Comment on digital radio in Bris/GC:
https://radioinfo.com.au/news/canberra-darwin-dab-trials-complete-applications-open-licences
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Brad Smart has written an opinion piece about the potential signal strength of Brisbane DAB+ on Radioinfo: https://www.radioinfo.com.au/news/brisbaneās-dab-dilemma-gold-and-sunshine-coastsā-unwelcome-visitor
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What a load of crap!! Car radios can pick up reception of Brisbane on parts of the Gold and very southern parts of the Sunshine coast. Big deal.
For a start car radios are more sensitive and have better antennas then any portable receiver. So the average person at homeās unlikely to experience this. Secondly, hasnāt this been the same for Brisbane FM stations for ever? Let alone the AM ones!!
Itās the same for Melbourne and Geelong. You canāt get consistent DAB+ reception even on car radios in Geelong. Yet the Melbourne FM stations boom in. And for some inexplicable reason the Geelong commercial broadcaster apparently cries foul about the digital services only!
The FM stations have always been and will always be the issue. Not the few people who might at times be able to pick up fortuitous reception of DAB+ from out of Brisbaneās service area. Canāt imagine too many with the patience to drive around the Gold Coast trying to listen to something that keeps dropping in and out all the time.
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This suggestion also makes no sense as well.
Surely, a recalculation can be made on the proper height for the DAB antennas on the Mt Cootha tower to ensure roll-off of their coverage, relatively sharply, at Beenleigh.
Then, the Brisbane stations could utilise their full 50Kw of power within that service area to ensure thereās adequate field strength in those metropolitan areas, that are currently experiencing āblackspotsā.
(Very roughly) The Brisbane DAB+ antenna is on the Ten tower at 192m above the ground level that itself is approx 280m asl. That gives an approx radio horizon of 90km (Burleigh). If the transmitter was moved to near the bottom the tower, the horizon would still reach to Southport at 70km. To get a horizon to just Beenleigh (40km) the transmitter could not be higher than 100m above sea level - or some 10 story building at lea level. That would cut line-of sight to the majority of the licence area.
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Yes. Mr Smart aināt smart at all when it comes to technical matters!
Itās also the first time Iāve heard the Brisbane reception area described as flat!
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Itās far from flat, hence the reception problems within the licence area.
Sure, Brisbane doesnāt have plunging valleys or escarpments of great heights with population in great numbers at both the top and bottom, but it does have enough hills that do attenuate the DAB+ signal.
Take a drive east, the ring of suburbs that can āseeā the CBD are safe, good signal, usually good LoS to the TVQ site.
Drive east of Carina, beyond Bob Jane outbound and you go through a small cutting to Carindale at Creek Road. Signal starts to drop here due to that line of hills which is a spur of Mt Gravatt running north to south from Cannon Hill to Mt Gravatt East before heading west to Mt Gravatt.
Signal is further impacted by the next line of hills at Chandler beyond the velodrome/pool etc.
This puts you into Capalaba and still well within the LAP. Next suburb east, Alexandra Hills sees signal further impacted so that by the time youāve climbed the hill into Ormiston and descend to Cleveland, more problems with signal in the Cleveland main street.
Federal MP and local drinking showpony, Andrew Laming knows signal is bad, he canāt receive it in his second floor Cleveland office.
This problem is replicated all over the LAP and seeing where new development is going in and in big numbers in outer suburbs, thereās a lot of areas inadequately serviced by DAB+ who wonāt bother and go to other non radio options.
Ipswich is another trouble area as the signal is limited to assist a DTV service no longer on 9A from Mt Dowe post restack.
Bradās article failed to mention the ABCās desire for full power at 50 kW ERP separate to commercial restrictions.
I found this amusing,
While superficially, SCA may be happy to see wider coverage for its Brisbane services through the Mt Cootha multiplex, the company also has two Gold Coast stations, whose revenue base needs protecting.
And what Brisbane commercial stations now have the least coverage towards the Gold Coast? Surprise, 104.5 and 105.3.
Thereās also the option of OD patterns for the adjacent metro markets, quid pro quo for them. But would it be commercially beneficial or a nice to have?
Would like to hear thoughts from @radioengineer who did a lot of work on the Sunshine Coast in anticipation of DAB+ as seen in their submission.
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A dumb technical question for the techies. I thought analogue transmissions were specified as either OD (omni directional - ie same power in all directions) or DA (directional antenna - ie different power in different directions). Is this not possible with digital transmissions?
If Canberra, the ABC SBS multiplex is now broadcasting on channel 9C.
The ABC services on the test multiplex are now really distorted.
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TACO in Sydney is STILL just dead airā¦
This baffles meā¦as it has been mostly like this since Julyā¦ WHY was it even there in the first placeā¦?
The Almost Continuously Off channel?
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Well said, and if anything my experience with the Brisbane DAB+ signals is that they (roughly) match the strengths of their FM counterparts from the same location
Itās a myth to suggest Brisbane FM mysteriously drops off at Beenleigh - itās of local strength well beyond the Albert River and down past Pimpama into Helensvale, where it starts to tail off a bit. Itās amazing more of an issue hasnāt been made of this before, especially given when travelling the other way the Gold Coast signals do drop off anywhere north of Beenleigh
Also, itās unsurprising Southport CBD receives good Brisbane DAB+ signals - itās on a big bloody hill where the FM (and even TV) services also boom in
The above is not to say a 50kW broadcast power wouldnāt result in additional spillover, but at the moment itās not doing anything on digital the analogue services arenāt
And yeah, those Bayside coverage blackspots are real. In fact, anywhere ESE of Mt Gravatt suffers. I donāt know if 50kW can be more highly directional to address these issues without greatly increasing overspill to neighbouring markets, but that would seem a sensible option going forward
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On my Sangean the āpruneā function doesnāt work, donāt know why, so Iāve annoyingly got some ABC and SBS stations twice though a couple have slightly different names.
I know DAB repeaters in Sydney exist on the Northern Beaches, in the CBD, and at Campbelltown, the obvious solution to me would be to install 1 or 2 around Redland Bay or Capalabaā¦ Iām guessing it canāt be as simple as that otherwise it would have been done by now??
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Commercial Radio Australia CEO Joan Warner has responded about Brad Smartās opinion piece on Radioinfo about Brisbane DAB+ coverage: https://www.radioinfo.com.au/news/brisbane-dab-claims-are-flawed-joan-warner
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I once email the commercial radio team on some stations using FEC 4-A.
FEC 4-A requires around 4 times the TX power to match FEC 3A to give the same signal strength. The international level of protection standard for DAB Terrestrial broadcast appears to be level 3. Given patchy coverage in some parts of Sydney, people could blame the DAB radio as a product (when listening to say 1sm which broadcasts at 4A). Not sure if this is a similar situation in Brisbane.
I suggested commercial radio should standardise the error checking to 3A (similar to ABC/SBS radio) . DR Plus basically said each radio broadcaster can choose whatever error level they wish to choose. They donāt mind if there is inconsistent reception. It seems to mess up my DAB radio in the Mazda but that is a different story :).
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Heres a question. Can a broadcaster choose to broadcast at a lower power if they choose to? Say to save electricity. Analog only. Just curious as they can indirectly do this on dab.
On analogue, yes - they can broadcast at any power up to their licensed power.
On digital they canāt - the entire multiplex has to be the same power (although this can be less than the licenced power).
Using stronger error checking requires more bandwidth, which results in less space for stations, but has the ability is being able to be received with weaker reception. Using a weaker error checking is the opposite, and neither options change the cost of electricity.
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Rebel Media proprietor, Aaron Jowitt, has his say about the overspill of Brisbaneās DAB+ coverage: https://www.radioinfo.com.au/news/play-ball-brisbane-digital-radio-rebel-fms-aaron-jowitt
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I think amalgamation of adjacent licence areas is a good idea. But Rebel and Breeze are adjacent to and overlap numerous Qld and NSW licence areas. Do they want to merge with all those licence areas?
If ACMA were seriously proposing to co-channel Rebel with Radio 97 they either have rocks in their head, or way too little spectrum to play with
Iām still yet to be convinced that using Band III for DTV was a good idea given DAB+ was on the horizon. UHF should have solely provided DTV (with maybe one other group of channels kept for TV and not sold off), leaving Chs 6-12 free for a nationwide rollout of DAB+. Instead we have this debacle
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