With digital music making a clean sweep in the 1990s over almost all listening media, it’s a surprise to find that there’s one area in which an analog hold-out is still very much alive and kicking. We’re talking not of a vinyl resurgence here but of FM radio, which has managed to effectively hold off its digital competition for a few decades now. Twenty years ago its days seemed numbered though, and in Europe the first generation of DAB digital radios looked ready to conquer the airwaves. Among them was a true oddity and one of Psion’s last significant consumer products, the WaveFinder USB DAB radio receiver. [Backofficeshow] has one, and has given it a teardown for our entertainment. He describes it as the first consumer SDR product which may be a little hyperbolic, but nevertheless, it’s an interesting look at what would become one of computing’s backwaters.
Inside the peak-90s-style translucent blue case is a single PCB with a lot of screening, on which sits a USB controller and a bunch of DSP chips. Radio demodulation was done in hardware, but signal demodulation was apparently done on the host PC. At the time its £299 price made it the affordable end of DAB reception, and The Register opined that its ability to download broadcast broadband data made it a revolutionary product, but sadly neither consumers nor broadcasters agreed and it was heavily discounted before making an ignominious exit. DAB itself would struggle to meet the expectations, and a multiplex-based licensing model for broadcasters making it unattractive to local stations means that even now FM is still full of stations. Perhaps as listening moves inexorably to streaming its time has passed, indeed Ireland has gone so far as to abandon DAB altogether.
If you’d like to know more about DAB, we took a look at the technology a while back.
Via [RTL-SDR]
1990s eh?
It looks like a prop from a B-grade 1950s Sci-fi movie.
Can’t comment on the video as I have YouTube blocked, but those DAB and DAB+ radios have a crazy amount of DSP going on. Far from “just” being commerical radio done with digital transmission techniques, it’s a full-on multiplexed system with several stations sharing a transmitter. The entire “channel” is about 2MHz wide… and is very susceptible to multi-path reception. Positioning a DAB+ antenna can feel a lot like pointing the rabbit ears on an old analogue television set.
I own exactly one DAB+ radio… a small portable unit that I bought earlier in the year. Nearly all my radio listening is using a RTL-SDR v3 dongle and a package called qt-dab. The portable unit is good when I’m away from home, but at home I just use the RTL-SDR.
There’s a good reason why FM wins: better audio quality (okay, depends on the station… but 4KQ before they shut down were broadcasting 24kHz 48kbps HE-AAC — so 12kHz Nyquist limit on the baseband, compared with FMs ~15kHz baseband bandwidth), and better robustness to signal drop-outs. Some stations broadcast with less: Triple M Classic Rock typically broadcasts at 32kbps… and one station (Coles TAS) broadcasts at 16kbps. (Music at 16kbps HE-AAC sounds F###ing awful!)
Where FM might get a bit of audible hiss, DAB+ drops in and out sharply. I hear DAB (which used MPEG2 audio compression, thus needed to use “softer” forward-error correction due to a higher bitrate being required for acceptable audio quality), sounds like “boiling mud” when the signal is poor. DAB+ stutters. One can usually tolerate a bit of background whitenoise, but a stuttery signal is unlistenable.
About the only place where DAB+ won was against AM radio… where it had both better audio quality and generally better robustness to interference. However, even there… AM will go the distance — sitting at my house in NW Brisbane, I can regularly pick up AM stations as far away as Emerald and Bundaberg.
If I get the right point in my room, I can get River 94.9 broadcasting from The Knobby outside Ipswich (which is odd, because VK4RAI shares the same tower, and I hear it and can work it loud-and-strong with a mere 20W — River 94.9 would be transmitting orders of magnitude more power).
The Brisbane DAB+ stations disappear if we head over the hill to Keperra (Enoggera hill is in the way)… and I can receive the DAB+ stations on the Bruce Highway maybe a few minutes past the Burpengary BP … then it drops out, and no amount of fiddling gain settings gets it back.
+1
What also was interesting was DRM, Dogital Radio Mondiale.
https://en.wikipedia.org/wiki/Digital_Radio_Mondiale
It had (still has) a decent audio quality over shortwave.
It’s not FM quality, but close to good AM, without the buzzy and humming sounds.
A free software, Dream, can be used to demodulate both DRM and AM with a simple SDR hardware.
That SDR often consists of soundcard and a direct conversion (DC) receiver with 7 to 12 KHz intermediate frequency (IF). 12 KHz is the recommended minimum IF.
Alternatively, any shortwave receiver can be used if the IF was internally tapped.
Even ancient receivers from the early 20th century.
The Dream software can compensate for slow drift, too.
https://www.elexs.de/ef956.htm
https://m.youtube.com/watch?v=Vo_q_UgwYC8
Another interesting technology WorldSpace Radio.
Too bad it wasn’t accepted worldwide.
By comparison, the receiver technology was mature and cheaply to produce.
The total contrast to DAB(+), which is still a luxury item in cars and won’t work properly at high speeds.
Ancient FM was more robust against doppler effect, also.
https://en.wikipedia.org/wiki/1worldspace
Yeah, DRM is a real head-scratcher… it can use MW bands as well, frequencies which we have in good supply here in Australia, but the ACMA decided to back DAB+ instead using ex-television VHF frequencies which are in higher demand for lots of applications.
I don’t explain the decisions made in Canberra.
ACMA are a bunch of drongos, more interested in auctioning off our spectrum than *using* it to serve the people. For example, shutting down 2G mobile, (and 3G soon apparently) crippling DAB with bandwidth and power limits, reselling old TV spectrum for “internet” … I could go on. Meanwhile right here in Canberra I still can’t get reliable broadband. Wired or wireless, they both suck.
Agreed, it was killed by stupidity. I mean, why go digital at a lower standard than the existing analog fm signal?
Most of the digital channels in Aus are about the same quality as AM – without the range or cheap receivers.. So digital was DESIGNED to fail, and fail it did.
Where DAB fell through was in the politics – basically just about everyone who could wanting to grab as much licensing fees/commercial rights/etc from it as possible, including reducing the audio quality to save bitrate for more channels to cram in even more channels. As a digital format it has the unfortunate property of having a sharp drop off, but since it requires orders of magnitude weaker signal to work (far beyond where an FM station would’ve been considered garbage), it’s a non problem. In face, her in Norway we cover _far_ greater areas with much more stations with less than 1/10 the transmission power (which translates to lower electric bill, installation cost and maintenance), and because interference isn’t destructive, adding coverage in a “radio valley” (like a tunnel, or behind any random mountain you’ll find over here), is fairly trivial.
Had all but forgotten how terrible FM was when being mobile (driving) until I went to Spain for a holiday, you can hardly drive more than 10-15 minutes listening to the same station. Drove up north for a holiday just before that (16+ hours driving), and had about 2-3 dropouts.
In the USA we have “HD Radio” and it’s TOTAL CRAP!!
The analog signal can be heard at 4X the distance.
Thanks FCC. :(
Actually iBiquity. Just the naming-ruse was bad enough. High Distortion, High Dropout, Huge Disappointment, High Deficit (public radio), and on and on. The Bush (R) administration gave them a 50% handout for each public radio station that had to sign on at a quarter million $ per transmitter.
What a waste of taxpayer money (NPR).
B^)
I first thought this is some kind of esoteric “analyzer” device from scientology or sth… Really weird looking thing for a radio…
I bought one of these from PCWorld for £20.00
Yes the software was garbage, it would work fine one day and then an absolute ball-ache the next day.
I did try the web-ever-dab and it was just a simple landing page, sort of an advanced teletext.
I think if the software was better, then sales might have improved, but if you can’t make it work they’re not going to sell.
I forgot to mention, I was looking for this on reddit, I though it was a creative labs product after all it’s their forte.
https://www.reddit.com/r/techsupport/comments/wj7744/pc_radio_receiver_circa_2000_please_help_me_find/
Very meta.
I finally decided to ditch my wavefinder a couple of weeks ago, I could not think of any practical use for it, period. I should have been more imaginative, is all else fails, do a year down!
Ps it hasn’t actually made it to the recyclers yet, should I put it on ebay instead?!
According to technicians of the TDF operator, the French public analog FM channels are screamed from PCM 48 kHz, 24 bits.
Many commercial FM are still from MP3.
Around here, DAB+ broadcasts AAC 88 kbit/s, terrible compared to the analog audio based on PCM, and better than analog based on MP3.
DAB+ is claimed to be energy efficient by the RF suppliers. One RF carrier broadcasts more than ten channels.
A TDF specialist moderates the argument. On the transmitter side, the RF quality required by DAB+ roughly doubles the power requirement.
The reciever side is another story. The batteries of my FM handheld last 30 hours. With the same batteries, the DAB+ version shouts up to 5 hours.
Globally, the digital mode consumes around 4 times the energy of FM.
The energy comparison with cellular streaming is hard, because the cellular infrastructure is shared by other applications. With the same batteries, my smartphone would play 4 hours.
Yes – I remember DAB Radio, at least here in Germany ;-)
The popularity of DAB seems to vary quite widely between countries.
Our three cars all have a DAB+ tuner, and most of the time we actually listen to programs via DAB+ (when not CarPlay Streaming). It’s FM that’s dead here, at least in cars.
HiFi listening @home of course is a completely different animal.