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Noise control for AM radio?
- Thread starter 58Custom
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58Custom
Jedi Warrior
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OK, basic stuff. I was wondering if there was anything special the factory did. The solid core wires do not help with the noise.
I have an AM/FM radio in there now, but reception for all radio sucks once you get north of LA because of all of the mountains. So I have to deal with marginal and intermittant signals. Sometimes I needs the traffic reports.
I have an AM/FM radio in there now, but reception for all radio sucks once you get north of LA because of all of the mountains. So I have to deal with marginal and intermittant signals. Sometimes I needs the traffic reports.
regularman
Yoda
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get a good sized capacitor and hook one side to the + on the radio, right near the radio and hook the other side to ground.
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The standard fix is to use resistor wires for the plugs. This really isn't practical in spridgets, though, and may not work with conventional ignition. You can get resistor versions of the conventional plugs, which may help. If you have an electronic ignition system, resistor plugs are probably OK, but I wouldn't use any resistive secondary wire or plugs with conventional ignition--it's just not designed for it. Some kinds of original L-shaped plug connectors also have resistors in them, but they are only a few ohms and I can't see this doing any good.
If you have conventional ignition, connect a large capacitor from the + terminal of the coil (i.e., NOT the terminal that goes to the distributor) to the chassis. I'd use something like 10 microfarads, at least 400 volt rating. (Greater numbers are OK.) This will be a so-called electolytic capacitor. Be sure to observe the capacitor's polarity. The positive terminal goes to the coil, assuming you have negative ground. Otherwise, the negative side goes to the coil. Don't do this if you have an electronic ignition; it will probably mess up its operation.
Definitely, put a large capacitor from the 12V terminal of the radio to the chassis ground. This needs to have only a 20V rating or greater. I'd use, again, at least 10 microfarads here, but more is OK, maybe better. Again, observe polarity of the capacitor.
After all this, there still may be interference that comes in through the antenna. Locating the antenna as far as possible from the engine may help a bit, but there really isn't much you can do for this. It will be worse on AM, probably won't occur on FM but it might, a little.
If you have conventional ignition, connect a large capacitor from the + terminal of the coil (i.e., NOT the terminal that goes to the distributor) to the chassis. I'd use something like 10 microfarads, at least 400 volt rating. (Greater numbers are OK.) This will be a so-called electolytic capacitor. Be sure to observe the capacitor's polarity. The positive terminal goes to the coil, assuming you have negative ground. Otherwise, the negative side goes to the coil. Don't do this if you have an electronic ignition; it will probably mess up its operation.
Definitely, put a large capacitor from the 12V terminal of the radio to the chassis ground. This needs to have only a 20V rating or greater. I'd use, again, at least 10 microfarads here, but more is OK, maybe better. Again, observe polarity of the capacitor.
After all this, there still may be interference that comes in through the antenna. Locating the antenna as far as possible from the engine may help a bit, but there really isn't much you can do for this. It will be worse on AM, probably won't occur on FM but it might, a little.