UHF Radio Interference

The cheapest and most effective option is to run 4mm cable from to battery to the radio for both 12 volt and earth leads. The battery is the best filter against noises generated by vehicle electrical systems.

maybe a silly reply, but did you connect your aerial and more importantly did you do it correctly. i connected mine how i thought was correct but later found out through some problems that i didnt do it right. repair costs from the repairer was $10 . so maybe get it checked out. good luck.

Phiem.
Sounds like the radio is not earthed solidly to the body, the best earth is the shortest wire posible the thichness of the wire is not critical. the inbiult filter on the positive input should be able to handle the vehicle noise if it is earthed properly. Check the outer of the coax is soldered at both ends.
Eric.

Try these links for good information on mounting, tuning & problems

http://www.mobileone.com.au/tune.htm

http://www.gme.net.au/land/choose_ant.html

http://www.alphalink.com.au/~parkerp/cb.htm

Rob

Philem what is in your view a "ground independent RFI aerial"? an other marketing term to sell the antenna at a higher price. Your hum comes from a capacitance problem between your aerial and the "ground"/chassis of the vehicle. As it has been said previously some parts of your vehicle are NOT ALL grounded together. One of the main problem is the petrol tank usually being insulated. Ground all your UHF cable. ( I mean the external part of it, NOT the centre core). Guy