Watching the “The Crown” docudrama (which is described as historically accurate except for the personal affairs of the Royal Family), there is a scene where a young Prince Phillip goes on a world tour of the British Empire, including a stop at Antarctica. This was the 1950s, as I recall. Yet, his radio broadcast(s) of his expeditions were heard around the world. The show makes this seem like the world was listening in real time.
Besides the practical matter of time zones, what about the physical limitations of radio itself? Was there a network of ground transmitters that acted as repeaters to send such signals around the world in real time? Or, was it recorded and rebroadcast?
The BBC started its Empire Service in the 1930s. It was broadcast on shortwave (aka high frequency). Radio waves in that part of the spectrum (3-30 MHz) are reflected both by solid ground and by the ionosphere, so they can “bounce” up and down between the ionosphere and the ground and, in doing so, achieve very long (easily intercontinental) ranges, curving along the curvature of the Earth.
Back in the service part of my equipment for one job was a portable HF radio about the size of a modern laptop. With an appropriate antenna, which was really just a long wire, I could transmit to radio stations on the other side of the world. No fancy satellites involved.
Those “expensive communications satellites” allow for high bandwidth communications regardless of ionosphere activity. Good luck transmitting real time high resolution video signals via microwave frequencies.
Some bandwidths travelled around the world, some bandwidths had a preference for ionosphere activity. For some frequencies, IIRC, the best time to transmit was when both end of the transmission were in night, or evening, and the ionosphere was more reflective.
But the key is bandwidth. When you modulate a radio frequency with a signal, it creates “sidebands” of the +/- of that signal. Two signals too close together will interfere. Sound broadcasts on AM were typically separated by 30kHz, meaning a sound signal could include frequencies and harmonics up to 15kHz; for FM this was typically increased from 15kHZ to a more ear-friendly 20kHZ for cleaner sound - plus FM was less prone to noise interference. I think the separation for TV video and audio was 6Mhz.
This brings us to the other reason for satellites - with each transmission using a certain amount of the spectrum, there is a limit to the number of broadcasters. It’s bad enough with line of sight FM and TV, or AM which can erratically propagate hundreds of miles at night, but worse with world-wide signals.
With private point-to-point directed broadcasts beamed to satellites, and even more with private wired signals, the overall capacity has no upper limit. (Except yes, there’s a limit to the number of separate signals on a microwave connection; so the limit becomes how focused a microwave beam can be. The equatorial stationary satellite orbit is pretty close to capacity, a decade or two ago IIRC they went from 5º to 3º separation. Plus there’s a lag - 22,000 miles each way means almost a quarter-second lag at the speed of light - fine for “live” TV signals, but not as great for computers.
Today, most intercontinental transmission are by undersea fibre optic cable. Undersea (copper) cables for telegraph go back to the late 1800’s. The problem with using copper cable for voice was that it was even more severely limited in capacity, which is why in the “Good Old Days” long distance was so expensive and complicated.