April 12 2024

MHz Block UTC ITU Ensemble + Location Details Remarks km
176.64 5B 0522 BEL NAM-LUX 1, La Roche-en-Ardenne DAB 108km
195.94 8A 0524 BEL Ostbelgien 8A, Amel/Meyerode (wal-lge) 128km
190.64 7B 0529 D hr Radio, Sackpfeife (Biedenkopf) (hes) 267km
190.64 7B 0534 D hr Radio, Hohe Wurzel (hes) 261km
185.36 6C 0551 BEL NAM-LUX 2, La Roche-en-Ardenne DAB 108km
202.93 9A 0558 D DR Saarland, Felsberg-Berus (saa) 237km
190.64 7B 0614 D hr Radio, Rimberg (hes) 333km
199.36 8C 0626 F Métropolitain 2, Le Touquet-Paris-Plage/Lefaux (62) 221km
176.64 5B 0644 BEL NAM-LUX 1, Arlon/Route de Bastogne (wal-lux) 165km
176.64 5B 0644 BEL NAM-LUX 1, Bouillon/Route du Moulin (wal-lux) 138km
197.65 8B 0712 F Métropolitain 2, Metz/Fort Diou (57) 232km
197.65 8B 0712 F Métropolitain 2, Thionville/Oetringer Seite (57) 203km
204.64 9B 0713 D Antenne DE, Saarbrücken/Schoksberg (saa) 246km
218.64 11B 0750 D OAS BW, Heidelberg/Königstuhl, SWR (bwü) 336km
204.64 9B 1755 D Antenne DE, Bornberg (rlp) 257km

Map

April 5 2024 – Qt-DAB-6.X released

Jan Van Katwijk has released Qt-DAB-6.X. As always there are different version of this software.
Download Qt-DAB here.

What’s new in Qt-DAB-6.X?
First of all there’s the dx display widget showing all received TTI’s and transmitter info.
The size and position are retained for the next Qt session. The strongest received location is at the top with a *** marker.

dx display and ncp

How to activate the dx display widget?
1. Activate the Configuration and control widget and
2. check DX.
3. The dx display widget pops up showing all received TII locations, distances, azimuth and transmitter heights
4. with the strongest location (***) at the top.

If the user chooses NOT to use the dx display widget Qt-DAB then only shows the strongest received transmitter/location in the main widget.

dx display off

Also new is the option to select the ncp in the spectrumscope widget (5). The constellation diagram of the decoded carriers is shown.

What else?
A selection between portaudio and Xmultimedia as “output driver”. Check the configuration widget.
When there’s no station slideshow a slideshow with computer images from Jan’s youth.

If you have a decent antenna splitter and two devices you can of course hook up e.g. QIRX to one device and Qt to another. So you can show TTI info from the same mux at the same time from two different sources.

QIRX and Qt TTI in one screen

March 22 2024

MHz Block UTC ITU Ensemble + Location Details Remarks km
188.93 7A 0656 F Valenciennes, Cambrai/Martin-Martine (59) 138km
197.65 8B 0656 F Métropolitain 1, Combles/A1 rue de Sailly (80) 170km
199.36 8C 0657 F Métropolitain 2, Saint-Omer/route D210E2 (62) 176km
197.65 8B 0702 F Métropolitain 1, Calais/Résidence des Pélicans (62) 198km
197.65 8B 0709 D NI OSNABRCK K8B, Osnabrück/Schleptruper Egge (nds) 275km
204.64 9B 0711 D Antenne DE, Siegen Süd (nrw) 233km
208.06 9D 0712 D Mein NRW DAB+, Ebbegebirge Herscheid (nrw) 214km

Map

March 13 2024

MHz Block UTC ITU Ensemble + Location Details Remarks km
197.65 8B 1412 F Métropolitain 1, Abbeville-Mareuil 2 (80) 229km
197.65 8B 1414 F Métropolitain 1, Boulogne-sur-Mer/Mont Lambert (62) 217km
199.36 8C 1415 F Métropolitain 2, Saint-Omer/route D210E2 (62) 176km
199.36 8C 1417 F Métropolitain 2, Pont-Audemer/le Bel Air (27) 352km TII collision with Abbeville?
197.65 8B 1444 F Métropolitain 1, Calais/Résidence des Pélicans (62) 198km
197.65 8B 1444 F Métropolitain 1, Combles/A1 rue de Sailly (80) 170km
197.65 8B 1445 F Métropolitain 1, Abbeville-Mareuil 2 (80) 229km
197.65 8B 1632 F Métropolitain 1, Le Touquet-Paris-Plage/Lefaux (62) 221km TTI collision with Douai?
19.36 8C 1643 F Métropolitain 2, Creil/Mont Pagnotte (60) 241km

Map

March 5 2024 – splitter

When comparing different DAB (or FM a.o.) receiving devices it’s helpful to connect them all to the same antenna at the same time making it easy to switch between devices.
It did so when testing different SDR devices on DAB.
I had a few splitters lying about and after some comparing the Keliiyo 4-way coaxial splitter produced the best results, i.e. had the least loss numbers.
So I decided to compare the CNR numbers with the antennas hooked up directly to my RSPdx and hooked up via the splitter. Measurements were done on very strong local muxes to avoid too much fluctuations.
The results were rather surprising showing a lot less loss than expected when using this splitter.
Make sure you have a power pass splitter when using a LNA (with BIAS-T).
What to do when there’s great tropo? Using a splitter will be ok, but then again I’d like to squeeze every drop of DX out of a lift … so I will then hook up my antennas to the device in use without a splitter.

Keliiyo in numbers
Keliiyo splitter
Kaliiyo splitter set-up

March 1 2024

MHz Block UTC ITU Ensemble + Location Details Remarks km
199.36 8C 0659 F Métropolitain 2, Saint-Omer/route D210E2 (62) 176km
197.65 8B 0700 F Métropolitain 1, Béthune/Fresnicourt-le-Dolmen (62) 161km
197.65 8B 0700 F Métropolitain 1, Combles/A1 rue de Sailly (80) 170km
208.06 9D 0711 D Mein NRW DAB+, Ebbegebirge Herscheid (nrw) 214km

Map

February 24 2024 – three devices on DAB

On February 7 2024 I got my new toy: an RSPdx.
As I already owned an RTL-SDRV4 and an RSP1A I wondered how this RSPdx would perform on DAB compared to the trusted RTL-SDRV4 and the RSP1A.
I also own an RTL-SDRV3. On DAB V3 and V4 perform the same in my experience.

Time to do some testing. As the RTL-SDRV4 performs well on DAB vs the other devices, but is outperformed on FM and HF. My AirspyR2 and the RSP1A/RSPdx do a lot better than the RTL-SDR and have of course a wider spectrum to view on OIRT/CCIR/HF. So I decided to concentrate on DAB only.
The SRDplay data sheet tells a few things about the RSPdx performance on DAB.

  • Effective blocking of WFM (its “notch” filter), 85-107MHz >50dB attenuation, SW switchable
  • Bandwidth ideal for DAB, 1536MHz
  • High stability TCXO (0.5ppm)
  • For the other bands, a DAB notch filter between 155-235MHz, blocking DAB effectively (>20/30dB)
  • A number of bandpass filters, covering also the DAB range (120-250MHz)

What was the set-up for this test?
An antenna splitter fed antennas to the RSPdx to my desktop pc and to the RSP1A to my laptop. (Schematics).
Cables and devices were switched between the desktop and laptop, but that didn’t make a difference at all. The software I used for both devices and on both computers was QIRX 4.2.1.
Qt-DAB would also have been an option, but I didn’t want this test to become too cluttered and unnecessarily complicated.

How was the test run?
A first run was between RSPdx and RTL-SDRV4. Each tested MUX was run simultaneously and logged on both computers for the same time period and the average CNR (dB) and MER (dB) values were calculated.
A second run was between RSPdx and RSP1A with the same procedure. I noticed that a visual and simultaneous short comparison also produced the same values.
I did not check for audio drop-outs as this might a bit tricky to register on two computers at the same time.

Results?

  1. Comparing CNR (dB) between RSPdx and RTL-SDRV4.
    Values for RTL-SDRV4 are slightly higher: on average a mere 0.2 dB.
  2. Comparing MER (dB) between RSPdx and RTL-SDRV4.
    Values for RTL-SDRV4 are slightly higher: on average a mere 0.4 dB.
  3. Comparing CNR (dB) between RSPdx and RSP1A.
    Values for RSP1A are slightly higher: on average a mere 0.5 dB.
  4. Comparing MER (dB) between RSPdx and RSP1A.
    Values for RSP1A are slightly higher: on average a mere 0.2 dB.

As can be concluded from these numbers the differences between all three devices in CNR and MER are almost nil. In only a few instances RTL-SDRV4 or RSP1A detected data where RSPdx didn’t … initially.

RTL-SDRV4 CNR vs RSPdx CNR
RTL-SDRV4 MER vs RSPdx MER
RSPdx CNR vs RSP1A CNR
RSPdx MER vs RSP1A MER

Results in numbers.

Evaluation

1. RTL-SDRV4

  • The RTL-SDRV4 is a relatively cheap device costing about 60 euros. Do mind that the first batch of the RL-SDRV4 had a non-functioning HW AGC. Do check out this page on RTL-SDRV4 drivers.
  • As can be seen in the numbers crunched above the RTL-SDRV4 performs excellently on DAB.
    If you are only interested in DAB, this device will not disappoint you.
  • However if you are also into FMDX (small spectrum width) and HF RTL-SDRV4 should be considered to be of entry level. The WRTH 2024 has an informative article on ‘SDR for Beginners: RTL-SDR’ by Oliver Schmidt .
  • Setting up this device in QIRX is pretty easy.
    Make sure the Bandwidth (frontend, tab R828D) is set to 1.540 kHz or even up to 1.700 kHz.
    AGC is on, but of course you can manually set the Gain. The AGC Selector currently has to be set to SW, due to a HW bug.
    Don’t forget to activate the Bias-T when using a LNA like the RTL-SDR Blog T.
    You only need to do this once as QIRX will remember the settings.

Tip: when considering to buy a RTL-SDRV4 you might want to spend a bit more and purchase the set with dipole antenna kit, which comes in handy when doing some DX on the move.

2. RSP1A

  • RPS1A is a great device and it performs well not only on DAB, but also on FM an HF.
    You can buy an RSP1A device for about 125 euros.
  • Performance on DAB is excellent, almost of the same level as a RTL-SDRV4 as shown in the test results.
  • Setting up RSP1A needs some attention. The user can block DAB and WFM but this setting is not retained for the next session. Surely this will be adjusted in a future QIRX update.
    The spectrum width can be set up to a nice about 8 MHz (Select 8192000 Sampling Rate in the QIRX Settings, Sampling Rate). However my old laptop tends to crash with these settings.
    There is no ‘DX’ advantage in setting a higher sampling rate though.
    As with the RTL-SDRV4 the user can set the AGC on or off and this setting is retained.
    All RSPs feature an excellent HW-driven AGC, sadly not including the LNA State.
    The Bias-T on/off setting is retained too.
  • Don’t forget to check and adjust the LNA State as this can prevent overload.
  • A correct LNA State can improve reception and often makes a difference between a nice signal or nothing at all! While DXing with RSP1A the user will need to do some fiddling with LNA State settings.
  • At the time of writing SDRPlay released its RSP1B, which is not yet supported by QIRX, but with very similar specs as RSP1A. RSP1B comes in a black painted steel case instead of a plastic case (RSP1A

3. RSDdx

  • RDSdx is another great device from SDRPlay. As seen above if performs well on DAB. After doing a few tests on FM it seems to me RSDdx is almost on par with AirspyR2. The spectrum width of this device is 10 MHz, the same as AirspyR2. You can purchase an RSPdx for about 240 euros.
  • Performance on DAB is excellent as can be seen in the test results.
  • The RSPdx has three antenna connections. If you have a LNA connected to your DAB antenna only Antenna B will work as it supports Bias-T.
  • Antenna choice and Blocked Band are not retained for the next session, but this might be adjusted in a future QIRX update.
    The spectrum width can be set up to a nice about 8 MHz (Select 8192000 Sampling Rate in the QIRX Settings, Sampling Rate). Unfortunately my old laptop tends to crash with these settings.
    There is no ‘DX’ advantage in setting a higher sampling rate though.
  • As with the other devices the gain can be set to either auto (AGC) or manual (slider).
    This setting as also the Bias-T is retained.
  • Adjusting the LNA state is important and it can improve reception a lot.
Select Sampling Rate
  • In the QIRX TII tab Threshold and Average can also be set.
    In general it’s best to set the Threshold to Automatic.
    Manually setting the threshold level below the noise floor will produce weird and impossible TII values.
    Check the TII widget to visualise this.
  • The TII Average can be set to high for higher sensitivity and low for good realtime response.
    As with RSP1A it’s advised to carefully check all the settings especially when there’s DX in the air.
Threshold and Average

Conclusion

All three devices perform well on DAB. If your only interest is DAB RTL-SDRV4 or RTL-SDRV3 is an excellent choice. If you also want good reception on other bands and don’t mind adjusting a few settings every now and then you should go for an RSP1A or an RSPdx.

Many thanks to Clem Schmidt whose contribution and expertise were invaluable in the creation of this article.