I can get Mandurah in the southern Perth suburbs by FM or DAB, but differently. Both require a good FM/DAB indoor radio or car radio. The FM reception is consistent but tends to be subject to noise fading and I suspect the stereo switches to mono most of the time. DAB is a different story. In the car it will come and go as you drive around (there 1 minute gone completely the next), so completely unusable. For indoors if you can find a good spot it is great, just don’t move the radio (or move around the radio), and you get crystal clear stereo sound which is the best around (given the bit rate of 96 kbps). So in the car best to use FM, at home best to use DAB if the station can be picked up.
I guess in the Mandurah target area it is the quality from the high bit rate (DAB better than FM) and maybe that will help pull more listeners away from the Perth stations. That is, if you have a DAB radio.
Which would result in Perth licensees breathing a sigh of relief.
We know almost all commercial licensees worry most about fragmentation within their blinkered view rather than of all media choices which are growing by the year.
Reading that of the southern Perth suburbs fortuitous reception difficulties of Mandurah DAB+, I would say the agreed engineering was too conservative and should’ve matched analogue overlap. Especially considering the FM overlap in many eastern state metro/adjacent metro markets.
Hello all. I’ve been playing around with my RTL stick and DAB stations today and yesterday. It has me wondering, do you think there is a way of recording the entire ETI? I am thinking similarly to how you can record the entire TS for DVBT and play it back later in TSReader.
Fortuitous is the word. Given DAB+ is on the TV frequencies it is subject to the same line of sight issues. If am driving along Mounts Bay road around Kings Park (pretty much in Perth CBD) I have uninterrupted reception (because it is unobstructed to the south-east across the river), but it starts to come and go the moment I travel south along the freeway (because it is builtup to the east). Also even from my upstairs view to the south-east where I get reception on my DAB+ radio the signal strength is always around 30 (out of 100), not sure what means but it is at the threshold, so less sensitive radios would not pick up anything. Of course at that low signal strength obstructions become a major factor (not enough strength to “go around or through”).
Makes me wonder how close you have to be to the license area to get unwavering, indoor reception on your bog standard DAB radio no matter where it is placed, I suspect you have to be within rather than just outside.
There’s an option inside the DABPlayer software to ‘Save Baseband Data’ that appears to do this, however I’m not aware of any software that actually opens it, but the file size would be consistent with that being what it’s recording.
Oh that’s fantastic! Thank You Moe. I’m looking to start archiving radio the same way I do with TV, so this is a great start.
EDIT: I have been recording Sydney DAB2 in baseband. Holy mackerel. 2.3GB for 10 minutes! To archive both of the streams would be over 660GB/day. But goodness me, imagine how incredible that would be?
As Sydney 2 DAB covers a quarter of RF Channel 9A (which is DAB 9A, 9B, 9C and 9D being unused), I would have thought Sydney 2 DAB should be more like 430 MB for 10 minutes (calc below)
An RF channel can handle 23 Mbits per second = 2.875 MB per sec.
Sydney 2 DAB is a quarter of this = 719 KB per sec
719 * 600 (10 mins) / 1000 ( convert to MB) = 431 MB
Or have I missed something here?
Perhaps recording it in baseband means that data is being “unzipped” on the fly and you have the full unzipped dataset?
That 23 Mbps figure is specific to DVB-T with 64-QAM 3/4 forward error correction and 1/16 guard interval. There is no fixed Mbps rate that a 7 MHz channel can handle – it depends on the broadcast standard. For example, DVB-T2 can do about 30 Mbps in the same 7 MHz. DVB-C2, which doesn’t need as much error correction and uses higher QAMs can do 80 Mbps+, with future extensions getting it up beyond 100 Mbps (DVB-C usually uses 8 MHz channels, however).
Assuming EEP-3A, if you were to record all of the channels on 9B, it should only be 1,152 kbps.
1,152 kbps = 144 kBps = 0.14 MBps = 8.4 MB a minute = 504 MB an hour = 11.8 GB a day for the entire decoded 9B mux.
I believe that baseband recording refers to recording the raw analogue RF data (as digitised by your SDR device), as opposed to the decoded DAB+ signal.
Hmm - I suppose baseband data’s not what you want then - though that would be the path to then decoding it back - as you could feed that data as a file source into an SDR based DAB receiver - looks like https://github.com/JvanKatwijk/qt-dab can do so.
I’d assume it would be possible to make software to decode and save off multiple audio streams at once - but seems like that doesn’t currently exist. Can’t see it being a technical limitation - it’s no different to being able to record multiple TV channels from the same multiplex at once - just that DVB software on PC is far more mature than the DAB equivalents.
On another matter, changes to SEN Melbourne, and 3MP for reference as there’s still an overlap in their usage:
1116 SEN - 40kbps 3A 30CU
SEN Sydney - 40kbps 3A 30CU
SEN2 - 32kbps 4A 16CU
SEN Track - 32kbps 3A 24CU
easy music 3MP - 64kbps 3A 48CU
Rythmos - 40kbps 4A 20CU
Niche Radio - 40kbps 4A 20CU
Spaced it that way due to the order in the multiplex allocation.
This ended up taking a lot longer than I expected - but just to visualise those SEN changes - as well as the Capacity Unit vs kbps difference, here’s the breakdown of 9A in Melbourne - and the unnoticed launch of Light Christmas…
I tried for Brisbane DAB at St Helena Lookout near Byron Bay this afternoon. As soon as I pressed the DAB icon on the car radio, the list of Brisbane DAB stations popped up but couldn’t get any station to decode/play.
Had a gift card from Hardly Normal to use up, so I picked up this puppy…
First impressions, sounds pretty good, but when it scans for DAB, it groups them by network operator, not in alphabetical order. I could be wrong, it could group them by the channel, like 9A, 9B, etc…
Takes the capacity units to 144, over their 1/9th allocation, but offset by Coast FMs 72 CUs - 96kbs @ EEP 3A protection.
I’ve previously been able to attenuate the Mandurah DAB signal down to 4 db and still decode the Wave using 2A, 1A should be quite impressive. Strong coastal ducting today here into Bunbury, so can’t attenuate the signal low enough to test.
