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Life & fun · December 15, 2015

Recreate NASA's Apollo Space Beeps (Quindar Tones) with Web Audio

How to recreate Quindar tones - the high frequency beeps used in the Apollo missions

Recreate NASA's Apollo Space Beeps (Quindar Tones) with Web Audio launched on December 15, 2015 with 33 votes, #1,735 of 3,505 launches that month and more than 90% of that year's launches. The site was still online in September 2026, 10 years on.

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In plain words

This resource explains how to recreate Quindar tones, the distinctive high-frequency beeps NASA used during Apollo missions to control ground transmitters. It details the technical specifications: a 2525Hz sine wave to activate transmitters and a 2475Hz tone to deactivate them, each lasting 250 milliseconds. The guide uses web audio technology to generate these historically significant sounds. It's designed for space enthusiasts, audio developers, and anyone interested in recreating authentic Apollo-era communication signals.

written from the facts on this page · September 2026

From the sources

They are known as Quindar tones (named after Quindar Electronics, Inc - the manufacturer of the tone generating equipment) and were used by NASA as part of a system designed to turn on and off transmitters on Earth, enabling CapCom (based at mission control, Houston) to communicate with the astronauts. The system consisted of an intro and outro tone - each one a single sine wave lasting 250ms. The intro tone, which turned the transmitters on, had a frequency of 2525Hz, and the outro tone (which turned the transmitters off) had a frequency of 2475Hz. So, to talk with the astronauts, you needed to push and hold a button. When the button was first pushed, the intro tone would be sent, then you…from outputchannel.com

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