Drop in DAB signal when ignition switched on

[KJS]

Hi Guys,

I installed my RNS 315 DAB version today and also installed a Autoleads windscreen mount aerial.

Everything works fine with DAB but when I go to start the car the signal drops. This is only happening
when the ignition is turned on.

Can't figure out whats going on? On some of the VAG forums it is mentioned, if there is a USB adaptor plugged into
the 12V socket then this may cause interference. Checked on mine and nothing is plugged in.

Any ideas?

 

[micky moe]

Where did you get the power source from for the DAB aerial? Facebook me mate

 

[KJS]

Anybody? Not sure what seems to be the interference? Oddly only happens during evening times.
When ignition is off the signal is strong.

 

[Cartunes]

if you send me a wiring diagram, I can point you in the right direction! Sounds like the antenna might be receiving a 12v power supply up its co-ax, which would cut the signal if the antenna does not have the capacity to separate the radio signal and dc as in the case of an OEM VW Audi antenna.

 

[KJS]

Hi @Cartunes I think you are correct about the 12v power up the co-ax. Because the antenna works grand without connecting the power wire to a 12v ignition live I had setup.

Here is the wire diagram I found of RNS 315 online

Hopefully this helps?

 

[KJS]

Also @Cartunes I had the car scanned on friday and the radio was giving a open circuit error with the DAB aerial.

 

[Cartunes]

@KJS - that diagram doesn't help much as the antenna isn't shown, but I'm sure that's the problem area. Autoleads tech guru (used to be Dee after I left, but I think she has moved on) should be able to help.
Contact Details
Telephone
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Armour Automotive
Woolmer Way,
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[KJS]

Cheers mate I'll give them a bell today to find out....

 

[KJS]

@Cartunes here is a pin assignment for RNS 510 which I have been told is somewhat similar to the RNS 315. Dunno if this helps?

http://www.my-gti.com/529/volkswagen-rns-510-pin-assignments

 

[Cartunes]

Nah!

 

[KJS]

Tried calling them at break but no answer. Might have been busy.

Well I have sourced the issue to the problem. It seems to the headlights that is drawing the current off the aerial.
Basically I have autolights in my Leon and during evenings when the headlights came on, the signal would be lost.

It is working fine on sidelights. I have aftermarket HID lights (similar to these ones) in my car with build relays. Just wondering if they are drawing too much power then required?

 

[Cartunes]

It more like its interfering with the signal in the coax. Try changing the routing of the dab antenna cable, it's probably running past the light control unit. I have experienced that before.

 

[KJS]

Where would the light control module be? I mean driver side or passenger side as the cable is running from the LHS A pillar down the glove box and into the radio.

One thing though, the aerial is mounted near the autolight/auto rain sensor. Could this be something cause? Silly question

 

[Cartunes]

Yes, definitely. Try repositioning the antenna and cable first.

 

[Peje]

Yes, definitely. Try repositioning the antenna and cable first.

Electronics....I detest it. Hence me being a mechanical engineer Del will have you sorted in no time though

 

[KJS]

Yes, definitely. Try repositioning the antenna and cable first.

I will try to reposition the aerial over the weekend. Looking online it looks like, my aftermarket HIDs might be causing the problem.
One of the ballast may be faulty etc...although lights come onn perfectly.

Went and tested the DAB again with the ignition/headlights onn everything is working fine lol Signal is strong etc.

I will test again tomorrow and try to unplug one of the ballast and see if the signal comes back?

 

[Cartunes]

well? I'm salivating here,waiting for the next episode........

 

[KJS]

well? I'm salivating here,waiting for the next episode........

lol just went out in break and checked again. The DAB didnt work with the headlights onn, so disconnected one of each ballast and it still didnt come on. So disconnected both of them, and it worked. So looks like the HIDs are causing the issue.

 

[KJS]

Not sure if my test was conclusive, but will put the standard halogen bulbs back on and see if that also affects the DAB?

 

[Cartunes]

Not sure if my test was conclusive, but will put the standard halogen bulbs back on and see if that also affects the DAB?

I think we've found the culprit though..... where are the ballasts positioned? Keep the antenna wiring on the other side of the car from the ballasts at the very least! Maybe move the antenna to the rear screen? Position is important for EMI issues.

 

[KJS]

I think we've found the culprit though..... where are the ballasts positioned? Keep the antenna wiring on the other side of the car from the ballasts at the very least! Maybe move the antenna to the rear screen? Position is important for EMI issues.

Yup ballasts are positioned near the headlamps and antenna inside the cabin. On a second note, I am wondering if it is a earthing problem? Might run individual earth wires to each HIDs and see if it cures the issue?

 

[Cartunes]

Bad Earths are Bad, M'kay!!!! The biggest cause of interference on a vehicle. Apart from cheap Chinese HID kits........

 

[KJS]

Well it looks like, my FM is also getting affected
Time to throw the HIDs away and get me Halogen bulbs in

 

[Cartunes]

YAY! Go back to candles if that doesn't sort it. I've got a set from a Model T here in my desk at work if you want to test them.

 

[KJS]