Don, and the group, This is not so complex. As you surmise, parts of the house wiring are being switched in and out by devices on it, and the broadcast RF present on the wiring is being modulated by that switching.
While probing around the house with an untuned RF detector, I've found power and thermostat wiring to be RF hot -- but using a meter with a detector in it (Credence Technology's "EM-Eye") I was able to confirm it was RF from several nearby AM radio stations and not generated by devices actually on the line. Several volts of RF may be present on home wiring. The "cure" is either to remove the RF from the wiring (easier to say than do) OR to isolate the switching devices from the power line at RF - and THAT is feasible. As to whether there are standards that apply to "modulation interference," the only one I can think of concerns flicker. The *FAA* has rules on what conducting structures may be built near a VOR (possibly other NAVAIDS, too) because of re-radiation, but I don't think they address errors due to intermittent connections from structures outside the clear zone. As an aside, I've suggested to other QRP enthusiasts that one could operate at *zero* RF power by switching a sufficiently large antenna to modulate another station's signal. One early "radio" system did use such modulation of the natural electric field for wireless telegraphy over a distance of some miles. Cortland ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
