i remember years ago that guys used to attach condensers to the generator or to the voltage regulator to suppress radio/ignition noise. a couple of years ago, i replaced my old alternator + voltage regulator with a two wire alternator with the internal voltage regulator. i have a lot of radio/ingition "noise". can i still attach a condensor to the alternator & where & how many ohms, or should i pursue an electronic suppression unit that would attach to the antenna cable radio plug ? tkx
For condensors (a/k/a capacitors) we measure the properties in farads. For this applicaton we use mico farads abbreviated as mf. For reasons beyond the scope of this discussion we use about 5 mf rated at 12 volts. There are basically two types of noise. I separate them into pops and whine. If it is a whine that varies with rpms then I assume the source is the alternator. If it is from a diode that has become noisy the addition of filters will have little effect. The alternator must have the rectifier bridge replaced or the unit must be changed. If it is popping progressive with rpm then I assume pugs wires first which may require getting a new set.
I agree. Reducing noise must be addressed at the source. Though it is possible to reduce noise through filtering, it is best to locate the source, and fix the problem. Question, is this a factory radio, or aftermarket unit. How is the unit grounded? Knowing what you have will assist me in the fix. Ray
ray: the radio is from a 79 camaro . works fine locally. it is am/fm 8 track. the noise occurs on weaker stations, especially the AM. the noise is like the plugs firing . it is not a whine. u will also hear it near power lines as the signal fades in & out. was the use of a condenser attached to the voltage regulator, like my voltage regulator that i removed, to help suppress ignition noise ? the radio is grounded by contact with the mounting nuts of the radio shafts to the bezel and the screws of the bezel to the dash. the bezel was fashioned by the previous owner so that he could use one of the 80's small faced radios. it is made of aluminum and looks like just like the regular plastic bezel. i cut a larger opening in the bezel to fit the radio into. cannot remember if the wiring harness into the back of the radio has a separate ground. have to check the din schematic. it could in effect have two paths to being grounded.
From your description, it sounds to me like a normal condition, not normally noted in most sound sysatems due to the use of tape or CD units. AM is very sensitive to noise due to its very design, which required a sensitivity to noise characteristics. Weak stations, or noise in blank areas of the dial were normal. There are some things to check, however, which may reduce or eliminate most of the problem. Carefully check the antenna, including the cable, and the grounding of the mast itself. While the mast should not be grounded, it should be properly mounted, and tight. It is also very possible that the cable has deteriorated over the years, making noise enter the cable input itself, adding to the problem. Also, be sure the radio chassis is properly grounded; add a ground if necessary, but be aware that two grounds may ADD to the noise if a ground loop is created. If nothing else, the reception may improve, which will allow lower volumes, and that in itself will reduce noise. If push comes to shove, there are procedures for locating the source of the noise, which is likely spark plug wires, from your description. You might try the use oof the magnetic suppression wires, which will reduce the resistance in the circuit. It uses inductive suppression. Let me know... Ray
ray: the antenna is our favourite in the windshield. the connections there were good when i checked them 2 years ago when i installed this radio. the plug wires are almost five years old & are ac-delco noise suppression wires and the plugs are ac-r44. i have a new antenna that i bought to test this radio on the bench so i will connect it to the radio, ground it and see what happens. i am not against buying new wires. i will try a few things first. to all u guys, i say tkx.
