Digital Radio Mondiale

 This is a re-post of an old web page from my now defunct g7ltt.com site.

DRM reception reports

It had to happen sooner or later. QSLing has finally come of age. In the world of DRM you can not only send your reception report to your favourite broadcaster but you can also email them screen shots of your reception!

Below are a collection of screen shots from the various DRM stations that I've received. They have all been received here at G7LTT in Randolph, NJ. 

CVC is a religious broadcaster from Australia. This broadcast was caught on a Saturday afternoon during the Rugby world Cup. It came from Moosbrunn in Austria and was aimed at the UK.

RCI's Sackville transmitter is my local DRM site. They sublet their airtime every day to other broadcasters such as Radio Sweden, Vatican etc.

I got this from DW's Sines transmitter in Portugal. Note that they are sending a Journaline text broadcast too.

This is DW's Journaline broadcast. The blue coloured headlines are actually web links which will open up the story in DReaM's mini web browser.

I got this one from Moosbrunn in Austria. Notice that there is no Journaline with this broadcast. this is unusual for DW.

This broadcast starts with the Call to Prayer. It comes direct from Kuwait and does very well here on the East Coast of the US.

In the DRM world these guys rock!! Not because they have lots of flashy stuff embedded in their data stream or because their programming is excellent (which it is!) but rather because they are a low power station running a mere 4KW. Yet despite their low power they are able to reach their target audience with a 100% decodeable signal. This broadcast was bagged whilst they were aiming their antenna towards Europe.

Unfortunately many SW stations don't seem to respect the fact that they share the bands with other broadcasters. In this picture we see an AM carrier right in the middle of the DRM carrier. The AM station clearly thought that the DRM noise was just that; noise. So they popped up their carrier thus trashing the DRM signal I was listening to. Click the picture to hear the result. The rushing noise is actually the data that would be the HCJB broadcast.

China Radio International comes from Radio Canada's Sackville site.  It's an English language service aimed at North America.

Radio Sweden is another Sackville client. Indeed they even mention during their sign-on that they are being broadcast from Radio Canada International's Sackville transmitter. I really like their magazine programme "60 Degrees North".

This is RFI's offering from Montsinery in the Caribbean. It was a special broadcast to the NAB show in Las Vegas which is held every April. It was actually aimed at the West Coast of the US but was very well received here in NJ. Despite the English speaking target audience it was in fact a French and Spanish language output.

RNW has a number of DRM outputs that reach us here in the US. This one was on 9800KHz from Sackville. They also have one from their Bonnaire station in the Caribbean. On good propagation days we can also get their 5865KHz output from Luxembourg.

Radio New Zealand International is a bit of a stretch for me. They must the the absolute farthest DRM station from my location. I can usually hear their carrier but can rarely decode their data. However, over on the West Coast they come crashing in.

Just like it says! I bagged this one directly from Italy on 11630KHz. Vatican radio are a major player in the DRM world. They have outputs on SW and MW all over the world. They are also a lessee on Radio Canada's Sackville transmitter.

This is another tough one for me. This is RFI's 1KW station on 3695KHz from Issodoun in France. It's a local French broadcast that seems to get out here to the East Coast very well at night. The tough part is that it's in the middle of the US 75 meter ham band. Both RFI and DW have an output in this band. I've heard many a comment from an ignorant ham operator complaining about the 10K wide "noise". They just ignore it an park their conversation on the top thus killing the DRM transmission stone dead.

Again, another tough one. This is Bayern RundFunk's news headlines output "B5 Aktuel" (B5 Notices). It's a 100W local output on 6085KHz. It's really only available when the band conditions are favourable. Note that they are sending some multi media as well as the audio stream. I was not able to get any better signal that this so couldn't decode the audio or multi media.

Another European capture. This one is from Radio Romania International (30KW Kvitsoy, Norway). Local broadcasters were to blame for me not getting the audio on this one also (3 green lights = full decode).

Damn those God bothering religious shortwave broadcasters! I had an S9+40db signal from Radio Prague (100KW Wofferton, UK) but couldn't decode much of it. Just 5kHz below them was one of my local God bothers prattling on about the book of Galations and he was spilling over his channel allotment something awful! So much for "love thy neighbour".  

Sometimes getting up early in the morning pays off. I bagged this Spanish broadcaster at 3:45 in the morning on 9730kHz. It appeared to be a current affairs programme but I'm not sure as my Spanish is about as good as my American.

I snagged this one totally at random. It's a 100kW signal from Woofferton in the UK. VT are one of the big players behind DRM and act as an airtime wholesaler. They own/manage a bunch of transmitters in the UK. This particular broadcast was on 9850kHz at 1230UTC. It was a relay of a Radio Taiwan Intl programme.

It [still] Buggers Other Channels

 A few years back I presented an essay at the SWLFest titled "Whatever Happened to Digital Radio?" The gist of it was that Digital Radio was already on the decline in the US having failed to gain any market traction. The story is the same worldwide on shortwave too. 

Unlike other markets around the globe the US uses a product from Ibiquity called In Band On Channel. Ibiquity has been bought and sold a few times since the release of IBOC. Its product name was made a little more friendly by the phrase "HD Radio" giving the illusion that the audio quality was superior to the existing traditional AM and FM systems

Over time the IBOC system gained the nickname "It Buggers Other Channels". It's easy to see why. Take a look at the below screenshot taken from my SDR software. I have an Afedri SDR-Net connected to a MLB-30 active loop antenna. I spotted this signal while looking for something else.

It's 30KHz wide!!  AM stations in the US are normally placed into a 10KHz slot. There is a vacant 10KHz slot either side of them (called "guard channels") which are usually reserved for stations in other markets thus allowing a kind of jigsaw puzzle whereby the various markets fit into each other without interference. 

So a signal 30KHz wide would invade both the guard channels on either side of the allotted frequency. The IBOC signal is injected in "wrapper" mode whereby the digital data is sent in 2 carriers either side of the main AM signal. In the above picture an AM carrier can clearly be seen in the right hand data bundle (the square thing to the right of the red line). Listeners to the station buried by the data signal will hear a rushing noise along with their normal station.

Perhaps this interference is why IBOC is on the decline? Its the same story on the FM band too. A scan of my local AM band (15 miles NW of Philly) reveals just 3 stations using IBOC down from 15 just a few years ago.

UPDATE: 20250925

A scan taken today of my local AM band shows my market is down to just 1 station sending out IBOC. That's drop of 2/3rds since this article was posted back in October 2024 (not quite 12 months)!