Category Archives: Digital Modes

Guest Post: Review of an affordable, compact DAB+ portable radio

Many thanks to SWLing Post contributor, Mangosman, who shares the following review:


DAB+ digital audio/FM receiver and Bluetooth Audio Player with 2.4 inch LCD Display 

by Mangosman

Digital Audio Broadcasting with improved audio compression and error correction is called DAB+. I have had this radio for a few years.

Retail in Australia DAB+/FM radios are generally double the price and more. There has only been one model of DAB+/FM/AM radios which is now no longer trading.

This is a size comparison, the sound is very clear and is surprisingly good on music as well, despite having such a small speaker. Even at maximum volume there is no audible noise or distortion. The stereo program HE AAC compressed and FM and Bluetooth and is available on cabled headphones. Such a small speaker cannot produce much in the way of bass, but it is present on headphones.  Since DAB+ is a pure digital system, there is, full stereo, no noise as the radiated signal deteriorates, until the receiver mutes when error correction fails. The radio has a 400 mm long telescopic antenna.

On FM this receiver will decode Radio Data System data, I have had more sensitive FM reception.

This is the most sensitive DAB+ receiver I have owned. I am also currently also using two BUSH clock radios. I also have used older headphone radios, but push buttons and headphone sockets haven’t been very reliable.

This screen shows a full  colour album cover which can fill the screen and title. Smooth FM is the broadcaster’s name because it is simulcast in some other cities on FM and DAB+. The indicators on this screen are level of battery change, muting, stereo indicator, when decoded and the signal strength. Continue reading

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DRM Test Broadcast on 954 kHz in the Czech Republic

DRM Test Broadcast on 954 kHz from Transmitter in Czech Republic (DRM Consortium)

DRM is now on air in the Czech Republic, on a medium wave channel that used to carry a powerful AM signal. It is broadcast on 954kHz (power reported as 3kW) from the ?eské Bud?jovice transmitter site, located in the South Bohemian region re-using the old AM antenna with a modulator connected to the existing 30 kW AM transmitter.

The DRM transmission on 954kHz was even received in the country using a KiwiSDR.

This is a trial of DRM within the Czech Republic and is scheduled to come to an end possibly in the second half of 2023. The content is supplied by Radiožurnal, a news and journalism station that broadcasts 24 hours a day covering events at home and abroad. The station also carries music in between the news segments.

One of the listeners receiving the DRM signal in the country reported: “From my listening on the remote receivers, it seems to me that a few low-powered AM transmitters could cover the whole country”. [Click here to read the original article…]

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SSTV Fiesta 2022

Many thanks to SWLing Post contributor, Mario Filippi (N2HUN), who writes:

For those who’d like to try receiving SSTV images and also get into the holiday spirit, there is an annual SSTV Fiesta from December 12, 2022 to January 6, 2023. The Fiesta is sponsored by the Azteca DX’ers. The frequencies are 14.230 MHz in the 20m amateur band and 27.700 MHz, just above the US Citizen’s Band.

An excellent decoder is MMSSTV available free on line.

I’ve monitored 27.700 MHz the past week and have decoded the images below using an Airspy HF + Discovery, 31 foot ground mounted vertical, MMSSTV software and VB cable for piping the audio from the Airspy to MMSSTV.

Note that you have to set your receiver to USB. With MMSSTV you can set your receiver on the frequency of choice and just walk away like I did and the software will store any images received. Image clarity depends on propagation, just like other modes.

Good luck, thanks go out to the Azteca DX’ers for this enjoyable event and 73’s.

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Radio Waves: Colombia’s life-saving pop song, FCC Commissioner Pro AM Radio, Experimental Radio News 6, FCC Comments on FM Power Increase, and Leo Laporte Retires

Radio Waves:  Stories Making Waves in the World of Radio

Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!


Colombia’s life-saving pop song (BBC Sounds)

It is 2010 and Colombian Colonel Jose Espejo has a problem. Not only is the Farc increasing its kidnapping activity, targeting police and military hostages, but many of the soldiers already in captivity – some kept in barbed-wire cages and held isolation in for over a decade – are losing hope of ever being rescued.

Colombia’s dense jungle and mountainous terrain mean rescue missions can take months to plan, especially because Farc guerrillas are known to shoot all hostages dead at the first hint of a raid. Colonel Espejo knew that in order for future missions to succeed, he would need to warn the captives that help was coming so they could be ready to make a break for it when the army arrived. But how do you get a message across to military hostages without tipping off their captors and placing them in even greater danger?

The unexpected solution – hide the message in a pop song with an interlude in Morse code that the military hostages could decipher. Soldiers learned Morse code in basic training, and it was unlikely that the Farc, who were not military trained, would know it. This is the tale of Better Days, a pop song with a secret Morse code message that became an actual lifesaver.

Click here to listen to this program on BBC Sounds.

FCC Commissioner Advocates for Preservation of AM Radio (Radio World)

At the NAFB Convention, Simington said AM radio is an “indispensable resource”

FCC Commissioner Nathan Simington met with members of the National Association of Farm Broadcasting during their 79th annual convention on Nov. 16. In his remarks, Simington emphasized the importance of AM radio and outlined the steps needed to ensure its future in a changing market.

Simington began his remarks with a more personal anecdote. He said he grew up on a farm in Saskatchewan, Canada, where “besides the trade papers, there was no media institution more trusted to inform us about all we needed to know than AM radio.”

“AM radio was for us then, and is for the more than three million farmers across the U.S. now, an indispensable resource,” he said.

Simington said AM radio is the “essential spine” of the Emergency Alert System and “lets you know what’s happening not just globally, but locally — from school closures and traffic delays to city council and county management meetings and high school sports games.”

He comments on the growing populations that view AM radio as a “dead” and outdated technology, and why he believes that to be a falsity. [Continue reading…]

Experimental Radio News 6

This issue is devoted entirely to experimental high-frequency (HF) or shortwave radio, including a new FCC docket accepting comments on a license application.

Click here to check out the latest Experimental Radio News issue!

Continue reading

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Guest Post: Monitoring Digital Selective Calling (DCS) with YADD

Many thanks to SWLing Post contributor, Don Moore–noted author, traveler, and DXer–for the following guest post:


Photo by Borderpolar Photographer

Monitoring DSC with YADD

By Don Moore

(The following article was originally published in the April/May 2022 edition of the Great Lakes Monitor, bulletin of the Michigan Association of Radio Enthusiasts. An all-band listening club, MARE publishes a bi-monthly print bulletin and a weekly e-mail loggings tip-sheet. The club also holds regular get-togethers, picnics, and DXpeditions, generally in southeastern Michigan.)

There are dozens if not hundreds of different digital modes used for communication on the MF and HF bands. These aren’t broadcasts you want to listen to unless you like to hear weird tones, beeps, warbles, and grinding noises interspersed with static. Digital modes are for monitoring, not listening. And monitoring them requires having software that does the listening for you and converts the noises into something meaningful – like the ID of the station you’re tuned to. The learning curve to DXing digital utilities can be steep. There are lots of modes to identify and the software can be complicated to learn. Some broadcasts are encrypted so you can’t decode them no matter how hard you try. But the reward is lots of new stations and even new countries that you wouldn’t be able to add to your logbook otherwise.

One of the easiest digital modes to DX is DSC, or Digital Selective Calling. DSC is a defined as “a standard for transmitting pre-defined digital messages.” Look online if you want to understand the technical specifications that specify the values, placement, and spacing of the tones. The result of those specifications is a string of three-digit numbers like this:

125 107 125 106 120 105 120 104 000 120 022 120 041 000 002 022 020 041 108 002 053 020 080 108 006 053 021 080 070 006 118 021 126 070 126 118 126 126 126 126 126 126 126 126 126 126 117 126 112 126 117 117 117 112 109 125 108 125

Each three-digit value represents either a digit or a key word and the positions of the values map to the various fields contained in the message. This message, which was received on 8414.5 kHz, is a test call from the tanker Brook Trout to the coastal station Coruña Radio in Spain. The sender and destination are not identified by name but rather by their nine-digit MMSI (Maritime Mobile Service Identity) numbers – 538006217 for the vessel and 002241022 for the coastal station.

GETTING STARTED WITH DSC

Logging DSC stations requires three pieces of software. First you need a decoder program that turns the noises into numbers and the numbers into meaning. There are several free and commercial options but the most popular one for beginners is YADD – Yet Another DSC Decoder. YADD is free and easy to set up and while YADD can be used by feeding the audio from a traditional radio into your computer, the most common use is with an SDR. That’s what I use and what I will describe here.

Second you need an SDR application and an SDR. I prefer HDSDR for most of my SDR use but I like SDR-Console for digital work. But any SDR program will work if you can feed the audio to a virtual audio cable. And that’s the final thing you need – a virtual audio cable to create a direct audio connection between your SDR application and YADD. There are several different ones available but I recommend VB-Cable. Your first VB-Cable is free and that is all you need to run a single instance of YADD. If you want to expand you can buy up to four more cables from them later. Continue reading

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Radio Waves: Antenna ID, DRM Receiver Requirements Revisited, BBC Broadcasting Technology, and Digital Sound Broadcasting Framework in Kenya

Radio Waves:  Stories Making Waves in the World of Radio

Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!


Identify that antenna by sight (Hackaday)

It’s a skill that radio amateurs pick up over years but which it sometimes comes as a surprise to find that is not shared by everyone, the ability to casually glance at an antenna on a mast or a rooftop and guess what it might be used for. By which of course I mean not some intuitive ability to mentally decode radio signals from thin air, but most of us can look at a given antenna and immediately glean a lot of information about its frequency and performance. Is this privileged knowledge handed down from the Elmers at the secret ceremony of conferring a radio amateur’s licence upon a baby ham? Not at all, in fact stick around, and I’ll share some of the tricks. [Continue reading…]

Minimum Receiver Requirement Document Revisited (DRM Consortium)

The latest version of the document (mrr.drm.org) describes the DRM (Digital Radio Mondiale) receiver characteristics for consumer equipment intended for terrestrial reception operating in the frequency bands below 30 MHz (i.e. DRM robustness modes A to D) and also those for the frequency bands above 30 MHz (i.e. DRM robustness mode E). The goals of the document are to: provide guidelines to receiver manufacturers for minimum receiver performance and technical features, to offer confidence to broadcasters that their DRM transmission can be received by all receivers in the market, to assist broadcasters to plan their network and to give full confidence to consumers that all important DRM features are supported by receivers and all DRM transmissions can be received when they acquire a digital DRM receiver.

Click here to download (PDF).

BBC broadcast tech: then and now (Engineering and Technology)

In its centenary year, we look at the BBC’s pivotal role in making the broadcast and radio technology field what it is today.

Daily London broadcasts by the newly formed British Broadcasting Company began from Marconi House on The Strand, on 14 November 1922, using the call sign 2LO, with transmissions from Birmingham and Manchester starting on the following day.

The first broadcast by the young company, which was heard as grainy, muffled speech, was read by Arthur Burrows, who joined the BBC as director of programmes. Notably, he was one of the first people to move from newspaper to broadcast reporting.

At the end of 1922, Scottish engineer John Reith, who was just 33 years old at the time, was appointed general manager of the BBC, which then had a staff of four. Reith is remembered for establishing the tradition of independent public service broadcasting in the United Kingdom.

Within months, the growing organisation moved into the same building as the Institution of Electrical Engineers at Savoy Hill (now the IET’s Savoy Place event venue), where it continued to expand. This was an obvious home for the young BBC, and for the next nine years this is where early innovations of broadcasting occurred.

The British Broadcasting Corporation, as it is known today, was established in January 1927 as a public corporation, and in 1934 it moved from Savoy Hill to the purpose-built Broadcasting House in Portland Place. [Continue reading…]

CA plans digital radio shift on shortage of frequencies (Business Daily Africa)

Kenyan broadcasters will be allowed to adopt a new digital radio standard, which will enable them to use their current spectrum to transmit their signals through a digital network, as the sector regulator moves to address the shortage of analogue frequencies.

The Communications Authority of Kenya (CA) has called for stakeholder and public views on a draft Digital Sound Broadcasting (DSB) framework it has formulated to ensure the efficient use of the available broadcasting spectrum and encourage investment in the sub-sector.

“The objective of this consultation is to develop a suitable framework for Digital Sound Broadcasting in Kenya to address the challenge of high demand and low availability for analogue FM broadcasting frequencies that is currently being experienced,” said the CA. [Continue reading…]


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