A M Radio Interference-need fix??
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Junior User
Joined: Nov 2005
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A M Radio Interference-need fix??
2003 f150 has alot of raspy am radio interference that increases with rpm. There is no interference when the key is in the Acc. position. This has done it since new but is getting a little worse. I have seen on other sites that say this is common to alot of late model 150s but have not seen what the fix is. I tried another radio out of my ford ranger that didnt have that problem but it did it in the 150. anybody have experience with this late model problem or a fix for it?? (I do want to keep using AM) Thanks
Last edited by fire105; Nov 30, 2005 at 11:55 AM. Reason: spelling
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Junior User
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Thanks, I will try that----according some toubling shooting charts I have seen, a raspy static sound like I have is related to the ignition, and a whine sound is relatied to the alternater. If the alternator ground wire doesnst work than I dont know what could be changed in the ignition?? thanks
Hotshot
Joined: Jan 2004
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From: St Louis
Alternator noise on the AM band is often cause by an improperly grounded antenna.
The base of the antenna mount (not the center conductor) must make excellent electrical contact to the steel body of the vehicle. Paint, sealant, rust, or dirt often keeps a good electrical contact from occurring.
On my old 93 Exploder, I had to remove and clean the mounting surface every year to keep good quality AM reception.
When the electrical ground (at RF frequencies) degrades, the steel body no longer acts as an antenna ground plane and allows the RF energy from the vehicle electrical system, particularly the alternator, to be induced into the antenna.
Steve
The base of the antenna mount (not the center conductor) must make excellent electrical contact to the steel body of the vehicle. Paint, sealant, rust, or dirt often keeps a good electrical contact from occurring.
On my old 93 Exploder, I had to remove and clean the mounting surface every year to keep good quality AM reception.
When the electrical ground (at RF frequencies) degrades, the steel body no longer acts as an antenna ground plane and allows the RF energy from the vehicle electrical system, particularly the alternator, to be induced into the antenna.
Steve
Last edited by projectSHO89; Dec 3, 2005 at 09:35 AM.
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Verify that AM reception is good with the engine off, but the key is in the ACC position (with the key in the OFF position, turn it one notch in the opposite direction from usual). If AM is still bad, the antenna lead may have some corrosion at the point that it plugs into the back of the radio. This was a problem that I had with my 1999 Expy.
