Days
Commentator
We live in a digital world that takes the old analog signal and digitalizes it. That process is far more complicated than anything I will post here, but because we live in that world, we understand what digital television is. Originally, television was created by taking a series of pictures in rapid succession (guess what: today's television is still created the same way) and then displaying that stream of pictures (the signal) on a monitor. In the 1940's we figured out how to broadcast television signals the same way we did/do radio signals. Television signals required more bandwidth and carried both picture and sound. Next we learned how to send the television signal from station to station with parabolic dishes. The dishes create a beam which then can be sent from "hop" to hop... radio towers with 8 foot dishes were spaced 25-35 miles apart utilizing "line of sight" technology; which just means the signal beam was aimed at the 8 foot dish on the next tower, which then beamed it to the next tower; each tower had a 8 foot dish to receive the signal and another 8 foot dish to transmit it on again. The frequency used was microwave. Microwaves are the same size as a molecule of water, hence they oscillate the water molecule (cook it) and therefore the signal is easily interrupted by weather. Once the signal was transported from one station to the next, it could be broadcast in another region. When the signal is broadcast, it is sent out in a wave in every direction, the same as light from a star. The analog signal had a broadcast range of roughly 100-200 miles depending on the amplitude. After the signal dissipated over enough distance, the signal would "break up" or simply become too thin to receive by a receiver. In theory, an electromagnetic wave will carry into infinity, in practice, it has very definite range limitations. However, when the signal is transmitted as a beam from a parabolic dish, the signal holds together for much greater distances. And when that signal is pointed towards the heavens, it only has to penetrate 10 miles of weather (the biosphere) before it reaches an unencumbered environment. The signal is still an electromagnetic wave, so it will eventually spread out and dissipate. In the 1960's we learned to go to larger dishes (15-20 foot) and stronger signals and was able to transmit between earth and satellites orbiting 300 miles+ above the earth. Then, in 1964, we figured out how to get a satellite to work in the Clarke orbit (22,000 miles out) which is a geo stationary orbit, which means the orbit remains in a fixed relationship to a spot on earth. The very first successful satellite launched in this orbit was fixed over the Pacific Ocean and the very first LIVE television broadcast (signal) to be transmitted across the Pacific Ocean was the 1964 Tokyo Olympics. In order to transmit that signal to the Clarke orbit and to fetch it back again, we built 85 foot dishes. That was cutting edge analog television technology in 1964. In 1965, the Apollo space program ordered up two more 85 foot dishes from the same industry to be used to send and fetch the same analog television signal to/from the moon. The moon is 11 times farther away than the Clarke orbit. In the days of analog, that was called, way out of range. However, the 1964 satellite fixed over the Pacific Ocean was in perfect operating range... and was already functional... as long as the ground bases were Pacific Rim, which they were. The ghost images of Apollo 11 were the result of the complicated broadcast signal that tore the signal apart and packaged it into a smaller bandwidth; that signal had to be reassembled when it was received... it took them a mission to get that process down... it was a lot more complicated than mere tuning. The common misconception is that the ghost images resulted from being out of range... as in, the moon was out of range. Actually, when you were out of range, you get no signal: you get fuzz... if you were barely in range, you would get a faint signal mixed in with the fuzz (they called it "snow") but what Apollo was getting was a strong signal that double imaged on them... they were well within range... of the Clarke orbit.