The hearing aid that eavesdropped on taxi cabs: Strange but true

Bob Martin
April 10, 2013

I want to tell you a story that I promise is absolutely true! Many years ago, I fitted a hearing aid on John, a 50-year-old gentleman with substantial hearing loss.

The hearing aid was manufactured by Audiotone, a Phoenix-based company. I was familiar with the staff at Audiotone because I went to school at Arizona State University, in Tempe, right outside Phoenix.

After wearing the hearing aid for a week, John came back to see me. I asked, “Are you having any problems?”

“I like it,” he said, “but the taxi cabs are driving me crazy.”

“Oh,” I said, “Do you spend a lot of time in taxis?”

“No, no!” he said. “It’s not that. You don’t understand. When I’m in my house, I hear the taxi cab drivers talking on their radios. I don’t hear the transmission from their home office. I just hear the taxi cabs that use the illegal power boosters.”

I had never heard of “illegal power boosters” on a radio transmitter, and I had no idea what to say. We sat there and talked a few minutes.

Then John yelled, “Doc, Doc.” And he tore the hearing aid out of his ear and stuck it in mine. I heard a cab driver saying something like, “Okay, I’ll be there in 15 minutes. I am coming back from Convoy Street.”

Wow! This hearing aid really was receiving transmissions from taxis!



I kept the hearing aid and called Jim Nunley, who was the head engineer at Audiotone at the time. I know Jim. He is brilliant.

“Come on, Bob,” he said, “I know this chip inside and out. There is nothing–I repeat, nothing–in the circuitry that could possibly receive a transmitted signal. It is impossible.”

I agreed to ship the hearing aid back to the factory so Jim and his staff could check it. Before I did so, just to be sure, I wore the hearing aid for a couple of days and I heard a taxi cab several times. The sound level was painfully loud. Then, to my eternal regret, I mailed the hearing aid to Jim at the factory.

The hearing aid was returned several weeks later, repaired with new circuits. I called Jim and was disappointed to hear that he had checked it carefully, found nothing, and then replaced the circuits.

The magical hearing aid that could eavesdrop on taxis was gone. Now, no one would believe John’s and my story. In 37 years of fitting hearing aids since then, I have never seen anything like it.

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