver network to decode DRM with the DReaM DRM software, I have previously suggested using the I/Q Pos Split mode for the channel setting. I have since found that the I/Q Pos Zero option works well on many stations. The mini-tutorial on KiwiSDR and DReaM can be found in the October issue (RadioUser, October 2018: 30-33).
Medium wave stations broadcasting in the DRM mode used the xHE-AAC decoder. This is not supported by DreaM. Lately, the New Delhi station, using pure DRM, went back to using HE-AAC, and I can now get the occasional burst of audio. The signal-to-noise ratio (SNR) is terrible and the audio only ‘locks-on’ for a couple of seconds at a time. The other Delhi station on 828kHz (simulcasting the analogue programme on 819kHz) has not changed to AAC. Once a day, between 1000 and 1100 UTC, it changes to pure DRM, which should be on the analogue frequency. There is a video of the reception on a Gospell receiver on YouTube.
Using the Delhi SDR, I found that the DRM bandwidth was wider than normal. The IQ filter in the KiwiSDR must be stopping some of the signal, to the extent that I found it very hard to get DReaM to lock onto it. The centre frequency (so far as that applies to DRM) was probably 823.5kHz. The signal was very strong, and it was possibly overloading the SDR.
The 4770kHz Signal
The unidentified DRM signal on this frequency is most likely a transmitter run by the Swiss Government. It might be used as an Emergency Warning System (EWS) for people in the remote mountains.
I base this on a conversation Jeff Whyte of WRMI had with an Ampegon engineer at the High-Frequency Coordination Convention (HFCC) conference in Bratislava.
It aired on the Wavescan media programme, which was carried by Adventist World Radio (AWR) during its English broadcasts on shortwave on Sundays.
However, the programme failed to mention the ‘small problem’ of the lack of receivers. This signal is reported to be like the one carried on WINB on 15670kHz. Here, the 10kHz bandwidth is shared equally between DRM and an unknown data signal, and this will require a bespoke receiver. DRM has an EWS mode of its own. I can only speculate as to the other data that would need to be sent alongside weather and other emergency messages.
This all-mode receiver (Fig. 8) for digital broadcasts was due for general release about the time that I was writing this column. I am going to stick my neck out and predict that this will not happen, which is a shame. I haven’t seen or heard an update in many months, and I guess the manufacturers are having problems adding an HDRadio decoder to their SDR.
DAB is looking to secure its long-term future by merging with mobile, streaming and voice control technologies. If this works, digital radio will exist in its own right, and as a part of the new, connected world.
I think it is a clever way to go. It will take years, if not decades, to deliver this vision, but radio enthusiasts can live with that.
This article was featured in the December 2018 issue of Radio User