For example a family member installed a legally sold 'electronic
thermostat' to better control the heat in their bedroom. It did a good
job of that. But ...........
Unfortunately it emitted RFI (Radio frequency interference) that
interfered with the bedside radio in another room; even when it was
tuned to a local radio station!
We have since removed it and relegated that thermostat to another
person's garage where it does not (so far) cause interference! But one
does wish the regulatory authorities such at he FCC in the USA and the
Canadian Dept. of Transport etc. would not permit the sale of these
interfering devices which include certain light dimmers etc.
It appears that just because something is UL (Underwriters Labs.) or
CSA (Can. Standards Assoc.) approved and is therefore 'safe' it may
not be free from causing interference! Also some incompatibilities
occur. Yesterday visited the lamp/light fixture show room of an
elecrical supplier and during discussion the topic of NOT using
dimmers with CFLs came up. Apparently some of their customers are
still not aware of that!
Exactly; and the show room staff mentioned that those dimmable CFLs
are very expensive!
LEDs 'may' be the way to go. But since we are electrically heated and
most months of the year, here, require some warmth, especially at
night, so incandescent bulbs work fine for the present anyway.
In fact we have a bathroom, with six 40 watt incandescents (240 watts)
above the vanity that are only on occasionally (when room is occupied)
and the electric baseboard heater only comes on in coldest weather. It
appears that we replace a only a couple of 25 cents incandescent bulbs
in that bathroom per year.
I've returned a lot of those; I can't tell the difference between them
and a regular CFL (e.g. none of them really work as advertised.)
I bought two dimmer friendly CFL lights from H.D. They work as advertised.
They have larger bases from the regular Cfls.
The FCC DOES regulate such devices. All electronic devices are required, by
law, to not interfere with electronic communication. The fault, however, may
lie with your bedside radio in that it does not conform to universally
accepted filtering circuitry. If the thermostat was made by, say, Honeywell
and the radio was made by, say, Hung-Lo industries, I'd say junk the radio.
It is more likely the radio is ok and the Thermostat is generating the
interference. Probably any radio in the same location would pick up what is
being generated by the thermostat. There should not be anything in the
thermostat to generate a signal strong enough to cause problems with any
Interference did not start until the thermostat was installed.
The interference was definitely being generated by the 'electronic'
thermostat as it chopped the waveform and cut in and out on a regular
basis. The second replacement thermostat does not cause interference.
And yes another battery operated radio does also pick it up.
In regard to other matters of interference it can be deficiency in the
gear itself (early TV sets were notoriously unable to reject some
signals that today would be considered quite normal). Also can be a
matter of being in such close proximity to a powerful transmitter
(including a 1000 watt microwave oven!) that the signal just 'swamps'
or 'blocks' by overloading input of the other device.
Often, the interference is coming across the power line as much as
through the air. At night, going to sleep, I like to listen to far-away
radio stations on an itty-bitty multiband radio powered by a wall wart.
(my version of cheap travel.) One of my neighbors on same transformer
can has something that once in a while, puts out so much static, that I
can't get squat on any station. Same problem on multiple wall warts and
multiple radios ( I have several). I know it isn't my house, because I
have tried turning everything I have off, and unplugging wall wart makes
most of the static go away. The closer I hold the plug to the radio, the
louder it gets. I've looked out the windows- it isn't anything obvious
like a yard light. I think it is a bathroom/kitchen appliance of some
sort, because it often starts up again at around 0600 or shortly before,
and wakes me up.
Cordless telephone interfering with Wi-Fi connection when in close
proximity to computer. It will swamp the desired signal.
Cell phone to close to bluetooth mouse. It will also swamp the desired
Many low powered devices operate on the same frequencies. They operate
under what is often called Part 15 of the FCC rules. If you look at the
fine print on them, you will see something like they must accept
interference from other services, but can not cause problems.
That means all the Part 15 devices such as the cordless telephone and Wi-Fi
can interfere with each other and that is ok. They just can not interfere
with any licensed devices and must accept interference from them.
Chuckle. People in my office always bitch when I key up my ancient
Motorola ht1000 at my desk. Makes a nice loud hum in their speakers.
Back when they still let me touch hardware, I was once tearing my hair
out on a monitor service call- funny colors, wavy lines, etc.
Replacement monitor did the same thing. I was about to swap out the CPU
(integrated video on those early machines), when my 2 active brain cells
kicked in, and I noticed the electric stapler tucked up against the
monitor. Those are a first cousins to doorbell dinger- bigass coil and
magnetic rod inside them. Moved it two feet away, and the problem vanished.
A few homes ago my monitor was back to back with the microwave (with a
wall in between). Every time the microwave operated it looked like I
was degaussing the monitor. Sometimes I'd have to tell my daughter to
turn off the microwave until I finished what I was doing.
You probably were. When the transformer was active it was generating a
magnetic field just as a degausing coil would. I have never tried it,but a
LCD type of display probably would not have been effected by the microwave.
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