April 9 2021 – Comparing Qt-DAB and QIRX

DAB DXing has become a quite popular niche in the European DX scene. Distances up to 800 km can exceptionally be covered.
Of coures a good antenna is advised. I’m quite happy with my stacked Emme Esse aerials.
Good DAB radios are not too expensive, but I prefer using SDR hardware like RSP1A, AirspyR2, RTL-SDR and nesdrSMArtee as these fine pieces of kit are affordable and offer some great possibilities when using software like QT-DAB and QIRX. Qt-DAB is being developed by Jan Van Katwijk (NL) and QIRX by Clem Schmidt (D).

What’s the best set-up with this hardware and software? Opinions differ as some set-ups are amazing for certain users and a disappointment for others.

Time for a quick test and review. All ‘eyes and ears’, no fancy equipment which I don’t master anyway.
SNR (db) readings are compared in different configurations.

1. RSP1A with QT and QIRX.
This is clearly a great set-ups and differences between QT and QIRX are mininal.
If you want to do some serious DAB DXing this is a good choice.

RSP1A
QT 3.71QIRX 3.1.2
5D21,528
6D2624
7A1116,2
8D2020
9B7,57,5
11A2027
11C1512,2
12A26,524,5
12C1713,5
RSP1A with QT and QIRX

2. RTL-SDR (R820T) with QT and QIRX.
The RTL-SDR (R820T) dongle is a very compact and cheap alternative for an Airspy or an RSP1A.
RTL-SDR and QIRX perform extremely well.
However QT struggles with R820T and some strong muxes just won’t decode data at all. It also produces lots of audio dropouts, which can be countered by carefully fiddling with the settings.

QT settings with R820T.


RTL-SDR and nesdrSMArtee are on par.
After running a while RTL-SDR becomes pretty warm, while nesdrSMArtee becomes hot, even warm when hooked up to a pc that is turned off (drawing current from the USB port).

RTL-SDR (R820T)
QT 3.71QIRX 3.1.2
5D1228
6D1821
7A17
8D21
9B98,5
11A2025
11C12,1
12A1725
12C13,4
nesdr (R820T)
QT 3.71QIRX 3.1.2
5D12,528,5
6D19,521,5
7A16,7
8D21,5
9B98,4
11A2025
11C12,7
12A1722,5
12C13,5
RTL-SDR (R820T) with QT and QIRX.

RTL-SDR and nesdr(R820T) with QIRX.

3. Airspy R2 with QT and QIRX.
The numbers look great and both QT and QIRX seem to do well. QT and AirspyR2 are in my set-up a match made in heaven. Decoding is swift and accurate.
QIRX and AirspyR2 don’t like each other. 5C DR Deutschland from Aachen, next to powerhouse 5D DB+VLAANDEREN2 from Veltem, is impossible to decode.
11C DAB+ from Eys and 11D BXL-BW1 from Wavre are tricky.
Sometimes QIRX will only run after a few tries and after closing it down a background process keeps running.

AirspyR2
QT 3.71QIRX 3.1.2
5D18,526
6D26,524
7A1721,5
8D2022,5
9B1512,5
11A2024
11C1812,5
12A24,524,5
12C2016
AirspyR2 with QT and QIRX.

What’s the final verdict? Which is the best set-up in my view?
6. QIRX+Airspy
5. QT+R820T (5C – audio dropouts!)
4. QIRX+RSP1A
3. QT+RSP1A
1. QT+AirspyR2 and QIRX+R820T.