Quick and easy way to find out how much difference a power-line filter will make to your problem.
UNPLUG THE ANTENNA!
Naturally you should make sure the squelch is open, the ANL/NB are both turned off, and the volume is at a normal listening level.
If you hear any noise this way, without any antenna at all connected, that noise may be entering the radio through the power connection. And whatever noise you hear this way is what that power-line filter will fix.
If you hear no noise at all this way, that's exactly how much the power-line filter will fix.
And if ALL the noises go away until the antenna is reconnected, that means that your noise sources are transmitting those noises into the air. Your antenna will pick them up.Just the same as it picks up the signals you want to hear.
Way too many noises caused by devices in your vehicle must be suppressed at the source, before that noise energy feeds into the vehicle's wiring harness. I have seen a few cases where putting the antenna too close to the tail light made the noise level higher. The wiring harness in your car is a transmitting antenna. Anything in the car that feeds noise energy into it gets transmitted into the surrounding area.
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