I have a pre-facelift 2017 Octavia vrs

 

When I have the rear demist on, the dab radio says "no signal".

 

As soon as I have the demist off, the reception returns. 

 

Does anyone else's radio do this? 

 

29 minutes ago, Stonekeeper said:

 

Ah so it could be a damaged element in the rear screen? As I've only had the car a couple of days I'll query it with the Skoda dealership. 

If the car has no aerial and uses the rear screen it is a possibility.

 

Have you noticed if parts of the rear window don't demist?

 

It could also just be the quality of the earthing points of the hrw and aerial amp.

 

 

2 minutes ago, Stonekeeper said:

If the car has no aerial and uses the rear screen it is a possibility.

 

Have you noticed if parts of the rear window don't demist?

 

It could also just be the quality of the earthing points of the hrw and aerial amp.

 

 

The car has got the shark fin type aerial on the roof - but I think that's for GPS? 

 

It could be a bad earth too.

 

Thanks for confirming the signal drop out is not normal behaviour

 

It's a fairly common complaint on mqb cars. My mk7 my16 golf R does it. It has no sharkfin as the mib2 is only dab / Aa and car play. But with demister on, reception is worse.  No faults on aerials. There is an aerial in rear side panel cargo area window. Not sure which one that is. The screen heater may also be utilised as I have no protruding aerials with no GPS spec'd. 

A scan of the car would show if the aerial connection is compromised or not.

36 minutes ago, varaderoguy said:

A scan of the car would show if the aerial connection is compromised or not.

A scan with vcds?

Or would a basic obd scanner pick up a fault?

1 minute ago, N-C said:

A scan with vcds?

Or would a basic obd scanner pick up a fault?

VCDS or OBDeleven, basic scanners often don't pick up faults in non-powertrain systems.

10 hours ago, PetrolDave said:

VCDS or OBDeleven, basic scanners often don't pick up faults in non-powertrain systems.

Yep. Mine reports nothing, but a solid place to start. 

10 hours ago, PetrolDave said:

VCDS or OBDeleven, basic scanners often don't pick up faults in non-powertrain systems.

I'll get the dealership to investigate it. I won't get it booked in just yet - I'll make sure I'm happy with everything else on the car first. 

 

Speaking of which - the automatic front and rear wipers. I've got the option ticked in the settings menu. Do I need to have the stalk in a particular position for the wipers to activate? 

12 minutes ago, N-C said:

I'll get the dealership to investigate it. I won't get it booked in just yet - I'll make sure I'm happy with everything else on the car first. 

 

Speaking of which - the automatic front and rear wipers. I've got the option ticked in the settings menu. Do I need to have the stalk in a particular position for the wipers to activate? 

 

I would try position one which on older cars would have been intermittent, what used to vary the time becomes sensitivity of sensor.

On 02/01/2025 at 21:15, Stonekeeper said:

 

I would try position one which on older cars would have been intermittent, what used to vary the time becomes sensitivity of sensor.

Yes! Auto front wipe worked great on the motorway, thank you.

 

Does this position do auto rear wipe as well? 

On 02/01/2025 at 09:54, varaderoguy said:

A scan of the car would show if the aerial connection is compromised or not.

An update on the radio. Both FM and DAB reception are out with the rear demist active. 

 

A few elements on the rear demist are out. 

Both problems might be linked? 

 

 

You could fit a dab windscreen aerial to  solve the radio issue

 

https://kenwoodshop.co.uk/products/cxdab1?srsltid=AfmBOooPZommXdYUdO9WLKugFe_yKkR_gnEt8_pvGiOGRjzQNWJHvJg0

12 hours ago, N-C said:

An update on the radio. Both FM and DAB reception are out with the rear demist active. 

 

A few elements on the rear demist are out. 

Both problems might be linked? 

 

 

Could be. A few of my horizontal runs are also out.  So there is some commonality. I've never noticed the rear demist affecting my fm though. I'll have to double check. My car has no nav and no sharkfin or stubby aerial. Only one visible in the window, similar to demister lines above the rear guard. I've never investigated further.. 

 

Per @Stonekeeper you could experiment with an after market dan aerial. 

32 minutes ago, TheClient said:

Could be. A few of my horizontal runs are also out.  So there is some commonality. I've never noticed the rear demist affecting my fm though. I'll have to double check. My car has no nav and no sharkfin or stubby aerial. Only one visible in the window, similar to demister lines above the rear guard. I've never investigated further.. 

 

Per @Stonekeeper you could experiment with an after market dan aerial. 

 

They could share a common earthing point which would explain the loss of signal when hrw is turned on.

1 hour ago, Stonekeeper said:

 

They could share a common earthing point which would explain the loss of signal when hrw is turned on.

 

I've discovered the three lines in front of the brake light are the FM and DAB aerials. So they won't demist.

 

(The roof mount sharkfin is for GPS and mobile phone signal). 

 

So it could be a bad earth? There's an aerial amplifier. If this isn't getting power, then there's no signal. 

 

I'll get the Skoda dealership to investigate. They might have nudged something when the dash cam was fitted. 

6 hours ago, N-C said:

 

I've discovered the three lines in front of the brake light are the FM and DAB aerials. So they won't demist.

 

(The roof mount sharkfin is for GPS and mobile phone signal). 

 

So it could be a bad earth? There's an aerial amplifier. If this isn't getting power, then there's no signal. 

 

I'll get the Skoda dealership to investigate. They might have nudged something when the dash cam was fitted. 

If it was the amp it almost certainly would show up in a full scan.

 

There were some variants of the sharksfin which combined aerials if I am remembering correctly. But you would need to research visible identification. 

I've got this same issue on a 2021 MkIV Octavia Estate.  But it appears to be a reception strength issue rather than an on/off thing.

If I put the rear demister on while listening to some DAB stations they cut out completely, but others (BBC R4, for example) stay on fine.

Rear demister looks ok, no missing bars.  My car also has the sharkfin towards the back of the roof.

I thought it was maybe RF interference from the demister blocking the weaker DAB signals?

19 hours ago, Davva said:

I've got this same issue on a 2021 MkIV Octavia Estate.  But it appears to be a reception strength issue rather than an on/off thing.

If I put the rear demister on while listening to some DAB stations they cut out completely, but others (BBC R4, for example) stay on fine.

Rear demister looks ok, no missing bars.  My car also has the sharkfin towards the back of the roof.

I thought it was maybe RF interference from the demister blocking the weaker DAB signals?

It's definitely something to do with signal strength.  Here's two examples on slightly weaker signals

 

Cuts out on FM

https://photos.app.goo.gl/e9RbE8WzqJxLz8GU8

 

Cuts out on DAB

https://photos.app.goo.gl/fTT93YpzZzXnBUrf8

 

I'm wondering as other people have mentioned, it's something to do with a bad earth on the aerial amplifier?

 

If it was interference, wouldn't I still hear the FM radio station, but with interference?

An update on this. The rear screen was replaced under warranty. The lines work, and the radio seems fine.