Poor DAB reception on some channels - 2024 T6.1

[alan456]

We have a 2024 T6.1 Ocean with the optional Discover Media Pro Navigation System and the DAB cuts out so often on some channels it is unusable.

It is fine on Radio 1 but channels like Absolute Radio cut out for minutes at a time and then returns normally.

I know it is nothing I have fitted to the van because it did it on the drive home from the dealer when we collected it!

I do not believe that it is down to being in a weak transmission area because I have never had this problem with other cars. I have been a car dealer for 45 years so driven hundreds of cars over years so know what to expect.

I have another VAG car ( Cupra Born) and that does the normal drop out briefly as it retunes or I go through a small black spot but it has never dropped out for more than a second when driving all over the UK and Europe.

The dealer has tested the system and reckons the aerial/aerial amplifier are supplying a full signal to the radio so it could be a radio fault or more likely software. I presume they chacked for software updates but didn't ask.

Any ideas before I get stroppy with them?

Alan

 

[lohr500]

I have the same problem on some DAB channels. The main BBC Stations are OK, but some of the commercial stations drop in and out quite often.

I've never looked into it, but I wonder if they are on a different part of the DAB frequency band or not relayed from as many masts?

Had the same problem in my Subaru previously so I don't think it is unique to VW unless Subaru use the same radio supplier. (Or should that be infotainment supplier !!!!!).

 

[Perfectos]

My 2018 develop this some time ago, I presumed there was sone change to the transmission that caused the unexplained issue.

 

[Ryanrunsfar123]

Same here in our 2023 Ocean - drives me mad. Yet my other two cars (A Nissan and a Land Rover) driving exactly the same routes are fine on DAB. All I want is 6 music. Defo can’t rely on mobile signal these days as our network seems to be more and more useless every day.

 

[brcas64]

Same on a 2020. I put it down to degrading infrastructure and lack of investment.

 

[California Rob]

i noticed the same problem with the DAB stations but i put it down to travelling around the country more. I used to just re scan and it was ok for a while. The owners manual isnt very clear on how the tuning actually works auto tuning to the best signal etc. Ive recently downloaded the free rayo app which gives me most of the radio stations i enjoy.

 

[alan456]

Same on a 2020. I put it down to degrading infrastructure and lack of investment.

It's fine on my other cars so it is the Cali and not the transmission

 

[alan456]

Same on a 2020. I put it down to degrading infrastructure and lack of investment.

It's fine on my other cars so it is a Cali thing rather than infrastructure

 

[alan456]

Same on a 2020. I put it down to degrading infrastructure and lack of investment.

It's fine on my other cars so it is a Cali thing rather than infrastructure

 

[Perfectos]

@Hamid - Satnav Systems

Are you aware of this issue ?

 

[Rololux]

All BBC radio services are on the same DAB multiplex (also called ensemble), which is operated by the BBC and transmitted from BBC transmitters. Commercial stations are split between 2 other multiplexes, which are DAB+ (different standard) and are transmitted from Arqiva transmitters. All 3 muxes are in the same frequency band.

BBC uses higher bitrates, but less efficient encoding. Not sure about the relative signal to noise ratios, although I have seen some data that suggests commercial signals are around 4dB lower. It is fair to assume that the commercial transmissions push the throughput to the limit, which inevitably will reduce the reception margins. So this could be why commercial stations drop out first.

So this is likely to be an rf limitation of the Discovery media system, rather than a software issue. If it’s generic, could be down to the design of the aerial / rf cabling, or the receiver itself. If it only applies to some systems, could be a manufacturing problem. But either way, your Cali dealer will not be an rf expert, so will be unable to troubleshoot effectively.

Sorry not to be more positive, but it is unlikely that there will be a fix unless you can find a suitable rf engineer!

 

[alan456]

All BBC radio services are on the same DAB multiplex (also called ensemble), which is operated by the BBC and transmitted from BBC transmitters. Commercial stations are split between 2 other multiplexes, which are DAB+ (different standard) and are transmitted from Arqiva transmitters. All 3 muxes are in the same frequency band.

BBC uses higher bitrates, but less efficient encoding. Not sure about the relative signal to noise ratios, although I have seen some data that suggests commercial signals are around 4dB lower. It is fair to assume that the commercial transmissions push the throughput to the limit, which inevitably will reduce the reception margins. So this could be why commercial stations drop out first.

So this is likely to be an rf limitation of the Discovery media system, rather than a software issue. If it’s generic, could be down to the design of the aerial / rf cabling, or the receiver itself. If it only applies to some systems, could be a manufacturing problem. But either way, your Cali dealer will not be an rf expert, so will be unable to troubleshoot effectively.

Sorry not to be more positive, but it is unlikely that there will be a fix unless you can find a suitable rf engineer!

Thanks for the brilliant reply. It never occured to me that it could be an equipment limitation rather than a fault.

I have had lots of experience of DAB having been warranty clerk at a Vauxhall dealer for 20 years and virtually every reception issue was either aerial/amplifier or software related rather than design.

It looks like I will have to stop listening to the radio and stram instead!

Alan

 

[capt kirk]

also may not be relevant in your case but has caused issues in my van....
usb adapters plugged in near the radio caused my dab channels to become very poor, took ages to track it down to usb adapter for sat nav. moved it further away and fixed.

 

[brcas64]

You learn something new everyday on this forum.

 

[Perfectos]

All BBC radio services are on the same DAB multiplex (also called ensemble), which is operated by the BBC and transmitted from BBC transmitters. Commercial stations are split between 2 other multiplexes, which are DAB+ (different standard) and are transmitted from Arqiva transmitters. All 3 muxes are in the same frequency band.

BBC uses higher bitrates, but less efficient encoding. Not sure about the relative signal to noise ratios, although I have seen some data that suggests commercial signals are around 4dB lower. It is fair to assume that the commercial transmissions push the throughput to the limit, which inevitably will reduce the reception margins. So this could be why commercial stations drop out first.

So this is likely to be an rf limitation of the Discovery media system, rather than a software issue. If it’s generic, could be down to the design of the aerial / rf cabling, or the receiver itself. If it only applies to some systems, could be a manufacturing problem. But either way, your Cali dealer will not be an rf expert, so will be unable to troubleshoot effectively.

Sorry not to be more positive, but it is unlikely that there will be a fix unless you can find a suitable rf engineer!

Great response.

Why would a unit with no problem previously (5 years) seemingly develop a DAB (corrected) drop out issue ?

 

[capt kirk]

My dad dropped out a while back….really miss him

 

[secret lemonade drinker]

Perhaps as the UK government has been rationalising the DAB/DVB channels to make way for 5G prior to the 3G switch off the available bandwidth has become compressed meaning the bit rates and signal strengths have diminished.
Sounds good, probably utter clap trap but it is what one of my contractors told me when I complained about poor signal service on a site I work at.

 

[Rololux]

Great response.

Why would a unit with no problem previously (5 years) seemingly develop a DAD drop out issue ?

There are many reasons why this may be the case. It's not necessarily an equipment aging issue, although this is always a possibility. DAB operates in a very hostile rf environment, and it's all about margins. If the margin drops below a certain level, you will get no audio - there is no gradual degradation like with FM, or even satellite TV - it just stops. There is huge commercial pressure to squeeze the most out of any transmission network, and the more you try to squeeze into a fixed amount of space, quality will go down. Only around 50% of the data transmitted on a DAB mux is for radio services - most of the rest is for error correction - essential to provide robust reception, what with all the multipath, and interference from adjacent transmitters etc.. If the provider has reduced the amount of error correction in order to squeeze in more stations, then this reduces the margin.

I do not know the history of these particular transmissions, so I cannot say for sure that this is what has happened, but I am very familiar with other digital transmission systems, and the commercial pressures are often the same.

It should be noted that interference is also a possible reason for lack of reception margin. Interference can originate from a variety of sources - either in the wider rf environment or locally - i.e. within the van itself. DAB operates at around 220 MHz - I certainly don't know the California well enough to say whether or not there is anything capable of creating this frequency in the van, but I suppose it's possible. If someone out there has a suitable spectrum analyzer to hand, and fancies a poke around, I think we'd all be fascinated in the results!!

 

[Hamid - Satnav Systems]

@Hamid - Satnav Systems

Are you aware of this issue ?

Yes! Unfortunately it is a very common issue.

The reply from Rololux makes perfect sense.
The only thing I can add which may help is that owners should be aware of how much radio reception, specially DAB, is affected by anything else connected to a power source for example: a dash cam, radar/speed camera detector or mobile phone charger.
The drop in signal reception can be extreme, specially if using a low quality, poorly insulated 12V cigar lighter adaptor or similar.
Also, LED light bulbs can affect the reception so for example if you replace the interior lights with cheap LED ones, that will cause a poor DAB (and FM) signal as they will emit a lot of 'noise'.

Personally, I get around the issue by using Apps such as Global Player, BBC Sounds etc via Apple CarPlay (or AndroidAuto) to listen to radio stations.
Obviously this is not ideal either as a good data signal is required by luckily I have good cover on O2 where I live.
The other advantage of using an App is that you can skip tracks on live radio!

 

[Baldrick]

Plus one for the cigarette lighter USB issue in my experience the smaller they are the better they are at interfering with the DAB signal.
Because of the same issue as many others above I have also switched to listening via BBC iPlayer to get Radio 6 Music and enjoy previous shows whilst driving. Very much enjoying fast forwarding past the news and occasional dubious track.

 

[secret lemonade drinker]

Medium Wave Radio Luxembourg is best....works everywhere

 

[Wesel]

For those who have been young longer than others

 

[WelshGas]

For those who have been young longer than others
View attachment 135261

Available on Internet Radio.

 

[Rololux]

The actual original Radio Luxembourg transmitter, taken from the front of my old house a few years ago. I’ve moved now, but can still see it from my balcony.

 

[Rololux]

Even better photo, taken at sunset on 21st June, a few years ago. There are three masts in the array, but I lived too close to fit them all in one photo!