Thread: 300Tdi RF Interference

It is usually the common rail that causes interference to the radio.

Have you considered shielding the engine harness by wrapping and some ferrites, perhaps it is acting as an antenna for the glow plug circuit. also ground all your movable panels like doors and bonnet with braided earth straps. It can't hurt and will improve the situation for when the Codan goes in.

Maarten, the glow plug relay is under the bonnet, and is quite quiet operation so i doubt it is this that is chattering. More possibly if you have a Disco, which I presume it is, is the voltage sensitive relay mounted near the steering column. Where did you take the power for the VHF from?

With regard to the Codan placement, I have a few D1 cutomers with their main unit in the rear load bay, and head unit on the dash, and causes no interference whatsoever. I have my Barrett in the RHR of the RRC and again, no issues at all.

Earthing is very important for the set and the antenna etc but I'm sure you already know this.

JC

Thanks JC,

Yes it is a D1. If the glow relay is under the bonnet, then it could be that my volt guages are also being affected by the stray RF (They are LCD digital guages)

The chattering relay seems to be somwhere near my right foot in the side quarter panel near the fuse box. The power for the VHF radio comes directly from my Aux battery located in front of the air filter box under the bonnet.

The cable from the aux battery is 10mm2 in a direct line from the battery to the underside of the passengers seat. I will try clipping on a torroid near the battery to see if it is going up that way, but I doubt it.

I don't think the relay itself is the problem, bur rather the control circuitry that drives it. For example.... I regularly service our Amateur Radio repeater up at the television broadcast site in town and every time I go up there, various relays chatter under the dash from the stray RF around the site.

I think the fix will be to place a torroid to the main input voltage leads of the offending control box hwatever and wherever that might be!! Could also be lack of adequate earthing somewhere..... somewhere seems to be the common denominator!!!

Will be fitting an Icom IC7000 and the 9350 autotune soon..... can almost hear the relays just thinking about it!!!

Regards
M.