DAB radio reception

[liffy99]

I've DAB radio in my S4(B8) along with MMI 2g high and B&O stereo. Outside my house in a small Somerset hamlet I can tune in quite happily all day long, across a variety of stations.
But when I'm out driving it's a different matter. The reception, on ALL stations simultaneously, comes and goes all the time. It's not like the sound gets gradually worse or starts to slowly fade, the sound is either there, or not, within the space of a few seconds, or metres.
It seems to be geographically related, for example I get nothing on large parts of the M5 through Devon and a few miles north of Bristol, patches around Glastonbury and Street are met with silence, and there are plenty of other examples.
I can't see any relationship to proximity to buildings, hills, landscape changes, power lines or anything.
So I'm unsure as to whether the problem is in transmission ( is DAB radio signal transmitted on crazily tight beams with many, many gaps) or is it my car (for example could the car's reception be so borderline that any fluctuation in the transmitted signal causes immediate loss).
I'm not talking short Term dropouts here - reception can disappear for seconds or minutes at a time.
What experiences have other. DAB users had ?

[stu]

I have a courtesy 2014 A5 at the minute and the DAB is disappointing. As you say, cuts out for minutes at a time for no reason. Infuriating. And FM doesn't cut it for me any more unless I want a good dose of the news - I quite Radio 4 for that.

I can't wait to get my own car back. I listen to BBC 6 Music all day long in it using a Bluetooth stereo input and my phone. I have to be in properly remote/mountainous areas before the Three data cuts out. Honestly, a millions times more reliable than shitty DAB. Where I drive, at least.

Does your car have a BT stereo input?

[PetrolDave]

DAB reception is patchy at best in many cars as the national coverage isn't good enough yet (despite what the BBC and Ofcom claim).

I have an aftermarket stereo in my non-Audi and get 100% coverage on FM but DAB suffers dropouts several times a day on my 6 mile commute (in the urban area of Southampton where coverage is supposed to be 100%).

[liffy99]

I can understand patchy, but I go from perfectly adequate reception to nothing within 20 or 30 metres. Is this normal ?

[stu]

I can understand patchy, but I go from perfectly adequate reception to nothing within 20 or 30 metres. Is this normal ?

Yes.

It's quite disconcerting in the A5 - there's music, then ~quarter second wall of static then silence. It fades back in nicely when the signal returns ten metres further down the street.

As Dave says the coverage is so rediculously thin that it just does this. And the way that DAB is broadcast means you don't just get weak/fussy sound: it goes from perfect to zero.

I read somewhere that more conspicuous aftermarket aerials help but I don't think I'd bother.

[HYFR]

My Land Rover never drops signal

[stu]

My Land Rover never drops signal

Maybe it's an Audi thing then. Whereabouts are you? London?

[HYFR]

All over! 23k miles and it's a 63 plate

[Timster]

My Land Rover never drops signal

That’s because you’re listening to Medium Wave Dave.

[PetrolDave]

I can understand patchy, but I go from perfectly adequate reception to nothing within 20 or 30 metres. Is this normal ?

Yes, it's an effect called destructive interference where two or more radio signals (e.g. direct from the transmitter and reflected off a building) combine to produce zero signal. Given that the wavelength of a DAB signal (approx 200MHz) is 1.5metres you can go from strong to zero signal in a few metres.

Under other conditions you get constructive interference to produce a stronger signal...