Why Does Radio Static Go Away Whenever You Touch the Dial?

iStock / iStock

Static is a routine annoyance for those of us who still listen to terrestrial radio. You get up to adjust the dial and, just as you put your hand on the knob or button, the reception clears up. You sit back down and, a few seconds later, the sound crackles again. If you have my luck with radio reception, the signal probably breaks up again right as Neil Young tears into the solo on “Like a Hurricane” or Ira Glass gets to the point.

Why is it that human contact seems to fix radio signals for an annoyingly brief instance?

To understand the actual reason, it is important to first understand what causes static in the first place, says Davin Huston, a clinical assistant professor at Purdue Polytechnic Institute’s School of Engineering Technology. “Your radio is a dimwit. It doesn’t understand the difference between music or talk and background [electronic] noise in the area.”

Radio receivers constantly pick up on electronic activity in the vicinity, from things such as microwaves and lightbulbs, and interpret it as a signal, creating interference. A human body can block competing electronic activity and allow the receiver to "concentrate” on the radio signal it is “supposed” to be picking up, says Huston. Of course, when a person walks away, all those background distractions return and the sound cracks up again.

In order to block distracting electrics and improve your reception, Huston endorses this sweetly old-timey list of tips from WERU, a noncommercial, community radio station struggling to reach as many listeners around Hancock County, Maine, as it can. They include: keeping your radio in a high location, like a bookcase; using a rotorized (pointable) antenna instead of a stationary one to point at the origin of the signal; or even connecting your radio to a set of TV bunny ears (provided you can find a set in a Goodwill or grandparent’s attic or somewhere) and put them in a tree or attic.

If those sound difficult, they're still certainly easier than listening all night with your hand on the dial.