Jump to content

DAB Radio in the UK


QBox User

Recommended Posts

Using the DABradio "prototype" application with a Realtek 2832U device, I have not been able to detect any stations. My local mutiplexes are in the range 218 - 226 MHz and should be strong enough for indoor reception. I have tried two aerials (VHF "string" and UHF log periodic). These work OK with other SDR applications (ADSB# at 1090MHz, SDR# at VHF/FM).

 

Before I set up an external aerial, can someone confirm the application is compatible for UK DAB reception?

Link to comment

DAB is DAB and if your device is listed in the application you should be able to scan and find those channels. Don't expect too much from the application i made, i do not know any directshow audio decoder for dab+.

 

Christian

Link to comment

I can see no device listing in the application - did I miss some hidden menu? The Scan button is enabled, though, and lets me select the "Europe" option, after which the bar runs from left to right in a couple of minutes, with no indication of tuning success.

 

There's no DAB+ in UK. MPEG is presumably OK.

 

I'll give it one more go outside, using a laptop.

Link to comment

Usually the tool should just show you an error message if no Realtek device is found. If it is scanning, it should be able to receive dab channels in general. The reception is quite weak in general and DAB is made completely in software, so don't expect to much out of it.

Link to comment

There's no error message - the progress bar moves to the end, the status at bottom left is "Paused...". I guess it sees the device, but no signal.

 

I tried a few alternative DAB applications. Most seem tied to specific manufacturers devices. The only BDA-compliant application I found is Blaze HDTV version 6.0 which came with the stick. This works with the DAB tuner but the latest v6.6 from the Blaze web-site didn't seem to find the DAB filter (though it did work with the FM source). DAB has been removed from the "readme.txt" file in 6.6 so support may have been dropped.

 

The Blaze scan found all 3 local DAB multiplexes - one at 100% strength and quality, the others somewhat weaker. The strong mux played well even with no aerial connected, the second had some interference while the third had no decoded audio at all. I'll try it on an external (TV) aerial tomorrow.

Link to comment

Well, the roof aerial improved reception for all muxes. Blaze gave good reception on 2 but could not decode the third (UK National D1). It will only decode some of the stations in the other muxes.

 

I finally got DabRadio.exe to scan in the muxes. The last thing I did before this worked was to drop "RealTekDAB.dll" (from Blaze) into the application folder and then rename RTKDAB.dll. I repeated the exercise later to see if was just a coincidence.

 

The application plays back all stations, though audio quality is poor. The recordings play back perfectly in VLC, so I'm assuming it's just ffdshow. No matter which decoder (of 5) I select for MPEG Layer II (assuming that's the correct one), the ffdshow icon always appears in the tray when I start playing. How can I change this? ffdshow is first in the list.

Link to comment

Hmm, the rtkdab library i use was the latest build at the time i published the application. The decoder is used after a restart, so you should start the application, select the decoder for mpeg2 audio and close the application. It should use the decoder you selected.

Link to comment

Decoder change only seems to be remembered reliably when I click on another format before closing, but manual selection has no effect. The program seems to remain on "Auto", with ffdshow being first in the list. The only way I could stop it being selected was to disable it from being used by the DabRadio.exe program.

 

Something else is now being selected. AC3Filter is next in the list, but there's no indication if it's used (no tray icon, even when selected manually). Whatever it is, it's better than ffdshow, but there's still some "popping" and it sounds the same no matter what I select as "preferred".

 

Blaze and VLC sound much better, but they use their own audio decoders.

 

I failed to get any reception on the XP laptop. Blaze didn't even see the DAB or FM tuners, so I suspect the Realtek XP drivers are not as functional.

 

On the DAB operation side, many stations stop playing, even those on the same mux as working stations. Does the arrangement change dynamically? Rescanning seems to restore operation. Blaze is the same.

 

One other point - the scan process sometimes picks up a duplicate mux. On the last scan, 225.65MHz was repeated at 234.21MHz. With Blaze, I've seen 223.94 repeated at the next block (11N - 224.096). Maybe the bandwidth setting is too wide.

Link to comment

Well, of course the application is using RTKDAB.dll. I'd forgotten about dropping a copy into Windows\System32 :blushing: This is what must be done with the downloaded DLLs so they are in the PATH. The original problem can now be described as SOLVED, though the audio is still not right.

 

I played back recordings in DVBViewer Pro, selecting alternative decoders, including the ffdshow/libmad one DabRadio plays by default. The audio was fine, with none of the distortion heard in DabRadio, so I can't blame the decoders. Something else is going wrong.

 

DirectSound Device Properties window shows discontinuities at a rate of about 10 per second on live ffdshow decoding but nothing on recording playback. Maybe buffering not adequate?

 

I installed the device on a Windows 7 platform and got exactly the same results as with Vista.

Edited by QBox User
Link to comment
  • 4 months later...

 

I finally got DabRadio.exe to scan in the muxes. The last thing I did before this worked was to drop "RealTekDAB.dll" (from Blaze) into the application folder and then rename RTKDAB.dll. I repeated the exercise later to see if was just a coincidence.

 

 

Thanks for the hint. I did a "similar" solution, but I took the original (from Blaze) RKTDAB.dll and copied it to the DABRadio folder, after renaming the dll that came with DABRadio.

I'm located in Sweden and now the DABRadio finds both muxes, one DAB (225.65 MHz) and one DAB+ (227.36 MHz)

Link to comment
  • 1 month later...

One small issue. Station #2 is actually SR Världen. So I guess that the special character 'ä' is not read correctly? Maybe it can be fixed?

Station #13 is Skärgårdsradion, hence a second special character 'å' is used.

 

Final issue. Would it be possible to add a volume control to DAB radio? Right now the listening volume is much higher than when listening to DVBViewer.

Thanks for a great DABradio!

Link to comment

Hmm to be honest it is quite complimentary that somebody use this application :) I used the tool for testing purposes and the current state is quite a mess in between the released version and what it was intended to become. The idea was to assemble a dab(+)->dvb converter which "emulates" a dvb device. I unluckily do not have the time at the moment to continue the work on this subproject and especially since there are no proper (directshow) decoders capable to play the dab+ stream i get from the realtek api it does not make sense to continue working on it.

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...