For septic here, we have a Clearstream septic tank / UV purifier system. Unfortunately, that power supply for the underground UV light purifier spectrum-wide threw hash of over S9 from LF to to the 6M band. So, two .1uF 250VAC CAPīs, one on terminals of the UVīs AC input, and the other on the UVīs DC output. Now, you have to have a portableīs antenna right over that UV power supply to hear that hash. Panasonic appliances are also notorious for spectrum-wise spurs from DC to light. Heavy investment into ferrite chokes helps to a degree. Then, thereīs DSL MODEMīs. Ferrite chokes on every cabling going to and fro that unit. Then, thereīs CFLīs and LEDīs lighting cheap power supplies. Choke them, where ya can. Now, the AC BZZZZZZZZZZZZZZZZZZZZZZZ that comes from the band-aid fixes from the utility power lines? Move your antennas as far as possible away from that, since the power companies will not want to spent one cent of their quarterly bonuses to have to fix those. And I can hear that all the way into the 222MHz band. Grrrrrrrrrrrrrrrrrrrrr.....