OT: Bit wet yesterday, knocked out DAB reception completely.

[Andrew]

My new Denon DM41DAB refused to pick up any DAB stations yesterday while it was chucking down with rain.

Today they are sort-of back to normal but noticibly 'quieter' than the same program on FM. Getting better as the sun warms and dries out the roof (FM dipole in loft).

When the roof is fully dry, it is very good, even on DAB and DAB+. Better on DAB than the previous 2006 Onkyo version in fact, I'm quite impressed with it. I can switch between FM/FM Mono/DAB/ Optical 1/Optical 2/CD/Bluetooth (yuk) at the press of a button on the remote. Optical 1 takes the output from my PC sound, and when I can find an SPD/IF optical cable 2.5 metres long I'll connect my Samsung tv to it as well. (*)

A couple of reviews of this unit have mentioned very poor radio reception, which makes me suspect they are not in a very strong signal area and/or are using the supplied 'dipole'.

I'm definately going to make one of those dipoles in a length of kitchen waste pipe next year when it is warmer.

(*) I have read somewhere that once an optical digital cable exceeds 2 mtres in length, you need a good quality one.

[tony sayer]

In article <qsvv2d$njp$ [e-mail]>, Andrew <Andrew97d- [e-mail] scribeth thus

If i were you I'd fork out a few quid on a decent outdoor aerial and if it does look as if your in a bit of a reception hole mail me over your address if you want and I'll look that up.

Have a look on the Blake aerials website they do a good three element FM aerial for around 29 quid a good investment:)

As to optical cables don't now who said that these things are usually fine over quite some lengths they drive them over 10's of miles in comms nets!

[Brian Gaff (Sofa 2)]

Well dab usually goes boiling mud before it goes away completely. Could it be its got a squelch control that is set a bit higher than it should be? Brian

[Brian Gaff (Sofa 2)]

FM aerials with multi arrays are only good on fm, they kind of work cos they are outside on dab and as was mentioned in the previous thread, the lengths are all wrong. As an aside. I have a short wave band on one of my stereos and some broadcasters say they are on another frequency on DRM, now can any mainstream receivers actually decode this medium? Brian

[Roger Hayter]

I suspect that the ones used for audio are little more than crude plastic light guides.

[Andrew]

Brian, I got nothing at all on DAB.

Receiver just displayed "No Service".

Now it's back to normal.

For Bill,

I took another look at that strange free standing mast and the 18 element contract C/D aerial has been replaced by a wide-band job of similar length, on top of a long 2 inch diam pole, mounted on top of the mast. Bizarre.

I'll take a photo and try and post it somewhere.

Andrew

[Dave Liquorice]

Yeah but they'll be single mode and proper fibre and fairly pokey lasers.

Domestic S/PDIF Optical is just a plastic light guide in multi-mode, not even sure it uses laser light. The theorectical max distance is

10 m.

[Martin Brown]

Get used to it. That is all you can ever expect with DAB. Even satellite feed is more robust wrt to signal loss only occurring in the heaviest thunderstorms storms with the thickest clouds. Rain and leaves on the trees and you can pretty much forget DAB. Internet radio is the way forward now and you can get worldwide reception and live concert content not broadcast anywhere else.

There should be a sensitivity rating for full FM stereo decoding and acceptable DAB error rate. When there isn't enough signal FM degrades gracefully to mono and then to white noise whereas DAB degrades to the announcer gargling with mud with ultrasonic clicks and pops.

Most of the losses in an optical cable occur at the interfaces between the couplers and the cable. I have known one or two high end pieces of kit that are tetchy about which opto cables they will work with but more because of alignment issues an poor mechanical tolerances on the cheapest and nastiest interconnects. You do not need snake oil.

[tony sayer]

In article <qt0fdj$go3$ [e-mail]>, Brian Gaff (Sofa 2) [e-mail]> scribeth thus

Multi element arrays are quite good for DAB Brain tho not ideal but the way DAB works with OFDM it doesn't make much odds.

A bit of multipath on DAB isn't a bad thing:).

Don't think may are on DRM as yet it isn't really a broadcast standard that every ones agreed on.

[tony sayer]

Yes quite probably, we had a few of them daisy chained up once seemed fine!..

[Terry Casey]

But FM reception isn't his problem, so why install a new FM aerial for DAB?

Presumably his existing FM aerial is horizontal - needs to be vertical for DAB.

Also, an FM aerial is tuned for the wrong band - surprise, surprise!

A vertical DAB aerial (ie: one tuned for DAB!) will perform much better.

His FM aerial will be directional (assuming it is horizontally polarised). How do you know his local DAB transmitter is co- sited with the FM one?

[tony sayer]

In article [e-mail]>, Terry Casey [e-mail] scribeth thus

Have found that an FM aerial does work very well with DAB odd as it might seem, so i bet a decent outdoor FM aerial will sort the DAB reception out!.

In most places theres enough polarisation skew for it not to matter that much.

And i did ask him to say where he was but nowt heard as yet!

Besides he might need FM for high quality listening;)..