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Take a long wire antenna. Ground the far end. Notice the
grounding does not eliminate signals. And yet is AC electric faults to that antenna wire, then it is a complete short circuit. Wire is not a perfect conductor. Therefore with frequency (and other electrical) differences, then how wire is affected by ground varies completely. A tall steel and concrete building is completely one big grid of earth grounds. That is why long wave and near low microwave signals don't propagate well. However, that same network of steel girders earthed at the bottom can still be a good radio antenna for some frequencies. Noise is quite complex. For example noise from appliances can propagate through the air OR it can be carried by utility wires. Some noise on AC electric only exists when the receiver 'measures' a voltage difference between any/all incoming AC wires and earth. This last type of noise is called longitudinal noise. Just another reason why sometimes the best solution to noise is either a stronger signal or solutions applied to the noise creating appliance. There is no simple ground and there is no simple solution to noise which might explain why so many EMI/EMC engineers are bald. An excellent earth ground is obtained by connecting to the steel girders. Wall receptacle ground is (typically) not earth ground. The two grounds are connected by a wire. How well connected can be determined by length, routing, and what that wire passes through. The window may or may not be a connection to building earthing depending on how that window attaches to the steel building frame. If connected, then the window is but another way to use the building steel girders as a big antenna. To better understand it all, first learn the wavelength of that frequency. Frequency in hz times wavelength in meters is 3.0E8 (meters per second). Welcome to an art: grounding. Lucky wrote: I was trying to do the right thing according to manuals and some articles I read, plus lower the noise floor. I always thought this unwanted "noise, static, clicks, lightning and other garbage" needed somewhere to go. That you wanted to provide a path for it so it didn't find it's way to the radios speaker and then your ears. I bascially do BCB during the day, some Hams, shortwave programs during the early night and Hams again later at night. I live in Florida and like listening to the Southern Hams late at night. Some stay on very late. I'm bascially talk programs during the day and all over the night frequencies at night. Whatever catches my interest. I even listen to the Liberty net every so often for fun. Thanks Lucky |
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