What Causes Phone Static?

by Derek King

The Federal Communications Commission (FCC) defines interference as any "unwanted radio frequency signal that prevents you from watching television, listening to your radio or stereo, or talking on your cordless telephone." In regard to phones, interference prevents reception, causes losses of signal and creates phone static. Understanding the causes may allow phone users to understand the root of their static problems.


The phone typically causes transmitter interference. The internal wiring of the phone may be insufficiently protected with inadequate shielding or filtering. Therefore, the phone is susceptible to receiving unwanted signals. The source of interference may come from frayed or faulty wires that act as an outside antenna for interfering signals, or radio transmitters such as amateur radio or CBs. Cordless telephones use radio frequencies, and they are not protected from receiving transmitter interference.

Electrical Devices

Appliances and other electrical devices plugged into a wall outlet, such as hair dryers, sewing machines, vacuum cleaners, electric drills, heaters and fluorescent lighting, all cause electrical interference. Electrical interference may also cause display screens on advanced mobile phones to be covered with rolling horizontal lines, bars or diagonal dashed white lines. Electrical interference also causes audio static during phone calls.

Poor Connection

Cordless phones feature a frequency range. A phone must remain within that range to send and receive calls with good sound quality. Cordless phones out of the recommended range of use may experience static and faulty call quality, and they may even have call drops. Refer to your cordless phone's user manual to learn the proper distance the device must stay within its base.

About the Author

Derek King is an undergraduate student attending the University of Austin. King was editor-in-chief of his high school newspaper for four years. In addition to online instructional articles, he also creates content for the music and entertainment blog GetFreshKid.com.

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