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Intermittent DAB Signal Loss

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SS4

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Has anyone else noticed that DAB signal on the radio intermittently deteriorates? I am in the Birmingham area if it makes a difference, not far (relatively speaking) from the Sutton Coldfield transmitter.
It is probably not the placement since I've not moved the radio for months and it worked fine until a couple of months ago.

It was down this morning but is back up.
 
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Bungle73

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Has anyone else noticed that DAB signal on the radio intermittently deteriorates? I am in the Birmingham area if it makes a difference, not far (relatively speaking) from the Sutton Coldfield transmitter.
It is probably not the placement since I've not moved the radio for months and it worked fine until a couple of months ago.

It was down this morning but is back up.

Maybe try switching it off (I mean at the pug) for a while, then on again; sometimes I find that helps with my DAB clock/radio. It's an old computer trick, and since most electronic items these days are basically computers, it tends to work a treat with a lot of things.
 

WatcherZero

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What kind of radio is it? If a small one inside people cast radio shadows so people moving around the house will cause intermittent interuptions. If its in a car you can get odd reflections which interfere with the signal.
 

Lrd

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Have you tried re-scanning for stations as they may have changed frequencies slightly.
 

SS4

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What kind of radio is it? If a small one inside people cast radio shadows so people moving around the house will cause intermittent interuptions. If its in a car you can get odd reflections which interfere with the signal.

Pure Tempus-1
Pure Evoke 1-xt (x2)
A blue battery powered one I forget the name of
Two small portable radio running off batteries (bush)

Have you tried re-scanning for stations as they may have changed frequencies slightly.

Wouldn't that lead to a permanent loss of signal quality?

The signal has dropped about 30s ago
 

LE Greys

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Was there a motorbike going past? I ask because that affects the (hopeless) digital TV signal in Graveley.
 

michael769

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DAB signals are slightly more difficult to receive than regular FM so in some areas the reception of DAB can be problematic even where a good FM signal is received.

Unfortunately the only viable solution (other than moving the radio in the hope of finding a better spot) is to invest in an external DAB antenna - assuming the radio has a external input.

The Pure radios usually have very efficient receivers that cope well with borderline signals so if you are having problems with them your only options are the external antenna or switch to FM.

Unfortunately closeness to a transmitter is no grantee of a good signal as the frequencies involved work best with line of sight and the closer to the mast the more completely an inconveniently placed building can block the signal. If you are very close then you can experience problems with the signal being too strong causing signal overload issues.
 

SS4

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I don't understand why it'd work for years and then suddenly drop out. Is nobody else having this problem?
 

michael769

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I don't understand why it'd work for years and then suddenly drop out. Is nobody else having this problem?

The environment around us is not unchanging. Building works can create new obstructions, maintenance work can move antennae slightly, new equipment and introduce new sources of interference. In some cases the growth of trees and other vegetation is sufficient to cause problems to start (and indeed to become seasonal - though this is something that is associated with the relatively weak microwave signals used in satellite transmissions)

I am curious what you mean by "fading" fading is a phenomenon usually associated with MW and LW analogue transmissions where the reflection of signals off the Van Allen belts creates interference patterns that cause the signal power to rise and fall.

But this phenomenon does not affect DAB frequencies. DAB tends to operate in 1 of 3 states: Good reception, a horrible warbly mess, no reception at all. The constantly changing environment around us means that a signal at the boundary between two states will tend to move between them as the various influencing factors change - and the nature of digital transmission is that these transitions are much more obvious than with analogue.

Have you bought any new DECT cordless telephones recently? The cheaper models are notorious for causing problems with TV and radio reception in low signal areas.
 

SS4

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The environment around us is not unchanging. Building works can create new obstructions, maintenance work can move antennae slightly, new equipment and introduce new sources of interference. In some cases the growth of trees and other vegetation is sufficient to cause problems to start (and indeed to become seasonal - though this is something that is associated with the relatively weak microwave signals used in satellite transmissions)

I am curious what you mean by "fading" fading is a phenomenon usually associated with MW and LW analogue transmissions where the reflection of signals off the Van Allen belts creates interference patterns that cause the signal power to rise and fall.

But this phenomenon does not affect DAB frequencies. DAB tends to operate in 1 of 3 states: Good reception, a horrible warbly mess, no reception at all. The constantly changing environment around us means that a signal at the boundary between two states will tend to move between them as the various influencing factors change - and the nature of digital transmission is that these transitions are much more obvious than with analogue.

Have you bought any new DECT cordless telephones recently? The cheaper models are notorious for causing problems with TV and radio reception in low signal areas.

Nothing new. Not much has changed with regards to technology. Fading was a misnomer on my part, it's much more like the events listed in your following paragraph.
 

causton

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I have a DAB radio which I have on 'mute' when I don't use it as it takes about 1 minute to actually turn on. Most of the time the signal cuts out and goes into the 'warbly mess' that you get every 5-10 seconds or so... my uber-technical fix is to switch to the next channel and back and that fixes it! :P
 

DaveNewcastle

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There's 2 possibilities which come to my mind here.

As michael769 has noted, the signal strength and quality has to be good for DAB signals (stronger than for corresponding AM or VHF analogue broadcasts), and this is something can can be reduced for a variety of reasons. You didn't tell us if they rely on an external aerial or small indoor (or an even smaller one within the receiver) aerial. Both of these can lead to a loss in reception - external aerials suffer wind damage (cease to point in the correct direction, cable damage, water ingress, failure of mounting bracket);
indorr (or within the radio) aerials will suffer from new obstructions between the transmitter and receiver. From your username I'll guess that your nearest DAB transmitter is Emley Moor near Huddersfield. Has something appeared between it and you? That could be a new building, a power line, some roof insulation or the neighbour's kitchen appliances!).

The second possibility is equipment failure. If you've noticed the same loss on several receivers, then its definitely the signal path to your aerials that's the problem, but digital receivers do develop subtle faults which can degrade their reception.

Finally, are you aware that forum member Justin Smith is in South Yorkshire and has a business dedicated to broadcast aerials and systems? They will be able to come out with a signal strength meter to determine where the fault lies.
I did some work with one of Sheffield's radio stations for a while, and I did find that the hilly terrain created quite a few significant anomalies across the city, and the combination of a hill's attenuation of a signal with a building's reflection of the same but delayed signal could often create difficulties for listeners.
 

SS4

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As michael769 has noted, the signal strength and quality has to be good for DAB signals, and this is something can can be reduced for a variety of reasons. You didn't tell us if they rely on an external aerial or small indoor (or an even smaller one within the receiver) aerial.

Both of these can lead to a loss in reception - external aerials suffer wind damage (cease to point in the correct direction, cable damage, water ingress, failure of mounting bracket);
indorr (or within the radio) aerials will suffer from new obstructions between the transmitter and receiver.

My apologies, the aerials are internal insofar as they stick out the back of the radio and are about 30cm high so hardly external. I suspect that's a small indoor aerial

From your username I'll guess that your nearest DAB transmitter is Emley Moor near Huddersfield. Has something appeared between it and you? That could be a new building, a power line, some roof insulation or the neighbour's kitchen appliances!).

Me? I'm in Birmingham and according to this site my local transmitter is in Sutton Coldfield. I've not checked if anything has come up between it and me although it's possible.

The second possibility is equipment failure. If you've noticed the same loss on several receivers, then its definitely the signal path to your aerials that's the problem, but digital receivers do develop subtle faults which can degrade their reception.

Several radios are having the same problem so I'd expect it to be a problem between the transmission and me

Finally, are you aware that forum member Justin Smith is in South Yorkshire and has a business dedicated to broadcast aerials and systems? They will be able to come out with a signal strength meter to determine where the fault lies.

I'm in Birmingham though although I will if it gets worse (albeit more local than South Yorkshire). I was just wondering whether or not anyone else was having problems
 

asylumxl

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In my experience the "fading" affect is caused by a drop in signal strength which means the radio cannot match the bitrate of the broadcast. like what creates the need for buffering on streams online, but without the preloading.

I had issues with our DAB radio when we first got it, but by simply just moving it around the same room managed to find a nice sweet spot and have had no issues since. I moved the small indoor aerial around in various positions too.
 
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