> In the summer of 1917, he was arranging various types of coil antennas at a receiver test site on the Chesapeake Bay when he accidentally dropped one of the antennas into the water. Strangely enough, the radio receiver connected to the antenna continued to provide good reception even as it sank into the bay.
RF Science is fascinating. Now might be a good time to ask; Does anybody have any recommendations on scientific books/papers/articles on the effects of RF spectrum (all frequencies) on Human Biology and Physiology? There is a lot of nonsense/hysteria out there but i would like to know the actual experimental evidence and science.
The DOD terms are RADHAZ and HERP (Hazards of EM Radiation to Personnel.) There is plenty of literature out there on what frequencies turn you into a microwave oven for cooking your insides, based on your length as a living antenna.
The ARRL has some good writing on RF exposure. Basically everything I've read comes down to treating radiated RF energy as thermal risk. So it's not magic stuff that will give you cancer or cause your cells to turn inside out or something, it's just going to raise the temperature of whatever region of your body the signal is going to interact with. Could be 0.003 degrees C, could be 30 degrees C -- all that depends on the energy involved.
But that's at HF frequencies and above, not this VLF stuff which is somewhat of a different beast. Risks there are probably similar to AC mains power distribution, I would guess: touch it and get a nasty shock, don't touch it and you're fine.
I think my Grandpa worked on the mentioned classified experiments in the late 1950s and throughout the 1960s. He was a Naval Academy graduate with a degree in electrical engineering and spent several years on submarines. He then spent several years working at the Pentagon in late 50s and throughout the 60s (my mother was born in Bethesda in 72).
He took those secrets to his grave. I could never get it out of him what he did that was classified. Although I did find several books and research papers in his basement about sonar and radio communications…
Anyways, great article that gave me a bit more insight into what my Grandpa might have been up to.
computer.rip has dozens of rabbit hole articles that seem to be tied together in an "old tech / weird tech" bundle. I'd love to find a book on similar subjects too.
For someone interested in this topic and happens to pass by, I can highly recommend a visit to Grimeton Radio Station[1], Sweden, which is still operational.
It's crazy that they're using radio frequencies that are within the range of human hearing... Obviously sound and RF are different things, but it puts into perspective how a "high" sound is a very "low" frequency ;)
The extreme lower edge could be said to fall around 7 Hz, where the wavelength of a radio signal matches the circumference of the earth.
Those are rookie numbers. Ok so not the same, but headline made me think of NANOGrav first, which uses minute shifts in pulsar timings to detect gravitational waves in the nano-Hz range[1].
The submission was about subs rather, and quite interesting as such.
The ELF system was found to cause problems ranging from flickering light bulbs to phantom telephone ringing, and the Navy installed additional grounding and filtering on public utilities throughout the area at its own expense—even reimbursing the utilities for administrative costs related to customer complaints.
Yea that surely helped drive some ghost stories and paranoid delusions.
We (as an industry) have repurposed this technology for what's called Electromagnetic Measurement While Drilling telemetry. We break modern drill strings with a "gap sub", which is basically just a piece of iron with a ceramic insulated thread, into a "crappy dipole" which then if we impart 2-30W of power through roughly a Class D amp we can generate a signal that goes through most formations of the earth to the surface from over 5 miles underground from the transmitting source. Transmit frequencies are generally 2-10hz, sometimes pushing 32+hz. It's a fascinating use of the tech. If building in this industry sounds awesome to you, feel free to drop me a line. ken _at_ erdosmiller _dot_ com.
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[ 0.21 ms ] story [ 34.8 ms ] threadI found a slightly clearer diagram of the Cutler array:
https://en.wikipedia.org/wiki/VLF_Transmitter_Cutler#Antenna
is discovery ever intentional :)
1) Extremely low frequency - https://en.wikipedia.org/wiki/Extremely_low_frequency
2) Communication with Submarines - https://en.wikipedia.org/wiki/Communication_with_submarines
An important addendum is the subject of "Underwater Acoustic Communication" - https://en.wikipedia.org/wiki/Underwater_acoustic_communicat...
RF Science is fascinating. Now might be a good time to ask; Does anybody have any recommendations on scientific books/papers/articles on the effects of RF spectrum (all frequencies) on Human Biology and Physiology? There is a lot of nonsense/hysteria out there but i would like to know the actual experimental evidence and science.
But that's at HF frequencies and above, not this VLF stuff which is somewhat of a different beast. Risks there are probably similar to AC mains power distribution, I would guess: touch it and get a nasty shock, don't touch it and you're fine.
He took those secrets to his grave. I could never get it out of him what he did that was classified. Although I did find several books and research papers in his basement about sonar and radio communications…
Anyways, great article that gave me a bit more insight into what my Grandpa might have been up to.
[1] https://en.wikipedia.org/wiki/Grimeton_Radio_Station
I would have to assume that this building is pre-targeted by many megatons of advanced weapon systems.
https://maps.app.goo.gl/w9Sr4YkFbtfKf2Fh6
https://www.navy-radio.com/commsta/jimcreek.htm
https://www.cascadepbs.org/culture/2022/07/jim-creek-harbors...
https://www.historylink.org/file/20778
Those are rookie numbers. Ok so not the same, but headline made me think of NANOGrav first, which uses minute shifts in pulsar timings to detect gravitational waves in the nano-Hz range[1].
The submission was about subs rather, and quite interesting as such.
The ELF system was found to cause problems ranging from flickering light bulbs to phantom telephone ringing, and the Navy installed additional grounding and filtering on public utilities throughout the area at its own expense—even reimbursing the utilities for administrative costs related to customer complaints.
Yea that surely helped drive some ghost stories and paranoid delusions.
[1]: https://arxiv.org/abs/2306.16218 (figure 9)