Just finished installing a 706 in a new Ford p/u.Diesel,ant is mounted in the bed behind the cab.I didn,t have noise through the power line,so it comming thru the antenna.It sounds like spark-plug noise..Really,noise speeds up as the speed does.It is a popping like sound,agn sounds like plug noise..But,this is diesel..Any one else have this problem in the Fords.73,john