Curtain Antennas at the Edward R. Murrow Transmitting Site.
Many thanks to SWLing Post contributor, Marc Pascoe, who, in response to this article from The Spectator posted last week, shared a thought-provoking piece from ARK on the dangers of phasing out shortwave broadcasts.
The ARK article highlights the critical role shortwave radio has historically played in providing access to information, particularly for rural and underdeveloped regions where internet penetration remains low. Despite digital media’s rise, approximately 37% of the global population still lacks reliable internet access, making shortwave a vital tool for delivering news, emergency alerts, and educational content. The reduction in shortwave services risks isolating these populations, especially during crises when conventional communication networks may be unavailable or compromised.
Additionally, the article underscores the increasing vulnerability to censorship, propaganda, and misinformation as shortwave broadcasts decline. Unlike the internet, which can be easily controlled or restricted by authoritarian regimes, shortwave signals are resilient and difficult to jam. Historical examples from North Korea, Iran, and the war in Ukraine illustrate the crucial role shortwave plays in ensuring the free flow of information.
The first thing its the lack of technical knowledge of the management of broadcasting organisations.
The telco companies have been on a campaign to convince broadcasters that they are old technology and that streaming is the way to go for their own profits. As a result the BBC wants to go all streaming which transfers the cost of delivering their content to the listener to the listener. Following the BBC the ABC Australia has been strongly pushing streaming for a considerable time, but even so only 20 % of the listeners are streaming. Streaming uses a lot more electricity compared to pure digital broadcasting.
AM technology is used in the majority of high frequency broadcasting. 67 % and more of the transmitted power in AM contains no sound information. The transmitter not only has to produce that extra power but it requires extra cooling is very expensive in high power transmitters. So the accountants in broadcasters say cutting will save lots of money. Against this it is not possible to find out accurately how many listeners there actually are
With the advent of the Software Designed Radio the cost of adding high frequency tuning is almost non existent and this is the latest development. In addition the Digital Radio Mondiale is available in these bands are of FM quality including stereo sound. It also can contain extensive multilingual text along with pictures which can be used in emergencies as well as for education all without the internet and mains powered electricity. https://youtu.be/lqQ-fodAH4E . The DRM1000 is a receiver module uses Software Designed technology which does everything from the antenna input to an output for speaker at a low cost. There is another receiver which contains a Wifi hotspot so that tablets can show larger colour images good for education and emergency information.
DRM does not have a carrier saving all that electricity thus cost and also reduces the generation of greenhouse gasses.
> As a result the BBC wants to go all streaming
What is the source of this information?
> In addition the Digital Radio Mondiale is available in these bands are of FM quality including stereo sound.
It is not, DRM can do max 30 kbps on HF, which results in a horribly distorted audio ridden with digital compression artifacts. The quality is abysmally low, it sounds unnatural and the signal is prone to fading resulting in dropouts. Even the late 90s dialup could do 56 kbps, DRM is worse than dialup.
> DRM1000 is a receiver module uses Software Designed technology
Its datasheet does not say that.
> There is another receiver which contains a Wifi hotspot so that tablets can show larger colour images good for education and emergency information.
What is the manufacturer and model? Where it can be bought?
> DRM does not have a carrier saving all that electricity thus cost and also reduces the generation of greenhouse gasses.
DRM does not reduce the generation of greenhouse gases. In fact, no radio transmitter, be it analogue or digital, generates them. In order to lower the generation of greenhouse gases, you have to supply a radio transmitter (again, no matter what type) with renewable energy. Switching to failed digital transmitting mode from 20 years back wouldn’t help with that.
TIm Davie Director General BBC
DRM specified xHE AAC Have a listen https://youtu.be/SGLBKz9Q_XQ. There has been big developments in the last quarter of a century since the same technical university developed MP3
High frequency broadcasting you can hear the woman on the left and the man on the right. Path length over 5000 km.
Have a look at a photo of the inside of the DRM1000 module and show me the evidence that it is not an SDR design by looking at the components. It is made by a computer component manufacturer. All of the recently reviewed radios on this site are also SDR radios.
https://www.drm.org/products/desktop-and-portable-radios/
In the VHF band a 10 kW FM transmitter coverage area carrying one program is covered by a 1 kW DRM transmitter carrying 3 audio channels and a data channel.
Below 30 MHz you had better go an brush up on your AM theory. DRM does not have a carrier.
How many radio transmitters are powered from renewable power, particularly the high power ones?
https://youtu.be/XpGML1JITio and now there are 7 million cars which are DRM equipped prior to delivery and this number is rapidly rising. Compare this to the single all digital transmitter in the USA and nowhere near 100 % terrestrial digital reception in all new vehicles.
https://www.nautel.com/resources/webinars/am-transmitters/building-for-a-billion/ compared to the USA’s single MF band pure digital transmitter
> TIm Davie Director General BBC
The fact that the Director General said something in some interview does not mean that the company has adopted such a policy. He is, after all, a director, not a dictator.
> DRM specified xHE AAC Have a listen
Stop watching these advertisements, instead listen to a demo of a live DRM broadcast in India.
https://www.youtube.com/watch?v=UuXkb8JTVV0
https://www.youtube.com/watch?v=k4P11aSqlcI
Horrible audio distortion. Worse than a phone call!
> There has been big developments in the last quarter of a century since the same technical university developed MP3
Agreed! There have been big developments in all technological fields, but none of them got adopted by DRM. In 2001 it could do 30 kbps on HF, now we have 2025 and it still do 30 kbps.
> Have a look at a photo of the inside of the DRM1000 module and show me the evidence that it is not an SDR design
Its datasheet is the evidence.
> All of the recently reviewed radios on this site are also SDR radios.
Which ones? Are we actually looking at the same site? The recently reviewed radios I can see are: Sony ICR-N20, SIHUADON R-108, Lowe HF-150, Tecsun PL-660, Qodosen DX-286. These are the receivers from the 10 latest pages. None of them are SDRs.
> https://www.drm.org/products/desktop-and-portable-radios/
I cannot see any “Order now” button – this is just a website with pictures.
> Below 30 MHz you had better go an brush up on your AM theory.
You’re absolutely free to point out where I’m being wrong.
> How many radio transmitters are powered from renewable power, particularly the high power ones?
In what way is this relevant to your claim that DRM “reduces the generation of greenhouse gasses”? Or how is that supposed to disprove my point that radio transmitters do not generate them?
> now there are 7 million cars which are DRM equipped prior to delivery and this number is rapidly rising. Compare this to the single all digital transmitter in the USA and nowhere near 100 % terrestrial digital reception in all new vehicles.
Better not to have digital reception at all if it’s going to sound the way it does in India!
It is BBC policy because the Government is going to stop paying them licence fees from viewers.
If you can get good quality sound from a compression algorithm, then it is not the cause of high distortion. Distortion occurs if audio is decompressed and recompressed particularly from a different algorithm, along with what happens in studios.
I have listened to BBC HF DRM many times and distortion was not a problem.
Just because a specification sheet does not say it is a SDR it doesn’t mean it is not one. How do you prove they are superhetrodyne designs?
Go to the company website.
Simple much less electricity consumption means less CO2 production in many countries, even if renewable power the size of solar panels and batteries is greatly reduced as does the cost of the power source and of course the transmitter.
In Australia we had DAB+ with lots of broadcasters using 32 kbit/s stereo. I receive them in my car and it much better than AM.
Why would the car manufacturers in India install such a distorted sounding system in their cars? It would drive customers away. You have never been in an Indian care listening to its DRM radio so how do you know!?
Your examples are not car radios! Secondly all of those demos on line that I have seen use a camera microphone pointed at the windscreen to record the sound in an echoic and noisy environment. One of the few examples where a monitoring receiver wired output was used is the link from KTWR below.
Your sound quality examples are like I used to get when I was a kid. Point a microphone at a speaker and expect good sound even in analog audio! The first example has a tiny speaker inside a metal box. How about getting the audio out put from a real receiver not a computer? Why not listen to the real thing.
Listen to a KiwiSDR at http://www.tecsunradios.com.au/store/tecsun-sw-radio-online/ which is located on the South Coast of NSW Australia. The receiver is in the opposite direction to the main signal strength going to the South Pacific from Radio New Zealand. The signal is much weaker than the prime target https://www.rnz.co.nz/international/listen for times and frequencies. It has been doing this since 2004. Now at least the audio data stream does not go through speakers and microphones and the data remains compressed.
Do any of the receivers you quote say they are superhetrodyne (old fashioned) designs? They don’t say they are SDR either. You are making these claims you prove it.
What is a https://www.skyworksinc.com/en/Products/Audio-and-Radio/Si4734-35-AM-FM-SW-LW-Radio-Receivers/Si4734 chip then?
I have never said that the transmitter itself produces greenhouse gasses. It is the electricity supplier which can do that.
The missing link to the stereo sound trial
https://soundcloud.com/digital-radio-mondiale/sets/ktwr-drm-test-broadcast
It’s worth listening to on headphones or a stereo speaker system
> It is BBC policy because the Government is going to stop paying them licence fees from viewers.
It it’s a BBC policy, you should be able to provide us with the BBC’s announcement stating they “the BBC wants to go all streaming”. Such a statement for a decision that’s supposed to be already made should include, among others, a timeline for this transition. Where can we find it?
> If you can get good quality sound from a compression algorithm, then it is not the cause of high distortion.
You can get a good quality signal, just not with such abysmal bitrates as those offered by DRM.
> I have listened to BBC HF DRM many times and distortion was not a problem.
I have listened to multiple HF DRM broadcast and the distortion was always horrible.
> Just because a specification sheet does not say it is a SDR it doesn’t mean it is not one. How do you prove they are superhetrodyne designs?
Kindly please stop putting words in my mouth. I am not going to provide proofs for points I have not made. The only mention of the term ‘superheterodyne’ is in your comment – not mine.
> Simple much less electricity consumption means less CO2 production in many countries, even if renewable power the size of solar panels and batteries is greatly reduced as does the cost of the power source and of course the transmitter.
I can’t understand what a “course of the transmitter” may be, but I think we could agree that the general direction to help the environment would be to switch to renewables not just for the radio transmitters, but for the whole electricity grid.
> In Australia we had DAB+ with lots of broadcasters using 32 kbit/s stereo. I receive them in my car and it much better than AM.
My condolences for having to listen to such horrible audio! It’s really worse than a phone call. Modern VoLTE systems can do as much as 128kbit/s. This is how much outdated these digital radio systems are. On the other hand, Australia has some AM stations that transmit high quality audio with wide bandwidth, like this one from Sydney: https://www.youtube.com/watch?v=MSR057Aekc8. Your car receiver probably wouldn’t be able to receive it so well because they are often equipped with narrow filters that reduce the audio bandwidth.
> Why would the car manufacturers in India install such a distorted sounding system in their cars? It would drive customers away.
These are not DRM-only radios, they also receive analog broadcasts. We do not know whether the digital capabilities are actively used at all. The fact that it’s offered for some new cars (a very small percentage of the Indian fleet) does not mean that DRM has gained any significant relevance there in terms i.e. of actual listening hours.
> You have never been in an Indian care listening to its DRM radio so how do you know!?
I think the same applies to you or am I wrong there?
> Your examples are not car radios! Secondly all of those demos on line that I have seen use a camera microphone pointed at the windscreen to record the sound in an echoic and noisy environment.
Quite not all, you can easily find other ones, captured without the use of a camera, like these here:
https://www.youtube.com/watch?v=OgyVgajht4A
https://www.youtube.com/watch?v=ZFTe6LWqYW4
https://www.youtube.com/watch?v=Eda-Gpholnc
https://www.youtube.com/watch?v=wjIvYfWs0u8
They still sound as bad as those 80s C64 speech synthesizers, though.
> How about getting the audio out put from a real receiver not a computer? Why not listen to the real thing. Listen to a KiwiSDR at http(…)
I’m getting lost with this line of reasoning, because I’m pretty sure that listening to a KiwiSDR would inevitably require the use of a computer, which would be something you seem to discourage.
> Do any of the receivers you quote say they are superhetrodyne (old fashioned) designs? They don’t say they are SDR either. You are making these claims you prove it.
My apologies, but this is getting a bit ridiculous. Are you seriously requesting me to provide proofs that a Sony ICR-N20 (from the late 1990s) or a Tecsun PL-660 is not a SDR? You could as well ask me to prove explicitely that water is wet, because it doesn’t say so on the bottle.
> What is a https://www.skyworksinc.com/en/Products/Audio-and-Radio/Si4734-35-AM-FM-SW-LW-Radio-Receivers/Si4734 chip then?
It’s a low-IF receiver.
> I have never said that the transmitter itself produces greenhouse gasses. It is the electricity supplier which can do that.
Absolutely! No DRM needed for that.
This is just another post from a long and never ending campaign against a new technology which was not invented in the USA and has not been adopted anywhere outside of North America in 24 years because of its poor design. Your campaign is based on Internet trawling instead of listening to real signals on real radios. I am not talking of the first reception of using a superheterodyne radio’s intermediate frequency output converted by another oscillator to 12 kHz and then fed into the audio card of a computer loaded with the free DREAM program which has been flaky software from the start. An issue with this approach is that there is no frequency error signal (labelled DC error) fed back from the computer to the local oscillator in the receiver to make sure the demodulator is working on the exact channel centre.
‘DREAM’ software is not from the inventors https://www.iis.fraunhofer.de/en/ff/amm/broadcast-streaming/xheaac.html who have to receive patent payments. All DRM manufactured receivers and Microsoft for Windows 11® have to pay these payments. This software will give the best sound.
Almost all demonstrations of sound quality of reception particularly videos have used the camera microphone pointed at a speaker. This always gives much poorer quality sound than a line output into the line input to the recording device. Thus, assessments of sound quality are always poorer. As a result, I have suggested to listen to some examples in stereo done by a broadcaster using monitoring receiver and a wired connection to the recording device. You obviously haven’t listened to my links. There are many KiwiSDR® receivers located on this map http://kiwisdr.com/public/ They are accessible from their links. Since Windows 11® and the internet can carry the older HE AAC® and the xHE AAC® they don’t have to be decoded and recoded into MP3 worsening the sound quality. DRM standard allows both the less efficient HE AAC and the new more efficient xHE AAC compression.
You could only call the https://www.skyworksinc.com/en/Products/Audio-and-Radio/Si4734-35-AM-FM-SW-LW-Radio-Receivers/Si4734 ‘low-IF architecture’ because that is what the manufacturer said. However, to make it easy I included a block diagram of the chip which showed the critical parts of an SDR receiver. The Analog to Digital Converter because Software will only work on a computer! This specialised computer runs programs to low pass filter the signal, demodulate the signal and digital to analog convert the signal to provide a signal for speakers. Even a check on Wikipedia would have shown you that! Digital radios, also COFDM demodulation, error correction and audio decompression. If it had been the older superheterodyne design there would have had to be a ceramic filter for the intermediate frequency which did not exist. SDR design is used in all mobile phones because you can tune a wide range of frequencies and any interference is inaudible because the frequencies are beyond the hearing range. Also there are no coils of physical filters making it possible to make a radio in a chip. This is why it is used on the reviewed radios on this site. It makes wide frequency range radios cheaper to manufacture because the radio itself is only one chip with few extra components other than a crystal to give accurate tuning. A photo of the DRM1000 printed circuit board shows not ceramic filters.
To complain about distortion when compared to the use of AM is a joke. The reception of multiple reflected signals from the ionosphere causes distortion and phasing, which is error corrected in DRM to produce distortion and noise free sound in the presence of multipath signals sounds great.
You lack of a simple check would find that Tim Davie in USA terms is a Chief Executive Officer who is also Chairs the board. https://www.bbc.com/aboutthebbc/whoweare/tim-davie What he says goes!
DRM is capable of operating in all frequency bands used by broadcasters now, including band 1 which is now vacant in North America. FCC regulation bans domestic High Frequency broadcasting which is just one reason why USA digital radio standards do not include these frequencies.
> This is just another post from a long and never ending campaign against a new technology
Posting my opinion is not a campaign. DRM is not a new technology, it’s from early 2000s – as new as Windows XP.
> Your campaign is based on Internet trawling instead of listening to real signals on real radios.
I have repeatedly said I did listen to various DRM broadcasts over-the-air, so kindly please stop making this kind of ad personam remarks.
> ‘DREAM’ software is not from the inventors
Which software comes from the inventors? Did they make one?
> (link)This software will give the best sound.
Doesn’t matter in the end because the transmitted audio is still more compressed than a phone call. Independent tests conducted by HydrogenAudio forum members (google i.e. “Personal Listening Test of AAC-LC and xHE-AAC at 96kbps and 128kbps”) show that xHE-AAC codec delivers only “perceptible, but not annoying” sound with 96 kbps. DRM offers max. 30 kbps which is nowhere near the transparency rate even for the latest codecs. A massive upgrade would have been needed for DRM even to match the quality of a modern phone call, but that didn’t happen, it’s still the same as 2 decades ago. They only changed the audio encoder but that’s akin to changing a light bulb in a car that’s all rusty – not going to help much.
> You could only call the Si4734 ‘low-IF architecture’ because that is what the manufacturer said.
Exactly. The manufacturer also did not claim it is an helicopter. It doesn’t make it want to fly, though.
I am going to stop the discussion about radio receiver designs there because it seems like a recurring pattern. For instance, I can see that similar claims about all radios supposedly being SDRs, based solely on the presence of ceramic IF filters, were brought in the comments to the “Soldersmoke: Mattia Zamana’s Amazing Direct Conversion Receiver” article in Oct 2023. The user Ron F has outlined and rectified these technical issues better than I possibly could. Finally, the topic of the article is the relevance of shortwave broadcasting in countering censorship and informational gaps, so I don’t think that examination of different RF designs falls in its scope.
> To complain about distortion when compared to the use of AM is a joke. The reception of multiple reflected signals from the ionosphere causes distortion and phasing
Which ones are present on the recording of the Australian station I posted?
> You lack of a simple check would find that Tim Davie in USA terms is a Chief Executive Officer who is also Chairs the board. https://www.bbc.com/aboutthebbc/whoweare/tim-davie What he says goes!
This is wrong on so many levels. The BBC is not a private company. There are multiple regulations that it must abide, for instance: its Royal Charter; The Agreement between the Secretary of State for Culture, Media and Sport and the BBC; OFCOM’s Operating Framework for the BBC etc. None of these can be altered single-handedly by Tim Davie. The fact that the BBC did not adapt a policy of “going all digital” is just another proof of that. If you claim otherwise, you should bring up verifiable proofs – decisions that have been adopted in an established process. I’m afraid just calling me names won’t make it more credible.
Most shortwave broadcasting is not anti-establishment. A lot of it is mainsteam dribble and not worth listening to unless it directly affects the recipient.
Not really much of anything new here.
I would bet the people in charge of shortwave broadcasting in most countries have never even listened to a shortwave broadcast; this would be due to a combination of factors, such as urban living, connective access to newer media and budgetary restraints. No personal relationship, no professional relationship.
I cannot argue that statement. It’s rather like, it’s not important to them, or others of their social class,, so it must not be important to anyone else. And generally, those in charge, seem to think they know best how others should live.
Another article that claims Russia has “significantly increased its global shortwave radio broadcasting efforts”. This is completely false. They do not broadcast on shortwave AT ALL! The SWLing Post, being a professional outlet, should not relay this sort of fake news.
Correct. ARK is incorrect about this Russia statement. Thanks for pointing it out.
Oh, and thanks for calling the SWLing Post a professional outlet.
I’m just a guy running a blog with a massive community of contributors.
But this is precisely the reason why it’s professional – in terms of fact-checking it can provide. Both the editor(s) and contributors have first-hand experience of using the medium. We know what’s happening on the bands. I may not have memorized all the schedules, but I know that Russia ceased SW broadcasting in 2014 and never returned since then. Don’t get me wrong – I do second most of the author’s arguments and I also think shortwave may be a vital resource. I also think that it’s good that such pieces are surfacing from time to time. But my point is that if someone’s trying to make a case for shortwave, the arguments must be factual, otherwise all the credibility is going to be ruined the moment reader tries to find out i.e. what’s the content of (in that case) the Russian broadcasts that are supposed to be transmitted everywhere and learns that in fact, there is nothing to be heard.
But China, on the other hand, is on 24/7 across all the bands, in a variety of languages.