Home gadgets that cause interference with other domestic gear. Bah ....

Feb 12, 2010 27 Replies

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!


You have to use a cfl that is specifically rated for use on a dimmer.

de quoted text - . 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.

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.

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.)

nate

I've got on of those EdenPure electric heaters with a remote control. When I am using the remote for my DVD player, it turns the heater on and off and even will switch it from High to variable.

David

Two more:

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 signal.

In an office once there was a Motorola walk-talkie radio and charger that sat right next to an old x86 computer. Seems that was killing the hard drive of the PC?? Never really found out for certain, though.

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 receiver.

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.

Pretty much any cell phone and any computer that I've used - if my cell phone is about to ring, I'll hear a "sputtering" through my computer speakers. Even laptops with built in speakers.

nate

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.)

nate

I bought two dimmer friendly CFL lights from H.D. They work as advertised. They have larger bases from the regular Cfls.

Hmmm, I am an active ham with full previledges, only thing causing interference with Wi Fi in my house is microwave oven in the kitchen. Dimmers, GDO, wireless thermostat, cell phone cordless phone, various HAM rx/tx are all fine. No problem.

Once I had to work on a problem caused by air port radar. Nearby large commercial computer system installation was going crazy at certain interval that was when the rotating radar antenna was pointed at the site.

I had a 92' Plymouth mini-van and read reports of that years crop of Chrysler engines has a bad habit of stalling if they drove close to some airports at the time the radar beam was pointed in their direction. Apparently the radar beam would shut down the electronic ignition.

We are currently experiencing a problem with a Sony cordless phone (Sony no longer makes cordless phones). This phone will shut down our in-house WIFI network whenever one of the phones is in use. We are looking for a suitable replacement that does not confect with our Nortel wired phones the way a Siemens cordless phone did. We returned it.

Hi, Likewise when they first used ABS on cars. The system used to go crazy if they drive it thru a long steel bridge.

Your vibrator will cause problems with your computer.

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.

terry wrote: (snip)

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.

-- aem sends...

They don't have to be the same frequency to swamp the front end of a receiver.

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