DAB TII codes now in DABLIST

DAB - Digital Radio
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daveB
Posts: 1018
Joined: 07 Oct 2014 16:49

DAB TII codes now in DABLIST

Post by daveB » 21 Jan 2018 20:53

Our compatriots in Europe are getting very excited about being able to get TII codes from QIRX and qt-dab. Gunter Lorentz has added TII codes to the information in DABLIST (fmlist.org).

The data is in decimal format - the first two digits are the Main id - the last two are the sub-id. There do not appear to be nationally published lists, other than for the UK, so the enthusiasts are busy posting info on their local TII codes and DABLIST is being updated.

The latest versions of qt-dab and QIRX display both the TII codes and the Geographical coordinates (where available) and display the TII codes in decimal.

There are some key differences between qt-dab and QIRX regarding TII decoding. Qt-dab displays the strongest transmitter only whilst QIRX displays all the transmitters present on the frequency.

Qt-dab can use an rtl dongle (dabstick), sdrplay and airspy one. QIRX uses the dab stick via tcp-ip, but will also run with airspy as you can get a tcp/ip driver on the DabPlayer web site.

SDRplay on qt-dab is much more sensitive than the rtl-dongle for, I think, two reasons a) better dynamic range as it is 12 bit ADC b) better s/n ratio compared to 8 bit. Airspy is no better than than the dongle as the bandwidth is too wide - and is only 8 bit via tcp/ip..

For best decoding of weak MUXes both pieces of software require manual adjustment of the gain to get the best snr. Qt-dab running sdrplay at high gain will decode the three weak London MUXes (11B, 12A, 12C) most days with squitty audio. On QIRX or qt-dab running the dongle you can't even see the signal in the spectrum for 11B or 12A because they are sandwiched between two powerful MUXes. 12C is resolvable but nothing is decoded. But playback a signal recorded from qt-dab and it is almost as good as through qt-dab itself.

When evaluating the software - do remember that both Jan (qt-dab) and Clem (qirx) are doing it as a hobby - and are gracious enough to share the fruits of their labour. They both welcome constructive feedback to help them improve/de-bug the program, but don't expect to feed them a list of 'wants' and expect it to happen.

The same is true of the more commercial programs - and I now think it was sheer 'luck' that when I asked SDR# if it was possible to get an MPX audio output at 192 kHz they took in on board and Vasily produced it a couple of days later. Where would my FM DXing be without that option?
SDRPlay, AirSpyMini, RTL dongles, SB920s, Yamaha TX930. 5 ele compact yagi on rotator at 18ft agl. FM5 facing east, FM5 facing south, FM3 facing NE, OIRT dipole, 3-ele Moxon vertical facing east.

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