Radio Reception Dissapears When Put In Reverse??

[alkyz89]

wierdest thing happens in my car but never really paid much attention as i hardly sit in reverse...

but was wondereing if it was just my car or a common problem??

so basically ill be listerning to the radio with perfect signal, then when i select the reverse gear itgoes so crackley you cant hear the station... any1 else suffer the same problem??

[SeanW]

Nope...can't say I have...

Wonder if there's a wee earthing problem?

[frostman83]

My zetec reception Is terrible all round. Think yourself lucky! Lol

[vibeone]

I suffer from this, but only since I ran cables everywhere for 1) parking sensors 2) reversing camera 3) separated DAB aerial.

It seems like its the cables from the camera that has goosed mine, though the sensors had a similar effect.

Have you got sensors on yours?

[alkyz89]

No sensors... Although I plan to fit them soon so might have the opposite effect lol but I still don't understand how It would effect the signal unless you had a wireless set up that would interfere with the reception... Any brainiacs out there fancy shedding some light on the subject??

[vibeone]

Badly shielded cables running next to each other (in my case)

[Stoney871]

Try fitting some ferrite cores around the aerial cable.

This can help to reduce RF wash (that is the likely problem you're having).

[Andy H Dibley]

Can I take a guess that you fitted a Cree LED reversing light?

[alkyz89]

Haha I've got 2 Cree reverse lights lol is that the problem?

[Andy H Dibley]

I believe so. I had no problems with radio reception before, installed a Cree bulb, lose signal when the bulb is on.

Took the bulb out all is well again.

I think the electronics in the bulb aren't all that smart when it comes to RF interference.

[Stoney871]

Could be a good place to try a ferrite around the wires there and see if it helps?

[Andy H Dibley]

It really depends what's causing the interference.

If the bulb is badly shielded it could be oscillating from inside the casing and causing it to be picked up by the aerial, if its just poor design it could be radiating down the wires feeding the bulb, in which case yes, a ferrite core might help.

[frostman83]

Could this be the same with a interior light led ? It glows on all the time so could it interfere?

[Andy H Dibley]

It's all based on how well or poorly the design engineer was who designed the power supply module for the LED. It has to step down the 12~ VDC down to about 2.5VDC while also limiting the current.

Do a quick google search on Cree LEDs and Radio Interference.

[alkyz89]

cheers for the replies people... not to sure how a ferrit what improve my radio signal i thought they were just good for sending down rabbit holes....

just kidin what are ferrires, how do they work and how are they installed??

thanks again!!

[Stoney871]

Ferrite cores help to stop RF signals from electronic devices interfering with other systems.

If you've ever had a phone charger/USB cable/PC screen cable with a cylindrical bump on it then that is a ferrite core.

Easy to fit, they come in a clip on sleeve.

To stop them slipping around put a small cable tie either side of them.

http://pages.ebay.com/link/?nav=item.view&id=170920064420

[alkyz89]

do they come in different sizes to fit different cable diameters? and where abouts on the cable would i fit it and on what cables lol

[Stoney871]

They do come in different diameters.

I'd recommend one on the aerial cable as close to the connector on the aerial mount above the courtesy light and another one right before the connector into the rear of the radio.

[alkyz89]

nice one geez ill look into it

[Andy H Dibley]

Ok, I'm going to chime in here as I've got a fair amount of experience dealin with RFI being into Amateur Radio.

Firstly, yes a ferrite core will stop RFI in certain situations, most typically on I shielding cables such as twin speaker cable or power leads. What in shielded means is that there is no physical or electromagnetic desperation from the signal conductor to the outside. A sheilded cable typically has a mesh gauze or a solid wrap of tin foil like material. This wrap stops unwanted RFI getting into the signal conductor.

An aerial lead, typically know as a coax, is shielded. If you remove the plug you'll see you have a centre pin and then a cup around the outside which slides over the mating part. This outside cup is the connection for the shield.

Secondly, ferrite cores won't stop this interference if the LED Bulbs electronics are wideband oscillating. If the power supply is just shoddily designed like that there is little you can do other than throw it away, as it will be propagating a signal that the aerial is picking up. No ferrite core will be able to distinguish between Radio 2 and a LED power supply I'm afraid.

Since this topic has come up, I've been doing a little testing. My reverse light only makes a noise when I'm at work which is a notorious weak signal area for radio 2. At my house the signal is pretty good and I can barely notice it. This shows the radio does have a fairly good rejection of unwanted signals and that the LEDs power supply isn't a huge signal, it's only noticeable when regular FM reception is low or weak.

You can spend rediculous amounts of money on buying Ferrite bits and pieces but in my honest opinion and having one fitted in my car, I would just leave it or replace with a regular bulb. I know whenever I'm reversing I have more things to worry about than whether I can hear Simon Mayo ;-)

[alkyz89]

Tbh I've noticed it's only in areas with poor signal anyways like reversing out the garage... And how long do we spent in reverse... I just wanted to know if it was just my car is all and if there was a simple solution... Great explanation though, cheers for that, and all the others comments aswel..