HF Radio interference GU Patrol litre diesel

Submitted: Tuesday, Sep 05, 2006 at 14:02

ThreadID: 37450 Views:3180 Replies:8 FollowUps:2

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anglepole

After changing over my HF transceiver to a GU Patrol I was pleasantly how "electrically quiet" the motor was when running, no interference in radio.

However when the vehicle moves (ie speedo moves,) this causes RF interference in the HF Radio. When the vehicle comes to a halt interference disappears. Turning off the engine, and ignition on the noise still persists.

The speedo in this like most modern vehicles is a Hall Effect unit. The noise is constant and probably from a instrument regulator.

Has any one had this problem and knows a fix?

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Reply By: brian - Tuesday, Sep 05, 2006 at 14:43

Tuesday, Sep 05, 2006 at 14:43

i have barrett 950 in 2002 3litr it has no interferance due to the vehicle, only background noise which i am told by the installer is normal...absolutely no difference if motor is on or off or vehicle is moving,however i have several dirrerent earth leads...

AnswerID: 192941

Reply By: Member - Captain (WA) - Tuesday, Sep 05, 2006 at 14:47

Tuesday, Sep 05, 2006 at 14:47

Hi anglepole,

I have a Barrett 550 in my 3.0TD GU and like Brian have absolutely no electrical interference. I would check your earth wires, particularly the autotune earth and main unit earth, and see if this makes any difference.

Cheers

Captain

AnswerID: 192944

Reply By: joc45 - Tuesday, Sep 05, 2006 at 14:51

Tuesday, Sep 05, 2006 at 14:51

Unless Nissan have changed the design, I think that the speedo sensor is less hi-tech; I recall testing mine to prove it was simply electromagnetic. In any case, the 3.0L, the 4.2L and the 4.8L petrol would all share the same equipment. I have no noise when rolling in my 4.2 series I.
Some rubber compounds in tyres generate static noise. Is it continuous hash or has it a repetitious nature?
Have you fitted a cruise control? It's possible that the circuitry in that is generating noise when rolling. (tho my CC is noise free)
Gerry

AnswerID: 192945

Reply By: cam_champion - Tuesday, Sep 05, 2006 at 14:57

Tuesday, Sep 05, 2006 at 14:57

the GU patrols had a problem with their body earth that causes many strange electrical problems in some vehicles, a recomendation that I had to solve some of these was to run another earth strap from the battery or engine block to the body. try this and see if it helps your interference problem

AnswerID: 192947

Follow Up By: Member - JohnR (Vic)&Moses - Tuesday, Sep 05, 2006 at 15:14

Tuesday, Sep 05, 2006 at 15:14

cam, the the chassis from the engine block, body or the battery, would be better.

FollowupID: 450785

Follow Up By: Member - Roachie (SA) - Tuesday, Sep 05, 2006 at 15:18

Tuesday, Sep 05, 2006 at 15:18

Yep, it's the chassis which does not have good earthing. There is a captive nut (10mm thread I reckon) on the top side of the chassis rail, just near the turbo (ie: passenger's side, just aft of the front axle area). This is where I attached a reasonable sized cable to the negative terminal of my 2nd battery (when I had one under the bonnet). After I moved that battery to the cargo area, I re-attached the earth strap to the back of the alternator to ground the chassis properly.

FollowupID: 450786

Reply By: traveller2 - Tuesday, Sep 05, 2006 at 15:01

Tuesday, Sep 05, 2006 at 15:01

Another source of noise can be that the panels, doors etc are isolated electrically from the rest of the body.
Try putting an earth strap across the bonnet and door hinges.
Grounding the rear end of the exhaust can also help to remove static noise generated when the vehicle is moving through the air.

AnswerID: 192949

Reply By: Gmouse - Tuesday, Sep 05, 2006 at 17:02

Tuesday, Sep 05, 2006 at 17:02

do you have a ground strap from the antenna to the chassis?

Cheers

AnswerID: 192968

Reply By: Angler - Tuesday, Sep 05, 2006 at 21:35

Tuesday, Sep 05, 2006 at 21:35

My codan seems OK on the 2003 model. I do notice the car radio is noisier on AM from distant stations when travelling. I haven't tried any suppressors yet.

Pooley

AnswerID: 193037