C6 RT3 very poor radio reception

[jamescarruthers]

My C6 has never had the best radio reception in the few years I have had it now. It has gotten worse so as to be un-listenable now.

It can only pick up the strongest of stations and seems to be even worse with those lower down the FM range. What it can pick up it full of static and the indicators do seem to influence it as the hiss gets better when one is illuminated! AM is just as bad-- I tried out of desperation on a long trip!

Is this likely to be a head unit needing repair or is there a magic box that does radio signal amplification?

[GiveMeABreak]

It’s more likely to be the aerial assembly, amplifier unit James.

One way to tell is to get a cheap aerial with Dakar from the bay of evil and connect this into the relevant FM sockets at the rear of the head unit and stick the aerial in the dash temporarily. If there’s an improvement it’s likely to be water ingress into the aerial assembly. If no improvement, and you’ve checked the rear connections, then it may well be the internal tuners.

This is similar to the GPS antenna when testing the roof aerial out and the same applies, - if the satellite numbers improve, its indicative of the aerial assembly again.

[jamescarruthers]

It’s more likely to be the aerial assembly, amplifier unit James.

One way to tell is to get a cheap aerial with Dakar from the bay of evil and connect this into the relevant FM sockets at the rear of the head unit and stick the aerial in the dash temporarily. If there’s an improvement it’s likely to be water ingress into the aerial assembly. If no improvement, and you’ve checked the rear connections, then it may well be the internal tuners.

This is similar to the GPS antenna when testing the roof aerial out and the same applies, - if the satellite numbers improve, its indicative of the aerial assembly again.

Thanks Marc. The C6 doesn't seem to have a roof aerial like my C5 did. Where would this unit be on the car?

[GiveMeABreak]

Ok, so here's what I have on the system James:

Aerial diagram

(1) Radio Aerial
(4) Aerial Cable
(5) Aerial Cable
(6) Aerial Cable
(20) Aerial Switching Unit
(25) Filter for Aerial
(30) Impedance Adaptor


This is the 'FUBA' Diversity Unit

(21) RT3 audio/telephone.
(22) FM2 radio aerial.
(23) FM1/AM radio aerial.
(24) Diversity unit.
(c) ISO connector.
(d) FAKRA connector.
(e) 3-way yellow MQS connector.
The diversity unit is used mainly by the twin tuner function.

The diversity unit makes it possible to obtain a better quality of reception via the intermediary of two radio aerials:

• The second aerial continuously searches for a better reception frequency than that received by the first aerial
• The diversity unit selects the best frequency and transfers it to the RT3 radiotelephone

The diversity unit is located under the glove box (left hand drive vehicle).
The diversity unit is located behind the glove box (right hand drive vehicle).

(21) RT3 audio/telephone.
(22) FM2 radio aerial.
(23) FM1/AM radio aerial.
(25) Dual-function aerial (GSM/GPS) located near the dual-function rain and brightness sensor.
(26) Radio aerial adaptor.

[jamescarruthers]

Thanks for all this. By the magic of C6ness, reception has worked perfectly for about six months now after a year of not working!

[jamescarruthers]

I have finally worked out what was causing this. Once of my DRLs went out so I switched them off in the settings screen-- the radio had perfect reception until the automatic lights kicked in.

So, I have worked out that the DRLs, sidelights, headlights and brake lights all cause the radio reception to be terrible and have a load of interference.

Has anyone got any ideas where to start or maybe an idea of a component likely to have failed?