Radio Frequency Interference (RFI) fix needed

[Sailing Santa]

I can commiserate. After all the research and poking around with an o’scope, I can concur that the majority of the RF noise is directly caused by the unshielded injectors firing and slapping back. If you look under the cover, you will see each injector being controlled by a pair of wires - not shielded or even twisted. So, my first attempt will be to twist the pairs, sneak the pigtails through some braid harvested from coax and finally a snap-on ferrite choke : per injector. I’m a little afraid to add a clamping diode into the circuit.

 

[Sandevino]

Did you ever eliminate the problem? I’ve got the same issue in my 2023 1500 w/ 5.7 eTorque. I’ve got the IC-7100 mounted in the center console, Tarheel Designs Little Pro mounted in the front passenger stake pocket on a Breedlove mount. I’ve got ferrite chokes, shielded coax, moved the antenna around several times, bonded everything with 1” copper strap and still have the issue. I predominantly hear ignition noise / static on 20m and other oddities on 40 and 80.

I tweaked the noise blanker and was able to stifle the majority of the interference but am looking to eliminate the source of the problem.

 

[Njdan30]

I'm also battling a lot of popping static noise on my 2020 warlock 5.7 on am it's tolerable but side band lower or upper it's horrible. I too thought it was the drive by wire as the second I touch the pedal it happens, if I let up and cruise it'll go down, also noticed on really cold days it's not as bad,I recently bought another new radio in hopes of would be a little better but it's actually worse (galaxie dx94hp) new radio is a stryker 955. I'm taking my ham operator test this month but I'm mostly on the 11 meter bands but mine to listen to other bands me I said am and fm are on but ssb is terrible. I too. Tried everything the op tried with grounding, wiring etc. Any help would be greatly appreciated

 

[RamDiver]

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[RamDiver]

Did you ever eliminate the problem? I’ve got the same issue in my 2023 1500 w/ 5.7 eTorque. I’ve got the IC-7100 mounted in the center console, Tarheel Designs Little Pro mounted in the front passenger stake pocket on a Breedlove mount. I’ve got ferrite chokes, shielded coax, moved the antenna around several times, bonded everything with 1” copper strap and still have the issue. I predominantly hear ignition noise / static on 20m and other oddities on 40 and 80.

I tweaked the noise blanker and was able to stifle the majority of the interference but am looking to eliminate the source of the problem.

Do you have access to an oscilloscope?

I would examine the power feeding your radio with an oscilloscope to prove it's clean.
You could try using a multimeter on the AC mV setting but a scope will tell all.

Sometimes the ignition noise can be severe enough that standard chokes are insufficient.
Anything more than a few millivolts into your radio could be the source of your grief.

I recall having this problem with CB radio in the 70s with certain vehicles.

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[delf]

I have a 2011 RAM 1500, 5.7L. I have HF ham equipment that suffers RFI from the ignition system. The interference is NOT coming in via power wiring as the interference completely disappears when the antenna is disconnected and a portable unit also picks up the noise when near the truck. There is one interesting bit of behavior I discovered on a long trip. On a long steep downward grade of interstate, if I let the truck coast, not in neutral but in Drive, the interference completely disappears. Not just a little bit but completely gone. When the grade starts to level out and the truck speed starts to slow, the ignition noise resumes. If while coasting down a grade I add a little gas to increase the speed (already coasting consistently at around 70) the noise returns until I let off the gas and resumes a consistent coasting speed.

My thinking is that it's the fuel injector circuitry causing the interference, and probably not the coil packs/spark plugs. Does anyone know if the engine management computer shuts off just the fuel injectors when coasting in this manner or are the coil packs also put on standby? Not that it makes any difference over all, I'm just curious if just the injectors are shut off.

My last resort solution, if ferrite cores on the wiring harness are not effective, is to wrap the entire ignition/injector harness with copper adhesive tape, grounded at multiple points. I'm just not enthusiastic about pulling out the harness to do this and it doesn't look like an effective job can be done trying to wrap with the harness left in place.

 

[RamDiver]

I have a 2011 RAM 1500, 5.7L. I have HF ham equipment that suffers RFI from the ignition system. The interference is NOT coming in via power wiring as the interference completely disappears when the antenna is disconnected and a portable unit also picks up the noise when near the truck. There is one interesting bit of behavior I discovered on a long trip. On a long steep downward grade of interstate, if I let the truck coast, not in neutral but in Drive, the interference completely disappears. Not just a little bit but completely gone. When the grade starts to level out and the truck speed starts to slow, the ignition noise resumes. If while coasting down a grade I add a little gas to increase the speed (already coasting consistently at around 70) the noise returns until I let off the gas and resumes a consistent coasting speed.

Back in the day, when I was chasing RFI, the largest contributors were spark plugs and the rectifier attached to the alternator.

Do you experience this RFI during idle?
Could you sit in the truck while stationary and identify the relative RPM where the RFI begins?

My last resort solution, if ferrite cores on the wiring harness are not effective, is to wrap the entire ignition/injector harness with copper adhesive tape, grounded at multiple points. I'm just not enthusiastic about pulling out the harness to do this and it doesn't look like an effective job can be done trying to wrap with the harness left in place.

If you have isolated the ingress point to be related to the antenna, why would you spend time shielding the harness?

What type of antenna and how is the ground plane created?
Could you post a picture of the antenna or provide a link and identify how/where it's mounted?

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