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	RADIO FREQUENCY INTERFERENCE If you hear a radio station on your phone, the information on this page could be helpful

WHAT IS IT?
Radio Frequency Interference (RFI) is the reception of a radio or TV signal on a device not normally expected to do so. Almost any consumer electronic device can experience RFI, such as a telephone, CD player or VCR. Under special circumstances, even your water heater or dishwasher could display symptoms of RFI. There are thousands of radio frequencies in use around you all of the time. Usually they go unnoticed, but under the right situations, one or more of these frequencies will be received in an unusual way.

WHAT CAUSES RFI?
Radio transmitters generate RF by their very nature. This is the basic principal of how broadcasting works. Radio towers emit electro-magnetic energy. The electro-magnetic field affects your radio’s antenna, and the circuitry in the radio demodulates and amplifies that signal so you can hear it. However, you don't need a typical radio to receive a radio signal. Any wire can act as an antenna, and if you are close enough to a radio tower, reception is possible without much else. Click Here to read more about how radio frequencies are transmitted and received.

RFI is not necessarily an indication that there is something wrong with the station's transmitter. The Federal Communications Commission (FCC) regulates all radio stations in the US. The FCC authorizes each radio station's frequency and power, and stations are required to monitor and maintain strict technical standards of operation. The FCC can fine a station or revoke their license if they are not operating within legal limits. Therefore it is extremely rare for a station to be out of tolerance enough to cause illegal interference. Usually, something within the system experiencing the RFI is at fault.

WHAT CAN THE RADIO STATION DO TO HELP ME?
There isn't much we can do to help you, other than make sure our equipment is functioning properly. To ensure that we are operating within legal limits, each Sheridan Media radio station's signal is monitored 24 hours a day. In addition, we take measurements of each transmitter's power output several times a day. We check the modulation and carrier levels at least once a week, and twice a year we do an inspection of the transmitters to help prevent any undesired operation.

WHY DOES THE RFI COME AND GO?
If you imagine removing the walls, floors and ceilings of your house, leaving just the wiring, you will see that in your house is a large network of wires. In addition, each electronic device has internal wiring that becomes part of that network. Also, as your house is probably part of the power grid and phone system, it is also part of a larger network of many potential antennas. Any improperly grounded or unshielded device in that network could potentially pick up RF and transfer it to other parts of the network. The RFI can change as devices are turned on and off, plugged in and unplugged.

WHO IS RESPONSIBLE FOR PREVENTING RFI?
The FCC requires almost all consumer electronic equipment to have the following notice attached:

"This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received. Including interference that may cause undesired operation"

Almost all electronic equipment can potentially pick up undesired RF. It is usually up to you to determine which device is at fault, then contact the manufacturer if you feel it is unnecesarily picking up RF.

HOW DO I TELL WHICH DEVICE IS THE SOURCE?
The most common RFI problems are with phone systems. Many houses have multiple phones and other devices (modems, fax machines, security systems, satellite receivers etc.,) all connected to the public phone system. If one of these components picks up the RF and converts it to audio, everything on the system can appear to be affected. The trick is to find out which device is the instigator.

To locale the culprit, unplug everything from all of the telephone jacks in your house. Next, take a single, cord-type phone (not a cordless), and test each phone jack, one by one. In most cases, you will discover that the phone works correctly and the RFI is gone. If you still hear the radio on the phone on all of the jacks, the telephone you are using may be at fault. Try a different phone and see if the problem goes away. If you still hear the RF no matter what phone you try, there may be trouble with the telephone system. There is more about this below.

If the RF is gone on the phone now, start to plug in more devices, one by one, and check the phone each time. Eventually, the RFI should return and you will have discovered which device is causing the trouble. Contact the manufacturer and see if they can provide a solution. If they can't, you may want to try installing an RF filter near that device. Most companies that work with phone equipment can get these for you. Make sure you get the correct one for the frequency being received.

If you discover that the RF remains no matter what devices are plugged in, there could be trouble with the telephone system. Sometimes, when the system is being expanded or other modifications are being made, parts of the system may not be completely terminated. During these periods the public phone cable may act as an antenna and bring the RF in to your building. Ask the phone company if they are doing any work in your area. If they are, the RF noise should be gone once they complete the job.

Another potential source of trouble is improper grounding within your building. To properly protect from electrical noise, all outlets should ground at a single spot. If there are multiple grounding points in your building, there could be potential between different outlets and possible ground loops. If you suspect this is the case, have a qualified electrician check your building.

HOW DO I PREVENT RFI?
Proper grounding and shielding is crucial to keep out undesired RF noise. Standard phone cords and most home stereo cables are NOT shielded. Whenever possible, use shielded cables, or run them through metal conduit, and make sure everything is properly grounded at a single point.