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:

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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High-Frequency Trading Service: FCC posts two lobbying documents by DPA Mac

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Many thanks to SWLing Post contributor, Benn Kobb (AK4AV), who notes that the FCC has posted for public inspection two lobbying documents by DPA Mac, applicant for a new DRM HF broadcast station with 2 kW of transmitter output power.

Benn notes:

“Regardless of DPA’s claims that its broadcasts will be free of charge and not encrypted, its non-broadcast high-frequency trading service will be for paying customers only.

“That is the purpose of this station and is why its target areas, as seen in a world map slide, are limited to the location of certain foreign exchanges. This despite its claim to be a worldwide service.

“There is little profit in SW broadcasting today, and what business there is available is accommodated by those existing US HF stations that can hang on through economic shifts. No, the DPA Mac station is not devoted to global information as a business venture. It wants a license to provide private telecommunications. The broadcasts to the public are just so it can get licensed, because there is no other radio service in the HF spectrum for private international data links.

“At this time no one knows what the FCC will do with this license application and two other similar applications. What is clear is that the applicants want to get on the air ASAP before any possible changes that may affect the HF broadcasting service.”

The FCC posted the following documents in an accessible place on their website yesterday morning:

https://www.fcc.gov/ecfs/document/1110171119378/1

https://www.fcc.gov/ecfs/document/1110171119378/2

Thank you for the update, Benn.

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Has WTWW left shortwave?

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I recently learned from a few reports on Twitter that WTWW left shortwave for good on November 9, 2022 and will now only broadcast over the internet. I missed this announcement on the air and WTWW’s website doesn’t seem to reflect this information yet.

The WTWW wikipedia page has already been updated, however, with WTWW’s services noted in the past tense and the following addition was made this week:

On November 9, 2022, WTWW announced it would discontinue all shortwave operations, with intent to continue streaming the programming as long as it was feasible. Ted Randall cited a massive increase in transmitter usage fees (the majority of that being from electricity cost) that the station could not realistically pay. The station signed off for the last time that night, with its final programming including a farewell message from Randall encouraging listeners to continue listening to the Web stream, a string of listener requests from WTWW’s automated system, and the final song being a rendition of “America the Beautiful” by one of Randall’s favorite recording artists, Ronnie Milsap.

Can anyone confirm if WTWW has indeed stopped all shortwave transmitting? Please comment.

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Shortwave goes all chirpy chirpy, cheep cheep again

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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Readers and friends have spoken: I’m keeping the Sony ICF-SW100

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Yesterday, I published a post listing several radios for sale. These are all portables I haven’t used in a while–I would like them to be in the hands of someone who could put them on the air. I have so many portables that many get overlooked because I’m just one guy. That, and I’m also using the sales a means to build up my radio funds kitty for some future purchases.

In this first post, I mentioned I might sell my Sony ICF-SW100 and that I was on the fence.

Evidently you all know me better than I know me! I received 7 emails and numerous comments urging me to keep the SW100 noting that I would regret selling it.

I’m taking your advice and, frankly, I think you’re right: I believe I would regret this sale. It’s a unique radio and one I desperately wanted in the 1990s, but simply couldn’t afford. It works perfectly, too, so perhaps it’s a sign that I simply need to put it on the air more often.

Thank you for speaking up. I should note that the offers I received on the SW100 were all accompanied with notes telling me that I probably should keep it, too. That’s saying something!

I will be listing more radios here soon including:

A Uniden Bearcat TruckTracker V Scanner (BCD436HP) with GPS antenna
A Marathon ETFR with custom belt case
And possibly one of my Sony ICF-SW7600GRs as I have a total of three

I’ll have even more than this as I work through some of my extras. Stay tuned and thank you for the support!

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Thinning the herd at SWLing Post HQ

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I’m in the process of re-arranging my small office/radio shack and building a dedicated fold-out workbench for all of my projects that require a bit of solder and tinkering.

I need to downsize some of my radio collection to not only free up space but also re-fund the radio kitty. I literally have dozens and dozens of portables–many duplicates. I also don’t like radios to sit on a shelf–I’d rather them be in someone’s hands and on the air. There are a number of portables I use regularly and that I’m keeping for future performance comparisons.

Note that most of these radios are in a price class that likely makes international shipping a moot point (the shipping might cost as much as the radio). I’ve included shipping in the following prices, but this assumes USPS within the US.

If you’re interested in any of the following, contact me at: [email protected]

Also, please not that it could take time for me to reply to your inquiries due to my activities and travels this week.

Sony ICF-SW11 – Update: SOLD

This ICF-SW11 is in superb shape. Comes with original box and paperwork.
$65 shipped USPS to US.

Tivdio V-117 – Update: SOLD

This is a really simple analog display, DSP radio. Performance is respectable for such a super inexpensive radio. Of course, not a DXing machine or anything. $15 shipped USPS to US.

XHDATA D-808 – Update: SOLD

This is a wonderful DSP radio and I’ve had many a good listening session with this unit. If you’re not familiar with this radio, I highly recommend reading 13dka’s review. $90 shipped USPS to US.

Sony ICF-SW100 – Update: Keeping this one after all

I honestly can’t decide if I want to sell my SW-100. I swore I never would and I might change my mind. This one is not cosmetically perfect (perhaps 7 out of 10?)–I purchased it used from Universal Radio and had Vlado (N3CZ) replace the ribbon cable in this unit and tested it thoroughly in 2015. I have traveled extensively with this little radio since and it has served me well. I haven’t used it in ages, though, because as of late I tend to take my CC Skywave SSB or Belka DX since those would be easier to replace if damaged. This would only include the radio and the attachable cover. It works as it should and the battery cover is completely in tact.

If interested, just send me an offer. Full disclosure: I’m truly on the fence about this one and could change my mind.

More to come…

As I dig into my radio reserves, I may find others that I’ll post for sale.

And in case you’re wondering, I’m not leaving the world of shortwave. Not at all. Even after I sell of some extra units, I’ll still have 24 or more portables here. 🙂

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