Ford F250 radio interference

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bcrosspac

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May 6, 2003
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I have a 2008 Ford F250 Turbo Diesel. My EMS system uses 462.95 without receive PL tone. My truck is emitting a signal on that exact frequency that causes interference with my EMS 2-way radio and my scanner on that frequency only. Any help with that issue? It makes it impossible to monitor that frequency. Thanks......
 

CCHLLM

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I have an '06 F350 diesel, so I can understand what you're dealing with, but we need more details. What power source are you using and are you using completely separate wiring for each radio? How are the radios grounded? How and where are the power wiring and antenna cables run? What kind of antenna mounting are you using? In body, brackets, etc? All of these things affect whether or not interference sources can affect the performance of the installation.

I'm gonna assume that this condition only exists with the switch on whether the engine is running or not. If not, tell us when the problem occurs. If it happens with the switch on but engine off, the problem is more generic and involves the processor portion of the computer systems. If it only happens with the engine running, then it's in the engine management I/O portions of the system. Either way, with both radios being interfered with, odds are pretty good that it's a radiated signal. If the noise disappears when you disconnect the antennas, that confirms the source is radiated. As you probably already know, PL will silence the audio but won't eliminate the fact that the receiver is being interfered with.

Somewhere the trucks electronics (and there are several black boxes on these trucks) are radiating a signal through the wiring harness. If your power and or antenna feedlines are run parallel with and strapped to any of the truck wiring harness, you're increasing the possibility of induced interference several fold. Ideally, your power and antenna wiring should never run parallel with the factory signal and power wiring, but that's pretty hard to achieve.

If you can find the section of the wiring harness that is acting as an antenna for the electronics, you can do some things to attenuate or reduce the interference. Remember, the signal on one wire may be induced onto several parallel wires in the harnesses, so don't be fooled by not being able to immediately find the source.

With switch on, engine off, turn the volume up on the radio so you can hear the audio outside the truck. Open the hood and run your hand along and around all the wiring you can reach. If it attenuates or enhances the interference, you're in the ballpark. Sometimes simply relocating the antenna feed lines works, sometimes minor repositioning of the factory wiring works, but most of the time the cure requires both getting the power wiring and antenna cables away from the factory wiring and running them at an angle to the factory wiring.

There's more to this than what's in my post, but this ought to get you started toward finding where the problem is located.
 
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