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Old 01-08-2018, 22:56   #1
AlexDRM
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[MW] All India Radio AIR via Delhi 828 kHz, 1368 kHz

I receive All India Radio on 828 kHz and 1368 kHz with very good signal on a KiwiSDR in Delhi, but I cannot decode any audio. DREAM does not show any audio bitrate, only "AIR Journaline".

Here are some screenshots:
AIR-00828kHz PNG
AIR-01368kHz PNG

And an IQ-recording of 828 kHz:
AIR-00828kHz WAV

Does AIR employ xHE-AAC on MW? Is this the reason why DREAM does not decode anything?

Last edited by AlexDRM : 17-08-2018 at 01:28.
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Old 02-08-2018, 17:15   #2
Radioeng
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AIR 1368 kHz in pure DRM

I had the same result using the same KiwiSDR and Dream. I am curious to know why this is happening. The SNR is very high but the MSC CRC status is always blank even though the constellation looks extremely good.
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Old 03-08-2018, 09:09   #3
Cumbredx
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xHE-AAC

Yes, they run xHE-AAC on some of their MW transmissions.
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Old 04-08-2018, 01:11   #4
Owdjim
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I've had the same non-results with that KiwiSDR. There's also one AIR DRM outlet that can be received on 810 kHz via the Qatar KiwiSDR, but I haven't been able to decode anything from that either. Decoding (or not!) locally received xHE-AAC gives me a "no codec" message in Dream. I don't get this with the AIR ones via KiwiSDR. I can decode other SW DRM tranmissions via KiwiSDRs.

73 Chris
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http://www.owdjim.gen.nz/chris/radio/DRM/ http://kiwisdr.owdjim.gen.nz:8073

Last edited by Owdjim : 04-08-2018 at 01:17. Reason: Fix location error
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Old 04-08-2018, 04:09   #5
AF4MP
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in addition to Chris' comments the screenID indicates that they are transmitting MM (multi-mode) and the Journaline Tab is highlighted.

Clicking on the Tab shows a blank Journaline. (The choice of audio codec does not have any bearing on the working of this particular multi-mode feature).
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Old 04-08-2018, 13:32   #6
Owdjim
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Looking at the spectrum of the TWR Dehli KiwiSDR makes me think it may not be very good on mediumwave. Signals look very noisey. But I also do worry AIR may be using some settings that Dream cannot handle. If that is the case, where are all us enthusiasts left? I might have to ask for my DRM Supporter fee back ;-)
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http://www.owdjim.gen.nz/chris/radio/DRM/ http://kiwisdr.owdjim.gen.nz:8073
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Old 17-09-2018, 12:29   #7
Owdjim
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AIR 1368 kHz is decoding today (2018/09/17) via the TWR New Dehli KiwiSDR. 2 x 8 kbps AAC streams: AIR Rainbow & Vividh Bharti. Both suffer dropouts.

Cheers, Chris
Attached Images
File Type: png AIR1368.png (12.4 KB, 47 views)
File Type: png AIR1368a.png (12.5 KB, 42 views)
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http://www.owdjim.gen.nz/chris/radio/DRM/ http://kiwisdr.owdjim.gen.nz:8073

Last edited by Owdjim : 17-09-2018 at 12:34. Reason: Add screen shots
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Old 20-09-2018, 10:47   #8
zfyoung
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Both services are at the same bit-rate. As far as I can see the only difference is UEP and EEP (Unequal Error Protection / Equal Error Protection). Theoretically, UEP should be more robust(ie. less drop-out) than EEP, yet the listening test prove the other way round. I doubt if the FAAD AAC decoder used in Dream has implemented UEP properly or at all!

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Last edited by zfyoung : 21-09-2018 at 01:37.
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Old 21-09-2018, 06:31   #9
Radioeng
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I think they are back using xHE-AAC. Very poor reception using KiwiSDR in Delhi. Dream opens Journaline no matter which service you choose.

Kevin (radioeng)
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Old 21-09-2018, 08:29   #10
Radioeng
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Listening to AIR Delhi on 1368 kHz at 07.30 UTC via KiwiSDR in Delhi and the txer is running two channels in aac, both 8.08 kbps. The programmes are Rainbow and Vividh Bharati. The signal is poor and not decoding much audio.

Kevin (radioeng)
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