UHF Radio Interference

Graeme, I'd be looking at poor electrical connections being vibrated by the vehicle motion.

1. Most likely. The antenna cable and its connections to the radio and to the antenna.
2. The antenna itself.
3. Vehicle panels and in particular the tray. You could try a temporary earth by using battery jumper leads. Connect one black clamp to the battery negative and the other black clamp to the tray then drive the vehicle.
4. Does the interference occur if the vehicle is stationary but with the motor revved a little as if driving? If so it could be an alternator problem.

Can you describe the static ?

- a whine that changes in pitch
- a crackling
- a buzz

Is the actual radio mounted on a plastic part of the vehicle?
If so run a ground/earth wire to the body of the radio, some require the actual body of the radio to be grounded in addition to the normal power and antenna connections.

OK, I have a 3.0 ltre Patrol. I had (have) the same problem with my HF radio and tracked down the problem to the Speedo Electrics. When the vehicle reaches 5km/hour the noise starts. The interference comes from one of the computer modules.

I proved this by carefully and safely jacking up the rear of the vehicle and simulated about 10k and turned of the motor the noise disappeared.

Another trick is to run your radio off a separate battery (8 dry cells will do) and see if the interference stops: if it does, the interference is from the input voltage, if not it is coming in via the antenna.

Good luck