Parabolic Microphone

Parabolic Microphone Team

In September, 2015 three members of the Santa Clara Sheriff’s Search and Rescue Team responded to a mutual aid call for a lost hunter in Madera County. As the first full day of searching drew to a close, none of the six mountain rescue teams had found any sign of the hunter, who had now been missing 48 hours at 8000 feet. At dusk, the Santa Clara team went out on a prominent ridge to call for the hunter. They heard a faint response, but couldn’t tell if it was the hunter, another team in the distance, or just a bird calling. At that point, the team thought it would be very useful to have a parabolic microphone, which most people know as the sound amplification devices seen on the sidelines of televised football games.

Fortunately, it was the hunter calling back. He made his way to the ridge, and was soon reunited with his family. But the team did not forget about the microphone idea.

A generous company provided three parabolic microphones, and the team conducted a rigorous study to determine whether the microphones enhanced the ability of searchers to detect and comprehend hidden callers. The results are very clear. In calm weather, unaided listeners can detect and comprehend more than 50% of callers out to 1200 meters. But use of a 26 inch parabolic microphone extends this to 2500 meters, or more than 1.5 miles. This means a single 360 degree arc would cover almost 20 square kilometers.

The full study was published in the Journal of Wilderness and Environmental Medicine, and is available here for free.

Ours is the first team in the country to use a 26 inch parabolic microphone in Search and Rescue. The team has made a special pack that allows us to carry the microphone into the field. Our standard equipment also includes a megaphone (to elicit a response from a subject) and satellite communication equipment so we can operate even if a communication system has not been set up.

The Parabolic Microphone Specialty Team stands ready to respond to mutual aid calls in situations where a subject might be responsive.

We have also created a seven minute video about the study and how we use the parabolic microphone in searches for lost people.