Tag Archives: Digital Radio

FMX: Not all broadcast innovations come to fruition

Many thanks to SWLing Post contributor, Aaron Kuhn, who shares the following in-depth article from Tedium.com:

The story of FMX, the wannabe radio standard that was taken out in a very public way

Attempts at standard-building in the radio industry have come up repeatedly over the years, and few of them have stuck, not even in the nobody-knows-about-it way that AM stereo has made its mark.

Perhaps the most fascinating of these attempts to improve the radio signal, however, is that of FMX. Formulated in the late 1980s as a more pristine version of the FM dial, it intended to solve a major problem with FM that had been lingering since stereo had been added in the early 1960s: When you move to the edges of the coverage area, the sound quality gets really low.

As you can probably tell by the fact that it’s generally still a problem in many vehicles today, FMX failed to solve that problem.

But the reason why it failed to solve that problem is more complicated than saying it didn’t work. There were both technical and political issues at play.

The technology, for what it’s worth, did have the right folks supporting it: The brainchild of Tom Keller, an engineer with the National Association of Broadcasters, and Emil Torick, who worked in the same role for the CBS Technology Center, FMX was intended to fix stereo’s weaknesses in low-quality areas. The best part? It was backwards compatible. It would reduce noise and improve the fidelity of FM stations for stereos with upgraded equipment, but those with cheap beater radios would still have the same staticky-in-outlying-areas experience that they did before.

Paul Riismandel, a radio industry observer who co-founded the industry news outlet Radio Survivor, notes that the FMX technology wasn’t the first of its kind. For example, Dolby attempted to bring its noise-reduction technology, common in cassette tapes, to radio stations in the 1970s, but its offering was generally ignored due to the fact that proprietary equipment was needed. (Over at the Internet Archive is a sample of what Dolby FM sounded like during a 1978 Minnesota Public Radio broadcast.)

But FMX likely got further than most due to two factors that became apparent in the 1980s: The fuzziness of radio stations in fringe parts of the broadcast areas, and the pristine sounds of the compact disc, which was becoming popular at the time.

“FMX was a way for radio to compete with this new digital technology and adapt to listener expectations,” Riismandel noted.

But the FMX technology proved controversial within the radio industry due to two separate incidents that cost the technology its momentum.[…]

Read the full article on Tedium.com.

DigiFAQ Updated: An HF Digital Decoding primer and reference tool

Many thanks to SWLing Post contributor, Mike Agner, who writes:

[S]ome 20 years ago, Mike Chace-Ortiz, Stan Skalsky, myself and a bunch of other folks put together a FAQ about digital modes on radio – specifically modes going from LW way up into the UHF spectrum- called the DigiFAQ 5.3. I was responsible for the HF Software section, and as you might know, back then it was all about the hardware. InfoTech was still around, and amateur digital modes using the PK232 were plentiful. There is a PDF-based copy on the UDXF website [click here to download].

Now jump ahead 20 years or so, and things have changed considerably. Hardware is no longer king, and soundcard-driven software has taken over the market. Even receivers have changed – the desktops of old (quite apart from the current batch of ham transceivers that have general coverage radios built in) have been pretty much supplanted by Software Defined Radios. Along with that, the digital modes themselves have changed drastically with some disappearing altogether, with new ones like ALE going to the head of the pack. Too, the original DigiFAQ combined many ham-related modes along with everything else.

[O]ur original work didn’t really address some of the basic questions newcomers to this side of the hobby might have, [s]o with Mike Chace-Ortiz’s help, I have been involved in rewriting and updating the FAQ. Its approach is different – we start from topics like discussing radios, SDRs, some of the terminology you will see on mailing lists like the UDXF and much more. Only after we cover all of this do we discuss decoders – and even here, this topic is broken down even further, to include those decoders that play nice with some SDRs, and some of the tools you can use to help analyze an unknown signal.

Then we go into the modes (most are HF related, but we do touch on one or two common LW modes). We identify those modes that are dead, and separate them from the rarely used/active ones. Where possible we also supply waterfalls for each.

We also have an extensive appendix with a whole bunch of links for additional reading.

Perhaps of greatest use to newcomers is a listing of known scheduled broadcasts, so they can test what they download without wandering all over the place, hoping to find a readable signal – and potentially getting turned off when the don’t find one. We have also recovered a few articles from the old WUN archives as well as from SPEEDX (Society to Preserve the Engrossing Enjoyment of DXing – folded a long time ago) on certain digital related topics, such as discussing how to read an AMVER transmission.

It should be noted that we also sent the amateur radio digital modes to their own page for a very simple reason – while these modes are well understood (and many have their own devoted page that cover their mode far better than we can), the single biggest reason was that these modes can NEVER be encrypted (at least in the US, and likely other countries as well). Sad to say, but there are many modes outside of the amateur bands that we will never be able to read, and some whose purpose is unclear. As of this writing, many UDXF members are noting signals thought to be Russian in origin, utilizing a variation of MFSK-16, a mode generally associated with amateur radio.

Is this document complete? Not even close. It’s designed to be something of an introduction, with enough detail to hopefully draw in both the newcomer and experienced. There are new modes being identified, new networks, and even new players being found all the time. There’s still more work to be done on this, and this is yet another change to the original DigiFAQ- it’s hosted on the RadioReference wiki, where any member (with a free ID) can edit and add to it.

The URL is: http://wiki.radioreference.com/index.php/HF_Digital_Decoding

Regards, Mike

Thank you for sharing this update, Mike!

I receive a lot of questions regarding digital modes even though it’s an area of the hobby where I’m quite weak. I’m pleased that you, Mike, Stan and your team are all working to keep a reference source up-to-date for folks exploring this dynamic part of the radio hobby.

Click here to visit DigiFAQ at RadioReference.com.

Guest post: The future for radio broadcasting in Australia

Many thanks to SWLing Post contributor, Phil Brennan, who shares the following guest post–an article he originally authored for the Australian DX News:


WHKY-AM-Radio-Tower

What Future for Radio Broadcasting in Australia?

By Phil Brennan, Darwin, NT

As we witness the worldwide decline in long wave, medium wave , shortwave and indeed FM broadcasting, it can be at times a slightly depressing exercise to ponder the future of our hobby.  As I write, just last week Radio France announced that it will soon cease all LW broadcasting.  There’s an on-line petition to save the service: this morning it had collected 770 signatures after one week. It was 769 until I sent my modest click across the universe L.

On the domestic front we’ve seen the pointy-headed bean counters in Canberra and their political masters take the knife to our national broadcaster to the point where Radio Australia now seems to be little more than a relay station for the ABC with barely any in-house production tailored for its audience.

With all this doom and gloom it was with some trepidation that I spied a recent Australian Government report entitled Digital Radio Report [1] which arrived via my email in-box through the excellent Australian Policy On-line resource.  The report was published in July 2015 by the Department of Communications and was conducted by the Minister for Communications under the Broadcasting Services Act and the Radiocommunications Act. Note: the Minister for Communications then was Malcolm Turnbull who is now Australia’s Prime Minister.

The report makes for an interesting read (for nerds like us) and provides some great insight into the bureaucracy’s thinking on the future of radio broadcasting in this country.  So while the report ostensibly considers the current and potential state of digital radio in Australia, in so doing it looks at the other forms of radio broadcasting and gives us a peek into the future.

The report broadly considers the following issues:

  • The current state of digital broadcasting and alternative forms, eg streaming services through the interwebs
  • Whether Australia should set a digital switchover date and close off analogue services; and
  • The legal and regulatory framework for digital services.

Like you would have dear reader I quickly scrolled through the report to see if it was recommending a full switchover to digital.  The good news is that this won’t happen anytime soon and perhaps not ever.  Phew! It seems Australia’s geography and sparse population works in our favour (for once).  Anyway, more on that later.

So what does the Australian radio broadcasting landscape look like at present?  Well for lovers of analogue radio it’s still looking pretty strong and it’s likely to remain that way for some time to come.  In the five big cities the 2014 average weekly audience for commercial radio services grew by 4.13 per cent to 10.1 million people.  That’s pretty impressive given the quality of the stuff they serve up each day.  Aunty’s (that’s the ABC to foreign folk) radio service reached a record 4.7 million people in 13/14, an increase of 155,000 listeners on the previous year. Well done Aunty!

All up there are 273 analogue commercial radio services (104 on AM, 152 FM and 12 outside the broadcasting service bands.  Community radio is going strong with 357 analogue services (13 AM and 344 FM) plus 244 narrowcasters (33 AM and 211 FM).  There’s lots of stuff still out there it seems.  Perhaps too much as the FM band is becoming very crowded in the major metropolitan areas.

There are 142 commercial digital services in the big capitals plus the two trial sites in Canberra and Darwin.  Interestingly a good proportion of the digital services are simulcast analogue services, for example 11 out 29 of the commercial digitals in Sydney.  Listenership of digital radio is growing slowly and steadily, reaching 25 per cent in the first quarter of 2015, primarily due to the growth of receivers in motor vehicles.

Streaming services are rapidly gaining ground with services like Spotify, Pandora and the new Apple Music picking up new subscribers each week.  The move by Aunty and the Special Broadcasting Service’s (SBS) to mobile apps for streaming content is also showing good growth. It would appear that to some extent this growth has been at the expense of terrestrial digital services, but audience data in this area is pretty sketchy it seems.

So what of the future for digital radio? Well it seems that for the present the public does not show a preference for digital radio over other forms. And while some European countries such as Norway with near total digital coverage are looking to switch off their FM services, some countries such as the UK have postponed their planned switchover to digital due to slow uptake by the listening public.

In Australia there are big interests such as SBS, Commercial Radio Australia and Broadcast Australia pushing for a switchover to digital as soon as possible.   Thankfully the report’s authors have listened to other bodies that advocate for a multi technology approach.  Significantly the report notes that while digital could match FM for coverage with a similar number of transmitters, it will struggle to match the coverage provided by the medium and high powered AM transmitters that reach the remaining population.  Digital Radio Mondiale and satellite digital radio technologies could increase digital’s coverage but are not considered viable.

Internet based services are not seen as a realistic alternative in the medium term due to high data costs, restricted wifi coverage, likely interruptions in high traffic areas and poor battery life on mobiles.  It’s likely that this will be a niche medium for some time.

So what does the report conclude and recommend?  Well, digital radio was only ever introduced as a complimentary technology and that will continue to be the case.  In saying that the report makes a series of recommendations to free up the rules so broadcasters can take up the digital option more readily.  DAB+ is the preferred technology so don’t go ordering a DRM set anytime soon.

Perhaps most interestingly, the report makes a major finding that there may be an opportunity to consider how analogue terrestrial radio coverage can be improved pending the roll out of digital radio.  This includes further research into how AM coverage can be improved in metropolitan areas and whether the FM spectrum can be made available in regional areas for new analogue services or switching existing AM services over to FM, potentially in lieu of the rollout of digital services.  For us lovers of analogue radio this is certainly good news, particularly if more high powered AM broadcasters hit the band.

Does this actually mean that analogue radio services are safe?  Well, governments have been very good at ignoring reports advocating for the public good and succumbing to the commercial interests with other agendas, particularly when it comes to media.  That said, it doesn’t make a lot of sense for the government to pull the plug on analogue anytime soon given the coverage issues in regional Australia.  However, when it comes to governments, the sensible thing to do is often viewed as the last option.

[1] © Commonwealth of Australia


Thank you, Phil, for your article and opinions! I agree–in a country with such vast expanses, analog radio still has advantages over other mediums. Comments?

From Fessenden to HD Radio navigation

IBOC Spectrum (Source: GPS World)

IBOC Spectrum (Source: GPS World)

SWLing Post contributor, Richard Langley, is not only a dedicated shortwave DXer, but he’s also on the faculty of the Department of Geodesy and Geomatics Engineering at the University of New Brunswick. Additionally, Richard coordinates Innovation: a regular GPS World feature that discusses advances in GPS technology and its applications.

The latest Innovation feature is absolutely fascinating in that it highlights the potential for AM broadcast band HD radio signals (IBOC) to be an effective navigation aid. Richard’s introduction to this article takes us back to the time of Reginald Fessenden:

THE YEAR WAS 1906. On Christmas Eve of that year, Canadian inventor Reginald Fessenden carried out the first amplitude modulation (AM) radio broadcast of voice and music. He used a high-speed alternator capable of rotating at up to 20,000 revolutions per minute (rpm). Connected to an antenna circuit, it generated a continuous wave with a radio frequency equal to the product of the rotation speed and the number of magnetic rotor poles it had. With 360 poles, radio waves of up to about 100 kHz could be generated. However, Fessenden typically used a speed of 10,000 rpm to produce 60 kHz signals. By inserting a water-cooled microphone in the high-power antenna circuit, he amplitude-modulated the transmitted signal. On that Christmas Eve, he played phonograph records, spoke and played the violin with radio operators being amazed at what they heard.

Fessenden had earlier worked with spark-gap transmitters, as these were standard at the time for the transmission of Morse code, or telegraphy, the wireless communication method already in use. But they couldn’t generate a continuous wave and couldn’t produce satisfactory AM signals. But as telegraphy was the chief means of communication, they remained in use for many years along with high-powered alternators and the Poulsen arc transmitter, which could also generate continuous waves.

Continue reading at GPSworld.com…

In the UK, digital radio is not always well-received

DABMany thanks to my buddy, Dan, who shares this article from the Daily Mail:

“It was supposed to be the technology that would transform the way we listen to the radio.

But audiences condemned DAB – or Digital Audio Broadcasting – as a disaster yesterday because of the poor quality of the signal.

They complained that it cuts out in the middle of broadcasts, while others claim the technology is already out of date.

One even joked on Twitter that while we can now receive close-up photos of Pluto taken billions of miles away, he ‘still can’t get a good signal on DAB’.

DAB had been heralded as less prone to interference than AM or FM, but household appliances including microwave ovens, laptops, mobile phones and TVs have all been found to affect reception. Power lines and the weather can knock out digital signals, while signal strength can be reduced in built-up areas, in basements and inside buildings with thick stone or reinforced concrete walls.”

Read more: http://www.dailymail.co.uk/news/article-3168864/Coming-loud-clear-gripes-digital-radio-Audiences-condemn-DAB-poor-quality-signal-cuts-middle-programmes.html