Great Noise Guy


Active Member
RFI Services

6469 Old Solomons Island Rd. Tracy's Landing, MD 20779
Phone 240-508-3760 FAX 410-257-4514 Email us here for more information

"How to" locate tips

" How to" Locate Radio Frequency Interference (RFI) or Television Interference (TVI) in a Home

All steps should be performed while interference is active
1. Go to your main circuit breaker or fuse panel with a battery powered AM radio tuned between stations so all you hear is the offending noise. ( If at night or in an enclosed room, be sure to have a working flashlight. )

2. If the noise is present and corresponds to the disturbing interference, shut off all power to your premises by turning off the MAIN circuit breaker or equivalent enclosed device. (DO NOT ATTEMPT TO REMOVE CARTRIDGE FUSES or OPERATE EXPOSED or OPEN-TYPE DISCONNECTS IF PHYSICAL CONTACT WITH ELECTRICAL CIRCUITS IS AT ALL POSSIBLE.) If the noise on the AM radio stops while the power is off, the source of the interference is within your own residence.

3. Restore the main circuit breaker. Don't forget to reset clocks after the interference source is located.

4. Assuming the noise stopped while the electric was off, you can now locate the circuit supplying the power to the noise source. While monitoring the battery powered AM radio as before with the offending noise present, turn off and on the individual circuit breakers one at a time until the noise stops. Leave off the breaker that stops the noise.

5. You must now determine what has been turned off by going from room to room, if necessary, checking outlets, appliances, and lights for the absence of electricity. The offending noise will be something on this circuit. Turn the breaker back on and wait for the noise to return.

6. With the noise back on and using the AM radio to monitor it, return to the area of the noisy circuit and unplug everything on this circuit one at a time until the offending device is found.

Things most commonly found to cause interference are:

Door Bell Transformers Electric Blankets
Heating Pads (of all kinds) Recessed Ceiling Light Fixtures
Furnace Control Circuits
TV Top & Stereo, Amplified Antennas (*) Causes Radio Interference Only
Aquarium Heaters *Screw In Photocells
Low Energy Compact (screw in) Florescent Lights *Touch Control Lamps
Clean Air Machines (table top and furnace type) *Light Dimmer Controls

These devices, when causing interference, are in violation of Federal Communications Commission rules, regulations and are a nuisance to you and your neighbors. It is important for your own safety to have the offending device repaired or replaced to insure normal safe operation. Most radio and television interference sources are the result of an arc. This arcing will get hot and create a fire hazard. Your interest and assistance is sincerely appreciated. For more information about RFI & TVI contact:

RFI Services’ Interference Investigator, Michael C. Martin

Tel 240-508-3760 Fax 410-257-4514 Email us here for more information.

Please include with all inquiries: Name, Company, Phone, Fax, E Mail and Address


I had a great conversation explaining how RF can make its way into the powerline of a home treating it like an antennae.

He did not believe in filtration. This makes things a bit more difficult to convince some that equipment may just need to be replaced if interfering.

Did this help any of you with your issues..Me neither but I know more than I did.
Heh. Great post.

When my "Invisible Fence" for dogs stops working, I can find the break by tuning low on the AM band on a portable and listening for the transmiter noise to stop. Kind of the flip side :unsure: