DAB - suddenly almost zero reception

[cria]

good advice . That close to Crystal Palace an indoor aerial should be fine ...

So all NA needs to do is cycle to Crystal P, listen live to the football match, pitch a tent and listen to his Dab radio in all its glory and scout for a house to buy

[Serial_Apologist]

So all NA needs to do is cycle to Crystal P, listen live to the football match, pitch a tent and listen to his Dab radio in all its glory and scout for a house to buy

Would that be a criagenic solution?

[mikealdren]

So all NA needs to do is cycle to Crystal P, listen live to the football match, pitch a tent and listen to his Dab radio in all its glory and scout for a house to buy

Sadly there are some DAB blank areas around Crystal Palace as I find when I drive around there.

[cria]

Sadly there are some DAB blank areas around Crystal Palace as I find when I drive around there.

He's only got to ask the estate agent before he buys the house

[mikealdren]

Yes, estate agents are great sources of reliable info........

[oddoneout]

He's only got to ask the estate agent before he buys the house

That would up the blank area count...DAB wots that. Radio 3 - wots a radio ...

[Nick Armstrong]

It could be that the 'front end' of your radio is being affected by a local source of radio frequency radiation - either because the radio's front end is 'wide open' (insufficient filtering) or the local source is 'dirty' (insufficient control of the bandwidth of the emitted signals). Are you aware of any new equipment (e.g. a router) which has been switched on or moved recently? (Could be your own or a neighbour's.) Alternatively the signal might be being shaded by a new structure - is any building work going on nearby?

It would be interesting to know whether the effect is common to both BBC and commercial multiplexes, as they use different frequencies, which could be affected differently in the two scenarios. Also on some transmitters the multiplexes are of different strengths. If you tune to a commercial station do you get the same effect?

Interesting, thanks. To my knowledge no new equipment or building structures entered the vicinity between the DAB signal being perfect and near-zero… A couple of buildings were scaffolded not far away quite recently but a least a few weeks before this turn of events.

The radio is permanently on R3 … I’ll check other stations.

[Nick Armstrong]

It would be interesting to know whether the effect is common to both BBC and commercial multiplexes, as they use different frequencies, which could be affected differently in the two scenarios. Also on some transmitters the multiplexes are of different strengths. If you tune to a commercial station do you get the same effect?

Further to earlier reply, very interestingly a lot of other (commercial) stations remain at full strength with excellent reception!

All the BBC stations are at minimal levels (plus a few others - inc Classic FM… )

So Voice of Islam or Absolute Rock it is…

Or JazzFM is still top notch sound…

What d’ya reckon, Mr Slater? I suppose this eliminates local obstruction or a ‘dirty front end’ (or any fault in the radio)…

[Cockney Sparrow]

I've had three DAB portables (a Pure Bug still serves as the bedside radio alarm). They all had an aerial at the back which unscrewed (with a small adjustable spanner).
What model are you using? (PM me if you want). If I can find reference to the aerial being of this type, then you might want to consider unscrewing the aerial and brightening with light pressure (sandpaper, scratching) any metal contact areas, to see if that improves the connectivity and signal on re-assembly.

In Scotland, in a relatives second home, and on holiday visits missing Radio 4 (BBC Scottish channel was the one available) we bought a DAB radio, I unscrewed the aerial and replaced it with one made of twin wire, routed up the wall in a shelf support and to the ceiling, then split at the end and drawing pinned to the ceiling - which got us the signal in the kitchen, where the radio had to stay. If you, Nick A, get to the point you think any of that might be useful, I could retrieve from memory and elaborate.

[Andrew Slater]

Further to earlier reply, very interestingly a lot of other (commercial) stations remain at full strength with excellent reception!

All the BBC stations are at minimal levels (plus a few others - inc Classic FM… )

So Voice of Islam or Absolute Rock it is…

Or JazzFM is still top notch sound…

What d’ya reckon, Mr Slater? I suppose this eliminates local obstruction or a ‘dirty front end’ (or any fault in the radio)…

The results of your investigation might eliminate local obstruction, unless it's frequency-sensitive (unlikely), or if the BBC and commercial signals are coming from different transmitters in different directions. The possibility of a local interfering source isn't eliminated, as it could well be emitting more at the BBC frequency. (It was the emitting device which I thought might be 'dirty', not your radio's front end! )

If you could PM me with your location I could try to determine where the transmitters of the various DAB signals you are receiving are likely to be. The effect on Classic FM is surprising as it's usually on the commercial multiplex. It's recently changed to DAB+, so if your radio isn't DAB+ -capable, or you haven't re-tuned it this year, CFM will be VERY quiet! When you say in post #4 that you've 'rebooted' the radio, do you mean you've re-tuned it? If not, that's definitely worth a try before going any further. Otherwise, might you be able to hunt through the menus and find which multiplex you are receiving CFM on? I would expect it to be "Digital One".

[Nick Armstrong]

Thanks to Andrew, the source of the issue is now clear:




DAB reception of BBC stations is now restored to full strength as per the indication there (although the fault manifested itself on 9 February rather than 12th as stated on that page).

I’ve bookmarked the very useful site

https://ukfree.tv/radio/prediction

in case of further problems.

.

PS Classic FM is still unavailable … which is a bonus (it’s not a DAB+ radio)

[Dave2002]

The effect on Classic FM is surprising as it's usually on the commercial multiplex. It's recently changed to DAB+, so if your radio isn't DAB+ -capable, or you haven't re-tuned it this year, CFM will be VERY quiet!

Is that a euphemism for inaudible? I would expect that an original DAB set would not be able to decode DAB+ signals at all - though I might be wrong. I thought that was the point of the advance notification from CFM about the changes which happened recently.

Assuming that the CFM channels have been "updated" as per the notification, then presumably some older DAB sets will now either not detect CFM at all, or if they do detect a carrier, will not actually produce any audible output.

I hadn't thought to check, but will do shortly. If CFM is still available on our Denon kitchen set, that would indicate that the set is DAB+ capable - which I think was is/was as per the specification.

Looks as though the original "mystery" has now been solved. We have a few other DAB sets from various times in the last decade or so, so it would make sense to check now if they can receive CFM and hence are DAB+ capable.

[Andrew Slater]

The effect on Classic FM is surprising as it's usually on the commercial multiplex. It's recently changed to DAB+, so if your radio isn't DAB+ -capable, or you haven't re-tuned it this year, CFM will be VERY quiet!

Is that a euphemism for inaudible? I would expect that an original DAB set would not be able to decode DAB+ signals at all - though I might be wrong. I thought that was the point of the advance notification from CFM about the changes which happened recently.

Assuming that the CFM channels have been "updated" as per the notification, then presumably some older DAB sets will now either not detect CFM at all, or if they do detect a carrier, will not actually produce any audible output.

I hadn't thought to check, but will do shortly. If CFM is still available on our Denon kitchen set, that would indicate that the set is DAB+ capable - which I think was is/was as per the specification.

Looks as though the original "mystery" has now been solved. We have a few other DAB sets from various times in the last decade or so, so it would make sense to check now if they can receive CFM and hence are DAB+ capable.

Yes, by VERY quiet I meant not audible. On my non-DAB+ - capable set it shows as 'station off-air'. I think it will continue to show this until you carry out a 'prune' operation. Thereafter CFM will presumably just not feature in the list of stations.

[Andrew Slater]

Thanks to Andrew, the source of the issue is now clear:




DAB reception of BBC stations is now restored to full strength as per the indication there (although the fault manifested itself on 9 February rather than 12th as stated on that page).

I’ve bookmarked the very useful site

https://ukfree.tv/radio/prediction

in case of further problems.

.

PS Classic FM is still unavailable … which is a bonus (it’s not a DAB+ radio)

The historical fault is now showing on the BBC site, linked by Cockney Sparrow. I suspect that the published fault duration actually covered the repair period, when the commercial multiplexes would also be on low power to facilitate the works. The authorities are quite slow at responding to complaints, for understandable reasons: many so-called 'faults' will probably have their cause at the receiving end or between the transmitter and receiver, rather than at the transmitter itself. I found it slightly frustrating to convince them of a subtle 'drop-out' fault with the Holme Moss FM transmitter a few years ago until somebody else situated diametrically opposite the transmitter from me also complained of the same fault, at which point they took the complaints seriously, and repaired the fault quite promptly.

[Old Grumpy]

.

PS Classic FM is still unavailable … which is a bonus (it’s not a DAB+ radio)

I thought CFM would disappear from our car radio...


...but lo, it is still there so we must have a DAB+ compatible receiver - the "infotainment" display still says DAB though - no sign* of a plus, though!



* Pun intended