Extreme RF Gremlins - Can anyone assist?

[JayMojave]

As we have seen many times here on this forum, Yeah what prcguy says. The pulse type noise from the ignition system is radiating RF noise. It all needs to be replaced, that is spark plugs, wires, Rotor Cap, and the rotating contact in the distributor. This would be a good start.

RFI ( Radio Interference ) has three things to be concerned with, they are:
A source of the RFI = The ignition system
A path to the receiver = RF noise being transmitted into the air
A Receiver = The CB Radio

Its always best to fix the RFI noise at its source. But at times if the path or receiver can modified to significantly reduce the RFI we will take it.

The Path may be reduced by connecting the fenders to the firewall to the Hood, using a brad type wire, like shield from coax. It worked for me.

The Receiver needs to have a good Noise Blanker or NB all ready designed into the radio, these noise blankers work pretty well. The ANL is a automatic noise limiter, but don't seem to work as well as the noise blankers NB do.

RFI interference problems are not the simplest to trouble shoot and fix. These RFI problems are everywhere, in anything that has electronics. Cars, Trucks, Aircraft, Boats, ships, home computers, and such all have RFI problems at times. The more electronics the more RFI problems.

Look at: Antennas Radios Amplifiers Baluns and Receiving Systems for HF
He has a article written on vehicle noise, and its all over the internet also with good inputs. Good luck, please let us know what you find out the fix is.

Jay in the Great Mojave Desert..... "Next Gas 150 Miles"

 

[prcguy]

The key to this particular case is the stock AM radio is getting the same interference as the CB. When the truck left the factory and then the dealer it had no noise in the stock AM receiver, otherwise the first owner would have returned the truck within hours of purchase.

Something has changed since the truck was new. Ignition components wear out and they can cause or increase noise. The truck was bought used so there is no way to know if previous owners changed out the plugs and wiring with aftermarket components. They could have even put in a high performance ignition system which is nearly impossible to tame the noise they make. You will know when the noise has been reduced to stock new truck levels by hearing no interference in the AM radio. Even with that a CB can still pick up some spark plug/ignition noise as they operate at a different frequency and are more sensitive than a stock AM radio.

As we have seen many times here on this forum, Yeah what prcguy says. The pulse type noise from the ignition system is radiating RF noise. It all needs to be replaced, that is spark plugs, wires, Rotor Cap, and the rotating contact in the distributor. This would be a good start.

RFI ( Radio Interference ) has three things to be concerned with, they are:
A source of the RFI = The ignition system
A path to the receiver = RF noise being transmitted into the air
A Receiver = The CB Radio

Its always best to fix the RFI noise at its source. But at times if the path or receiver can modified to significantly reduce the RFI we will take it.

The Path may be reduced by connecting the fenders to the firewall to the Hood, using a brad type wire, like shield from coax. It worked for me.

The Receiver needs to have a good Noise Blanker or NB all ready designed into the radio, these noise blankers work pretty well. The ANL is a automatic noise limiter, but don't seem to work as well as the noise blankers NB do.

RFI interference problems are not the simplest to trouble shoot and fix. These RFI problems are everywhere, in anything that has electronics. Cars, Trucks, Aircraft, Boats, ships, home computers, and such all have RFI problems at times. The more electronics the more RFI problems.

Look at: Antennas Radios Amplifiers Baluns and Receiving Systems for HF
He has a article written on vehicle noise, and its all over the internet also with good inputs. Good luck, please let us know what you find out the fix is.

Jay in the Great Mojave Desert..... "Next Gas 150 Miles"

 

[JayMojave]

Hello prcguy: I agree with you all the way they should be paying you for the experienced help here.

Working with heavy machinery farming vehicles, I was asked to help with a RFI problem of interference with the AM/FM CD radio/player that was the worst thing I ever heard. Senior EMI/RFI engineers and Spectrum Analyzers and RF Sniffer type stuff was brought in. WOW a small army of engineers and technicians to fix a problem that a new modification was causing severe RFI in the radio that was unacceptable for a production run and modification of the vehicle.

The result was a few digital sensors were changed out, shielded wiring was installed in some places, new ground system was installed, and the 50 dollar radio was replaced.

Point of all this Hoo Raw is that it looked like the three stooges running around in circules, but we finally got organized and started making progress a little bit at a time. Every RFI problem we came across was not the total fix, only a slight reduction in RFI interference as offending RFI parts and installation was fixed. This drove us nutzoid. Even with all these experienced people the trouble shooting, isolating. and repair was a significant difficultly even for the experts. So when a inexperienced person is trying to fix a RFI problem it will send them out of the shop wanting a break to catch their thoughts and such. RFI problems can be very difficult, I am sure you have run into this.

So one is forced to change things at some cost to fix the RFI problem, that's just how it is. And some times it doesn't fix anything.

But replacing the ignition system components to the stock configuration has to be the best call to start with.

Jay in the Great Mojave Desert.... "Next Gas 150 Miles"

 

[ForestRunner98]

OP have you resolved this issue??