[AlbertCory]

A question about ELF and VLF for whoever knows:

I just finished reading Thunderstruck (Erik Larson, author of Devil in the White City), which I don't recommend. It ineffectively juxtaposes the story of Marconi with Hawley Crippen, a murderer in London whose case became famous around 1910. (I say "ineffectively" because their stories really don't intersect, IMHO) The book goes on and on about all the demos and tests he ran for years and years, to the point of being eye-glazingly boring. All that aside...

Anyhow: at the very end, the author tells us that Marconi discovered near the end of his life that higher frequencies obviate the need for the gigantic transmitters and receivers he'd been using. Yet he never tells us what frequencies Marconi was using! Does anyone know?

[js2]

I loved Devil in the White City so it's too bad to hear that you didn't find Thunderstruck very good.

Marconi was working on developing microwave transmission at the time of his death. Microwave antenna are small but are only good for line of sight transmission.

[AlbertCory]

I found I'm alarmingly ignorant of the development of radio.

People had household radios in the 20s. Marconi was still alive then. From this admittedly unscientific book, he seems to have been resolutely ignorant of other people's work in the field.

[aidenn0]

I think he was using MF and HF for most of his work, but I'm not sure[1]. The story about discovering higher frequencies remove the need for longer antennas lat in his career seems garbled since the he discovered early on that longer antennas allowed for longer distance communication.

1: His first claimed transatlantic transmissions were definitely MF.

[aidenn0]

Too late to edit, but per Wikipedia[1] once the quenched-spark transmitters were widespread, transoceanic transmissions were VLF and LF, marine were MF, and amateur was high MF (above 1.5MHz).

1: https://en.wikipedia.org/wiki/Spark-gap_transmitter#The_%22s...

[AlbertCory]

Wikipedia says he was using "pulses" instead of "continuous wave" which we now use. So maybe the question about "frequency" doesn't even apply? idk

[aidenn0]

Properly it was dampened waves. Pulses go into the antenna, but the antenna is resonant, so waves go out. A bit like hitting a tuning fork. Later on he used RLC resonant circuits for the same effect.