The “Roger” beep after transmissions from Space missions is @ 2475 Hz for 250 ms. According to everything2, there should be a pre-transmission tone @ 2525 Hz for 250 ms. They are called Quindar tones.
The “Roger” beep after transmissions from Space missions is @ 2475 Hz for 250 ms. According to everything2, there should be a pre-transmission tone @ 2525 Hz for 250 ms. They are called Quindar tones.