Digital Radio - Technical

Yeah the signal strength did increase from the days of the test tones, but since the introduction of the song track the signal level has been unchanged (at least as far as I’ve observed).

The change in bit rate of service 3 from 64 to 48 is new (and not as nice on the ears).

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I also picked it up in the car over the weekend on the upper North Shore (3 services) which was quite surprising, but no sound came through on any service from my location.

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Been doing a bit of driving between Brisbane & the Gold Coast, and I have to say how impressed I am by the seamless switching between the ABC DAB+ services.

I was on Mt Tamborine the other weekend and, apart from a few short patches where signal dropped out, coverage across the Eagle Heights area was totally unnoticeable. The same goes down on the Coast itself - the only way you’d know you’ve swapped transmitters is that it shows the ‘BR/GC ABC&SBS RADIO’ line up the top of the radio.

Similarly, it is good that ABC Brisbane is carried on GC DAB+. No need to retune at all driving down listening this morning.

A credit to all involved on this, both in getting DAB+ services operational on the Gold Coast, and for the excellent engineering in delivering them so well.

Now let’s hope for FM RDS-enabled services to do the same one day soon… :zipper_mouth_face:

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I was hoping my i30 was capable of this but alas it isn’t :frowning: what sort of car was this in?

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I tested out the trial East Sydney 8D DAB+ coverage in the car on the way back from Sydney this morning…

Could get some reception in the Shire, but was a bit patchy particularly around Taren Point where it is a bit lower… but still mostly OK… there were still a few dropouts around Brighton Le Sands too…

On the north side, it’s a similar story, a few drop outs around Turramurra too, pretty much gone completely once I got on the M1 at Wahroonga.

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2022 Subaru Forester with the stock radio - just automatically shifts between the two signals. Not sure if the other receivers will do it also, will have to check them.

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I’m getting UTC this morning on 9B in Melbourne (DAB Melbourne 2). 9A and 9C are OK.

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UPDATE: It’s back to local time now.

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My experience around NW Sydney is it is patchy at best on our work truck radios, however they have standard retractable car antennas from yesteryear, not designed for DAB+ I would assume the signal would be much better on a more modern car DAB+ tuner with a shark fin antenna designed for DAB+ reception.

There are spots in Blacktown with good LOS towards Sydney where I can get stable signal. Near the water tower at Acacia Gardens is a good spot, also along Sentry Drive near the Goal and into Stanhope Gardens it was patchy.

In the Hills district there was a spot along Quarry Rd at Dural where the LOS was so good you could see the city skyline here the signal maxed out, but as soon as direct LOS was lost it returned to patchy to no signal.
I also had some patchy signal in the car park at Fagan Park in Galston.

Here is a Nautel coverage map I have created, and it shows that coverage is possible mid Blue Mountains and Kurrajong Heights.

On the Central Coast potentially, Rumbalara Reserve, and near the BAI TV tower at Bouddi.
In the Illawarra reception is possible at Saddleback Mountain, and my hunch the Mittagong lookout at the GIB. Canberra DAB+ will still be received from the Bowral lookout. @Dani-Chan if you get a chance to get up there with your portable??

I have a couple of days off mid week so might do a dxing trip or two.

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@Ant5476 Try the extendable car radio antenna at a length of 73-75cm. That should provide roughly optimum DAB+ Ch 8D reception on such an antenna.

Nice helpful Nautel Map BTW - thank you.

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Thanks @ozbark yes I had made some adjustment similar to what you have suggested. The work truck DAB+ car radios are not very sensitive and perform poorly on fm too. in areas that have green 66duBV coverage for King Cross DAB+ signal is patchy so that may have a lot to do with it.

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I am late to the 8D party. I get sketchy reception up around Pennant Hills. In parts of Carlingford it is almost non-existent. I went for the Manly Ferry ride and at the start it was ok maybe just in the cliff and above at the start but then it wasn’t far into the journey it was very good. I’d argue 9A-9C is better because of centrepoint being very high but similar as you move into circular quay.

It is fun to have another DAB freq outside of the normal metro stations to try out. I wonder if suburban community station can be on the same frequency with the existing FM infrastructure for each community station linking together. That is probably unrealistic given what we are seeing at SWR as this needs money

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Do you mean like 2HHH Hornsby, 2CCR Parramatta all operating on a DAB TX each in their own markets all sharing eg 8C? If so, I think they would interfere with each other too much.

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Im wondering if maybe they can operate a SFN and have all suburban on one network of mpx. That way everyone can enjoy the programming from these stations across the city

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Agree, but they must be instructed to retain their local identities and focus so they don’t try to compete with the metro wide community stations and try to be an “all Sydney” station.

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If they were to do that and use 8D they would need to relocate it to Artarmon with similar specs and OCR’s as the existing Sydney DAB+ services. I agree all sub metros would have a condition on their licence requiring them to continue to serve their licence area.

With sub metros moving to DAB+ gives the option to clear their fm frequencies for future AM to FM conversions / AM band shutdown.

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I have no insider knowledge on this, but my understanding from years ago was that some planning had been done to find frequencies for a handful of low-power muxes for sub-metros across a city like Sydney. The idea was that nearby stations would share a mux (e.g. 2CCR and 2SWR).

I think this idea is alluded to in a previously linked CBAA annual report which lists a number of stations around the Eastern Sydney that would be a part of the 8D trial.

Of course this would require supporting legislation to move beyond a scientific trial license.

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Went up Mt Gibraltar today with my Sangean DPR-35 portable DAB+ radio. The Sydney 8D Scientific DAB+ test is receivable from the Mittagong lookout on the Gib. It is not receivable from the roadside pull off.

At the Mittagong lookout I was able to get the signal strength / quality up to 75% it still fluctuated depending on where you stood.

Sydney DAB+ 9A / 9B / 9C were received with 100% signal strength and quality.


Over at the Bowral lookout on the Gib there is still enough shielding to receive 8D Canberra, strength and quality similar to other dx trips.
The maximum signal strength and quality was received near the undercover picnic table.

Weather conditions up there today was mild for winter with a coolish breeze 17’c, but as I dropped down into the Sydney basin the temperature quickly jumped up to 25’c.

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It’s so mild that I’ve been opening my windows for the first time this warming season. We’re headed for 20C+ over the weekend.

Good to see that you can hear the 8D test up there. Obviously no chance from here, though I have yet to try the Sydney commercial muxes during intense tropo here. Need to dust off my own DPR-34 which is languishing in the side pocket of my car, and out of battery :smiley:

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BTW Braidwood fm was a mess at the Bowral lookout, RSR was at equal strength, as the car moved it switched between the two.

Also quite a bit intermod and mixing of 2ST and HFM, but not as bad as in Goulburn.

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