[RFI] Device Generating RFI Fix
wd8arz at ix.netcom.com
Mon Aug 7 08:34:41 EDT 2017
Many of today's electronics use AC Switching power supplies. That method
avoids the use of transformers saving on cost, weight and size of the
device. Instead 'switching' power supplies circuits are used. That
method of chopping the a power source to achieve the voltage and current
from the device as needed to run that equipment, does generate a lot of
spurious signals. Some of them are radiated as radio frequency energy
(RF). A lot of interference can be generated by such devices and be
received by other devices, especially when other devices are close to a
radiating piece of equipment.
Unfortunately, many such power supplies do not use a true on / off
switch that mechanically disconnects the power supply from the a.c.
mains. Thus turning the device "off" may not in fact remove power from
the switching power supply. It is left running to support the 'instant
on' feature. To remove the interference from such a device requires
pulling the power cord out of the ac outlet to truly turn it off.
So when looking for a radiating interfering signal, pull the power cord
to truly test if that device is the problem or not. Good luck on such a
quest of find that type of interference .... 73 from Bill - WD8ARZ
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