Radio Noise
Hi Folks.
Most Noise comes from poor circuit components, and it's termed as stray RF, it can be fixed in lot of cases, but you need to determine what's the cause.
you can get from Jaycar a noise supressor and it goes in line on the radio coax it filters out some of the interference caused by cheap or poor designed circuits.
But any electrical circuit does create some electrical noise! fluorescent lights are a good one, Cheap LED down lights, your LED TV's and to a lesser extent plasma's.
But in a car simple start points.
1) move the coax far from any live wires
2) use better quality coax (Better shielding) make sure you have the correct coax being used (50 ohm)
3) make the coax run as short as possible (better in lengths of QTR wave)
4) any additional coax form a simple coil about 6-7 turns ( acts as a RF trap)
8) ensure the antenna is well grounded (earthed) run a second earth to the antenna base, don't rely on the Bullbar mount bolts as an earth point
9) Move the antenna away from the lights if possible.
10) make sure the radio is earthed THE NEGATIVE WIRE (black wire) although is run to earth doesn't mean the radio is, on most radio's there is a small earth screw on the back run a lead from this to an earth point car chassis or panel.
If this don't work then you start investigating the equipment causing the issue,
Simple fixes here are
Static charge build up fixed by earthing better (once again circuit earth may not be the same as equipment earth.
Live wire filters or suppressors
Use shielded Live wires to the equipment
check to see if the live feed wire is good enough for the current draw
Does the equipment comply to Std's
Hope these couple of points help in locating some problems.
Pat S