Exactly.
Actually, let's look at the connectors:
An RCA connector, sometimes called a phono connector or (in other languages) Cinch connector, is a type of electrical connector commonly used to carry audio and video signals. The name RCA derives from the Radio Corporation of America, which introduced the design by the early 1940s for internal connection of the pickup to the chassis in home radio-phonograph consoles. It was originally a low-cost, simple design, intended only for mating and disconnection when servicing the console. Refinement came with later designs, although they remained compatible.
I've seen RCAs used inside a 1950s tube TV to carry a 10.7 MHz IF signal from one part of a TV tuner to another. (Look up "turret tuner" or see
[Link: modip.ac.uk] to have a clue what we had to go through to receive high frequency signals back then.)
How does this relate to the original question? Well, that RCA cable was perfectly capable of carrying 10.7 MHz ! That is WAY WAY WAY above the audio spectrum. The keys are -- good connectors, excellent soldering (the shield was soldered to the connector's ground all the way around the connector), but most importantly, the entire cable assembly was only about five inches long.
It would work until it wouldn't means that same cable would not have worked if it were, say, three feet long.
