AM Radio interference - 96 130 TDI

[mike_k]

G'Day all,

Over the past few months I've been trying to isolate the cause of some intermittent radio interference occuring only on the AM side of the standard factory radio / cassette unit.

It sounds like a realy loud burst of static, and is intermittent - sometimes it wont happen for hours and other times it is almost continual. FM is fine, and the only other symptom that I have is that the indicators 'click' through the radio, and when the wipers are on I can hear a loud buzz in time with the wiper motor. (Both of these also occur on AM only)

The static also seems to be loudest when I've got my foot down on the accelerator, and dies away when I take my foot off - not a very useful feature!

Here's what I've done so far.......................

Fixed poorly terminated earth lead from battery to chassis to gearbox.

Installed new earth lead from chassis to engine block via starter motor mounting bolt.

Fitted bonding wires between bonnet and bulkhead, all 3 sides of ute tray to tray and one between the chassis and the tray. (She has an aftermarket steel tray)

Replaced condensor / suppressor at rear of alternator and cleaned terminals.

All of the underbonnet wiring looks to be in good condition - for everything.

Removed radio unit from mounting and cleaned it internally. (not very dusty either)

Checked all loom wiring to radio for security and condition - all OK

Checked antenna cable at radio end and antenna end - all fine :mad:

Anyone got any ideas?

I must be on the wrong track, thought I'd fixed it with the bonding wires but it still happens.

Next will be replacement of the radio unit, but if I can fix the current one I'd prefer to do that.

Interested to hear if anyone has had the same problem.

And before anyone asks why I want an AM Radio anyway, the footy season is about to start, it was hard to listen to the cricket over summer, and occasionally I need to hear the ABC Bushfire updates!:D

Over to the experts,

Cheers,

Mike.

[weeds]

i went throught the same and in the end it was the antenna it self

[mike_k]

Thanks for your reply Kelvin,

I knew I had missed something.:mad:

When I checked out the antenna, I found a rusty set of coax connectors with some dodgy wiring right up under the wing at the antenna base.

The antenna also looks a bit non standard as well - looks as if someone swapped it with the original and coudnt be bothered to run the cable through the bulkhead up to the radio. So they cut and joined the antenna cables to splice them together and then hid the join so it could get really wet and rust up. no insulation tape either.

So far so good, big improvement in reception. I'm going away this week with work, but I'll let you know if its fixed for sure when I get back.

Cheers,

Mike.

[mike_k]

Yes, Looks like it's fixed.

Thanks weeds, appreciate your tip.

A good exercise at the end of the day, now I've got a fully electrically bonded 130, with perfect earths and fully inspected wiring!

Also I can hear the footy again on AM.

Thanks to whoever it was who bodged up the antenna cable and hid it under the wing. :mad:

Cheers,

Mike.

[Xavie]

The indicators click through mine too and it's the latest model.

I get interference but have put it down to train lines.

Xav

[Utemad]

Good that you've fixed it.

As a rule if you get unwanted noise through your radio then check your antenna earth. Makes a bigger difference to AM than FM.