Colin Stamp wrote on 29/03/2006 19:05:

It's not just the frequency that's different. I get the impression
that the field-strength is a lot weaker for DAB too, so you do need a
high quality aerial to make sure you're not wasting any precious dBs
on a crummy downlead or whatever.

Fair enough, but I don't see anything on most of these passive antennae
that would make them perform better than their FM equivalents.

You can get splitters that attempt to give you a DAB signal from an FM
aerial, but others have said the performance is crap.

I'd expect so, splitting a passive signal isn't a particularly good idea
at the best of times, let alone from an aerial that isn't ideal at that
frequency. Both my cars have active rear-screen aerials so that's not an
option (not that I'd have gone down that route anyway).

I've got a Pioneer, amplified roof-mount DAB aerial on my car and I
get two muxes reliably in Milton-Keynes. I'm not sure if that's good
or not...

Mine is a JVC add-on box, and it came with a passive stick-on roof
aerial that I used on my old Audi which worked most of the time, but it
dropped out going under extended motorway bridges that barely affected
FM reception. It's pretty obvious the DAB signal strength is woefully
inadequate for reliable reception in the presence of obstructions,
significantly worse than FM. Coupled with the poor bitrates and even
worse codec it's no wonder the adoption rate is so poor - I'd say it's
now a dying technology and will probably remain a niche product until a
successor comes along.

Back on topic, a through-roof mount should provide at least as good a
signal as the supplied aerial due to the ground plane, and an amplified
aerial wouldn't benefit my DAB box as it's not designed for one
(probably does some internal amplification). I might just go for one of
the "proper" DAB aerials as suggested by the other posters in this
thread, begrudgingly forking out the £20-something - still a lot better
than the common price which is closer to £40!

Paul.

On Thu, 30 Mar 2006 16:26:07 +0100, Paul Morgan
wrote:

Colin Stamp wrote on 29/03/2006 19:05:

It's not just the frequency that's different. I get the impression
that the field-strength is a lot weaker for DAB too, so you do need a
high quality aerial to make sure you're not wasting any precious dBs
on a crummy downlead or whatever.

Fair enough, but I don't see anything on most of these passive antennae
that would make them perform better than their FM equivalents.

You can get splitters that attempt to give you a DAB signal from an FM
aerial, but others have said the performance is crap.

I'd expect so, splitting a passive signal isn't a particularly good idea
at the best of times, let alone from an aerial that isn't ideal at that
frequency. Both my cars have active rear-screen aerials so that's not an
option (not that I'd have gone down that route anyway).

I've got a Pioneer, amplified roof-mount DAB aerial on my car and I
get two muxes reliably in Milton-Keynes. I'm not sure if that's good
or not...

Mine is a JVC add-on box, and it came with a passive stick-on roof
aerial that I used on my old Audi which worked most of the time, but it
dropped out going under extended motorway bridges that barely affected
FM reception. It's pretty obvious the DAB signal strength is woefully
inadequate for reliable reception in the presence of obstructions,
significantly worse than FM. Coupled with the poor bitrates and even
worse codec it's no wonder the adoption rate is so poor - I'd say it's
now a dying technology and will probably remain a niche product until a
successor comes along.

You might well be right, but there's a few years in it yet. If they
replace it, I expect the codec will improve but the bitrates will
probably get lower still. They've already decided that the number of
services is more important than the sound quality.


Back on topic, a through-roof mount should provide at least as good a
signal as the supplied aerial due to the ground plane, and an amplified
aerial wouldn't benefit my DAB box as it's not designed for one
(probably does some internal amplification). I might just go for one of
the "proper" DAB aerials as suggested by the other posters in this
thread, begrudgingly forking out the £20-something - still a lot better
than the common price which is closer to £40!

Yep. The ground-plane made a huge difference on mine. My JVC head-unit
could barely pick anything in the shed when I tried it out with the
Pioneer aerial un-mounted. It was much better when I clamped it to the
side of a foot-square ally sheet. It's fine in the car.

I agree that an amplified one isn't for you though. With no power, the
amplifier will attenuate the signal, so it'll be much worse than a
passive one.

Cheers,

Colin.