inputs.text: signal 2 noise ratio throwback 1950s tube radios - plan take back bought experience worst signal noise ratio since 1950s tube radios xm signal weak weak weak hear spark plugs loud clear called xm support center new delhi found never heard ignition noise asked several times \\your channels not working sir\\ local radio shack helpful sold ground loop isolator adaptor 27 dashboard looked like 1950s telephone switchboard wires hanging sound not improve hookup method supplied aux cord aux receptical vehicle tried two vehicles 2009 chev silverado 2008 lexus 250 lexus spark plugs sounded bit muffled refined still overwhelmed xm signal not think hope onyx canceled xm service plan return