Radio interference

[jpsh120]

The radio reception when using MW is terrible and picks up interference from all electrical switches (windows etc) and it gets even worse when the tailgate is up. Is this a common problem that a new aerial will fix or something else??

[Skezza]

The radio reception when using MW is terrible and picks up interference from all electrical switches (windows etc) and it gets even worse when the tailgate is up. Is this a common problem that a new aerial will fix or something else??

OEM radio or aftermarket?

Petrol or a diesel?

What kind of interference? Loud staccato crackling, humming or white noise in the background?

What kind of aerial are you using? The standard bee-sting or an aftermarket one, like a stubby?

In answer to your question, possibly but not necessarily. A new aerial did help me, somewhat, on my old petrol Lupo, but there were other things I did that helped more. Getting MW to work with an aftermarket radio took me quite a long time on the petrol Lupo, lots of diagnosis, on my SDI Lupo hasn't been anywhere near as hard, but I too, get interference from electric windows and also the headlights. If it gets bad, quickly turning them off when it's safe to do so, and back on, seems to help a lot!

[jpsh120]

It is humming/crackling that then buzzes when electrics are working. When you lift the tailgate any reception you had goes altogether. This is using an aftermarket radio with the OE bee sting aerial, its petrol engined.

I'm considering a new aerial as it has seen better days and then maybe some supression if that doesn't work.

[Skezza]

It is humming/crackling that then buzzes when electrics are working. When you lift the tailgate any reception you had goes altogether. This is using an aftermarket radio with the OE bee sting aerial, its petrol engined.

I'm considering a new aerial as it has seen better days and then maybe some supression if that doesn't work.

Is it doing it all the time? Or only when using the electrics...? Also do you have a signal separation filter installed? I assume you do, because if you don't your MW signal would be borderline non-existent. What's the signal like with the engine turned off?

I had a 1.0E petrol with MW issues, and it took a surprising amount of effort to get it perfect, but I'll go through it. I did learn a lot about it though, and if your radio reception is ok with the engine off, and there's no noise on CD/USB/AUX mode on the radio, then it's almost certainly an earth issue that's being picked up by the antenna.

In order of what happened in my experience:

1. Replaced Bee Sting Aerial. Note: Do NOT fit a stubby, if you want good MW. I fitted a generic bee sting eBay job. This did improve my reception somewhat but I still had very loud staccato crackling, especially when accelerating.

Result: Slightly better quality signal when car was off, but still completely useless. All I could hear was constant noise when driving, with small periods of decent quality radio.

2. After several hours of testing for a bad earth, it turned out that the outer can on the signal separation filter wasn't earthed properly. In the short term, I fixed this by wrapping a jubilee clip round running a wire to one of the screws in the back of the head unit. Almost all noise was eliminated. Later, I replaced this with a brand new signal separation filter with the correct plugs on both ends, so I didn't need these silly adapters recommended by Halfrauds.

Result: The first time I could genuinely listen to MW Radio on an aftermarket stereo.

3. I lived with the little bit of crackling in the background for a long time as I figured this was just a result of MW radio. Anyway, I eventually got a misfire, that was caused by one my leads packing up. I replaced all four leads and in the process, eliminated the rest of the static issues.

Result: Perfect MW.

I'll be honest, I'm not convinced that noise suppressors will work in this case, although a ground loop isolator might work, don't hold me to that though. You've said your issue is with MW only, which means it's interference being picked up by the antenna only, which is usually caused by a bad earth or in rare cases a failing ignition system. MW is quite susceptible to noise, I assume you've driven under a bridge or a powerline, so you'll know that.

It doesn't sound like electrical interference which is where there is an issue with the alternator or battery charging circuit.

The noise generated by your electrical accessories such as windows is common. I have it on my newer Lupo. I'm yet to find out exactly what it is, but I've found the interference is nowhere near enough to affect me. It's normally a low hiss in the background as I wind the window down. Everything is clear.

I'm not 100% sure, but if my understanding is correct, fitting suppressors in your case will do absolutely nothing. Although it might help you solve the noise introduced from the electric windows, although even then I'm still not convinced it's not noise being picked up by your antenna.

Edited November 27, 2013 by Skezza

[Skezza]

If you get chance, record a video with audio, then post it up here. It should be fairly obvious what type of interference it is

[jpsh120]

Thanks for the info, I've only just remembered to check back on here!

So with the engine off, MW is just about audible, albeit with the constant humming in the background. If you operate a window then you get the sound of that electric motor through the speakers.

And as per my last post, opening the tailgate eliminates all reception.

FM reception is fine. I'll get a replacement aerial for starters and investigate this signal separation filter, I'm not sure what it looks like but I'll figure it out!

Thanks again for the info and if I don't make any progress I'll see about posting a video.

[Skezza]

Did you definitely fit a signal separation filter? Without one, you would get limited MW reception, barely audible, which is how you describe it. They make a massive difference.

[jpsh120]

Did you definitely fit a signal separation filter?

The car was purchased with the radio fitted so I need to check. I don't drive it very often but when I do, I usually want to be listening to Radio 5!

[jpsh120]

Just to be sure, are we talking about one of these;

http://www.ebay.co.uk/itm/Autoleads-PC5-52-Amplified-Car-Aerial-Antenna-ISO-Adaptor-/400616116992?pt=UK_Cars_Parts_Vehicles_Terminals_Cabling_ET&hash=item5d4694d300

It's listed as an amplifier but it looks identical to the picture I found when I googled 'signal separation filter'.

Thanks again.

[Skezza]

Yes. They're often labelled an aerial amplifier, incorrectly may I add. They're a signal separation filter. They act as a phantom power supply. Necessary for MW, and FM RDS. Not required for just FM.

[jpsh120]

Took some time today to fit this device to see if it made any difference and alas no. Assuming the power antenna feed from the head unit is suitable this thing made no difference at all. I think the aerial could be the culprit, not only does it look likeit h as seen better days, when I put my finger on the aerial socket on the head unit and turned myself into an aerial the reception was much better!

Any other thoughts or advice welcome.

[Skezza]

Took some time today to fit this device to see if it made any difference and alas no. Assuming the power antenna feed from the head unit is suitable this thing made no difference at all. I think the aerial could be the culprit, not only does it look likeit h as seen better days, when I put my finger on the aerial socket on the head unit and turned myself into an aerial the reception was much better! Any other thoughts or advice welcome.

It could be, especially with MW. The length of the aerial makes a massive difference with MW though, so touching the aerial socket, for me doesn't prove anything.

If you do replace the aerial, make sure it's a proper Bee Sting and not an aluminium stubby. You've got no chance of good reception with a stubby aerial. In the mean time, take the old aerial, and some wire. If it's insulated strip one end. Wrap the bare end of the wire around the thread of the aerial, then take the rest of the wire and wrap it round the aerial all the way to the top. Try it then. If it works, there's a good chance it's the aerial. If it doesn't, well then I think you might be barking up the wrong tree