Digital Radio is nothing new, after all, the Digital Radio Plus campaign has been running for a while, advocating radio that doesn’t sound like sh*t. Yeah right!
I suppose if you’re in the market for a Digital Radio, you would have looked around for some cheap receivers. And you may have seen these clunky behemoths going for anywhere from about AU$30 to AU$50.
The radio on the left was purchased on special from Kogan, the right radio purchased from another online eBay retailer. The funny thing? Both radios are pretty much the same – but the Kogan one is better since the Shintaro one here has a firmware bug that causes a reboot loop when entering DAB mode on startup – an RMA did not help. The Shintaro also suffers from digital hash noise in the audio which is much better tamed on the Kogan unit.
Both radios require 4xAA batteries for power. Both feature a mono internal speaker. Both feature a telescopic antenna, a headphone output, and a 6v external plug pack input. Both come with a plug pack. Both even have a 16×2 character LCD display.
The Shintaro has a hardware power button, the Kogan has a software power button. The Shintaro has a much more sensible transflective LCD which can be read without a backlight (additional power draw), whereas the Kogan one does not. The inbuilt speaker sounds boomy and mediocre, but the Shintaro one has more digital background hash noise. The Kogan model has an addition – a miniUSB B port in the battery compartment to update the firmware – not that there is any firmware available.
Why have I listed the features as such? If you come across a radio with a 16×2 character LCD, you can almost bet that it’s built upon the Frontier Silicon FS2052 Verona chipset. It’s not a bad chipset – it’s got decent power efficiency, a FM mode with RDS and average sensitivity, and a DAB mode with good sensitivity overall. And it’s obviously not too expensive.
It also lets you see a rudimentary signal meter, an error level indication in arbitrary units, the multiplex name, frequency, bitrate, codec. It’s better than knowing nothing about what you’re listening to!
The Kogan unit has dab-mmi-FS2052-0000-0300_V4.1.17.EX17682-1A1 firmware, whereas my Shintaro unit has dab-mmi-FS2052-0000-0090_V18.104.22.168059-1A4 firmware. Strange how the version of the firmware on the Shintaro seems newer but is more problematic.
Of course, not all radios are FS2052 based. I picked up another eBay special – a Fulljoin radio which is much more compact, with internal Li-Ion battery and multi-line display for about AU$60. It even has a microSD slot, and can play MP3’s and record to microSD. It has about 128Mb onboard flash memory. It also has an FM mode with RDS as well. It has a manual cut-over of speakers to earphones as it relies on the earphone cord as an antenna. Charging is through a microUSB B port underneath the radio. It’s cute – I wish I could love it though …
I can’t recommend this radio since it has shockingly poor sensitivity. It’s quite unusable indoors where the FS2052 based units have no trouble. Even with enough signal, this unit stutters periodically as if there’s a sample rate matching issue and this happens to all the recordings too which are made in .aac format but in a non-standard stream format that only VLC seems to be able to understand at the moment. So while it has great features, the execution is so poor as to make it not worthy of recommendation.
The unit does have access to a diagnostic RSSI (likely as dBm but as a positive number) and BER indicator. The firmware is listed as SM342-DABDemo with APP: I0426-0 and SDK: 0.11.08. Unfortunately, this means that it’s likely that this is a diagnostic or demo build which hasn’t been properly ironed out or customized. This tells us the chipset – a Silicon Motion SM342 Cello, but it doesn’t tell us much about the front end which is used, which is rubbish.
There’s also the expensive Pure branded receivers with their unusual battery requirements and high prices … but most of the digital radios are rather chunky and require a fair amount of battery power. That’s one mark against convenience. And I haven’t seen tuners integrated into many devices either.
Sydney DAB+ Multiplexes
I did a thorough survey of the channels with my FS2052 based radios – the list below covers the services available in Sydney as at 07/06/2013 at 20:35 (UTC+10):
Multiplex Name: DAB+ Sydney 1 Channel: 9A 202.928Mhz Services: 18 2DAY 96kbit/s 2OOO Languages 64kbit/s 2RPH Digital 64kbit/s 2SM Talk & Sport 32kbit/s 2UE-954 80kbit/s The Buckle 48kbit/s Buddha Radio 64kbit/s Fine Music 64kbit/s GorillaDanceHits 48kbit/s Koori Radio 64kbit/s LoveLand 56kbit/s RADAR-New Music 56kbit/s SkySportsRadio1 64kbit/s SkySportsRadio2 32kbit/s Sky Racing World 32kbit/s Stardust Radio 48kbit/s Triple M 96kbit/s ZOO MusicVariety 48kbit/s --------------------------- TOTAL MUX RATE 1056kbit/s Multiplex Name: DAB+ Sydney 2 Channel: 9B 204.640Mhz Services: 20 2CH EASY 1170 96kbit/s 2GB 873 96kbit/s 2MFM Muslim DR 64kbit/s 2SER 107.3 48kbit/s Apna Digital 32kbit/s CW Remix 32kbit/s Edge Digital 40kbit/s FBi Radio 64kbit/s Inspire Digital 64kbit/s Koffee 64kbit/s Mix 106.5 48kbit/s Mix '80s 32kbit/s Mix '90s 32kbit/s Nova 969 64kbit/s NovaNation 64kbit/s smooth fm 95.3 64kbit/s South 48kbit/s Star Observer 64kbit/s WSFM 4 Kids 32kbit/s WSFM ClassicHits 48kbit/s --------------------------- TOTAL MUX RATE 1096kbit/s Multiplex Name: SY abc&SBS RADIO Channel: 9C 206.352Mhz Services: 19 702 ABC Sydney 64kbit/s ABC Classic FM 80kbit/s ABC Dig Music 80kbit/s ABC Jazz 80kbit/s ABC Country 80kbit/s ABC Extra 72kbit/s ABC Grandstand 40kbit/s ABCNewsRadio 48kbit/s ABCRadioNational 64kbit/s SBS PopAraby 48kbit/s SBS PopDesi 48kbit/s SBS Radio 1 40kbit/s SBS Radio 2 40kbit/s SBS Radio 3 40kbit/s SBS Chill 56kbit/s SBS Extra 48kbit/s SBS PopAsia 64kbit/s triple j 80kbit/s triplejUnearthed 72kbit/s --------------------------- TOTAL MUX RATE 1144kbit/s
It is interesting to see that most of the multiplexes are packed to near capacity. According to Wikipedia, the settings used by the UK yield a data rate of 1184kbit/s per multiplex, so our multiplexes are 89%, 93% and 97% full respectively. If we’re only allowed to have three multiplexes in Sydney, the surplus capacity is likely to be 128kbit/s, 88kbit/s and 40kbit/s respectively which is enough for a few more channels.
One of the things to note is that all of the channel names have been entered in verbatim as it is displayed on my digital radio receiver. There are some interesting things done to squeeze things into a given space. Another thing to note is that Australia is running all DAB+ services, so all services are encoded with AACplusv2 which uses technologies such as SBR to enhance the frequency response without adding much to bitrate.
Unfortunately, a close listen finds that while the background noise in good digital reception is pretty much zero (as it should be) increasing the signal to noise ratio – and brief limited signal interference typically has little effect, the audio quality of the transmissions is lacking compared to a good FM receiver. The reason for this is a muddy treble and moderately poor stereo imaging which results from the lack of bitrate allocated to their channels. Of course, the spectrum is limited, and the multiplexes set by the government – so in order to increase variety so as to try and increase listenership and possibly ad revenue, the quality of the services goes down!
Haven’t we seen this somewhere else before? Oh yes we have – when digital satellite TV came in, and when the Freeview campaign for more variety came in. Variety is at the cost of quality when your bitrate and coding schemes are restricted.
I suppose I cannot whinge too much since some broadcasters offer even worse bitrates online – this is probably due to logistical issues with bandwidth for listeners and the large number of people using mobile broadband connections with very expensive limited quota to do streaming – those are the sort of people who appreciate the low bandwidth I suppose.
Interestingly, DAB+ could make this kind of streaming redundant if it was integrated into more devices – phones, tablets, etc and if some diversity was introduced. Unfortunately, transmit diversity and time interleaving is still a concept which has not been adopted – but ultimately, if you send the same digital stream on two frequencies offset by time, it is highly likely that a person equipped with two separate receivers each tuned to one of the frequencies recombining the digital data will not see errors in both streams simultaneously. It’s better than basic receive diversity where two antennas are separated in space, and decoded separately and recombined as strong local phenomena can overwhelm both receivers. Satellite radio services in the US (XM Radio) broadcasts in this fashion so that cars driving through tunnels rarely experience any interruption in listening – that’s one thing I really like about streaming over the internet – it’s the fact there’s a buffer. Someone do this for DAB+ please!
A breakdown based on broadcasters is below (to my knowledge, this *should* be correct):
Mulitplex Name: DAB+ Sydney 1 Southern Cross Austereo: 416kbit/s (39%) Sky Racing: 128kbit/s (12%) Fairfax Radio Network: 128kbit/s (12%) Broadcast Operations Grp:128kbit/s (12%) Community/others: 256kbit/s (24%) 2OOO: 64kbit/s 2RPH: 64kbit/s 2MBS: 64kbit/s 2NLD: 64kbit/s ---------------------------------- TOTAL 1056kbit/s Mulitplex Name: DAB+ Sydney 2 Macquarie Media Network: 192kbit/s (18%) Australian Radio Network: 264kbit/s (24%) dmgRadio Australia: 256kbit/s (23%) Community (below): 384kbit/s (35%) 2MFM: 64kbit/s 2SER: 48kbit/s Radio Apna Digital Sydney: 32kbit/s Star Observer: 64kbit/s FBi Radio: 64kbit/s Hope Media: 64kbit/s South: 48kbit/s ----------------------------------------- TOTAL 1096kbit/s Multiplex Name: SY abc&SBS RADIO ABC: 760kbit/s (66%) SBS: 384kbit/s (34%) -------------------------------- TOTAL 1144kbit/s
Interesting is to see how many bits some of our broadcast networks hold. ABC has a lions share, followed by Southern Cross Austereo, SBS, Australian Radio Network, dmgRadio Australia, Macquarie Media Network. Then it’s followed by Sky Racing, Fairfax Radio Network and Broadcast Operations Group all with 128kbit/s each. The others and community channels do add together to a respectable 896kbit/s.
I suppose if you’re deciding whether to buy a digital radio or not, this could help … but overall, I’d say that there really aren’t many compelling reasons to do so given the fact that these stations are mostly available streamed through the internet as well, and that digital quality isn’t “superior” as such. It’s not like digital TV where analog transmitters will be switched off – analog radio has no plan of phasing out in the near future.