The world's largest "radio" station (2005) [pdf] | Hacker News Reader

The world's largest "radio" station (2005) [pdf]

pages.hep.wisc.edu

Also of interest are the Nightwatch planes for use as mobile command posts in the event of a nuclear strike. They are able to trail a 5 mile long cable to act as a massive transmitter to also contact submerged ballistic missile submarines.

https://en.wikipedia.org/wiki/Boeing_E-4#Lower_lobe

Also the Emergency Rocket Communication System [1], ICBMs with 1 kW UHF transmitters instead of warheads to broadcast prerecorded messages of up to 90 seconds in case other means of communication became unavailable. This one would however not reach submerged submarines.

[1] https://en.wikipedia.org/wiki/AN/DRC-8_Emergency_Rocket_Comm...

The ultimate low tech fallback from the UK, noone knows exactly what they say but there's lots of educated theories.

https://en.wikipedia.org/wiki/Letters_of_last_resort

Maybe "if you definitively learn that the Russians nuked London and WA DC, nuke the Russians"

One also must wonder what the submarine commanders thought of receiving new letters from the new Prime Minister after only 44 day of Liz Truss. If she even had time to write the letters and give them to the MOD.

The Tupolev Tu-142 Bear J (a variant of the TU-95) also has this capability:

https://www.globalsecurity.org/wmd/world/russia/tu-95-varian...

The BBC like to get all excited about these aircraft when they do a fly past in international airspace:

https://www.bbc.co.uk/news/uk-scotland-north-east-orkney-she...

The Soviet/Russian Perimeter (aka Dead Hand) second-strike system uses rockets with transmitters flying cross-country to alert the Russian missile fields in case of a decapitation strike.

https://en.wikipedia.org/wiki/Dead_Hand

There are some Amateurs who’ve used the 2200m and 630m wavelength bands. Mostly using Morse Code, FT8 and WSPR modes as they are narrow bandwidth weak signal modes.

https://youtu.be/FuugH6jn9rc

https://www.qrz.com/db/?callsign=dl4eai

In fact some of them appear to be transmitting FT8 even today.

https://pskreporter.info/pskmap.html?preset&callsign=ZZZZZ&w...

2200 meter is LF (30-300kHz). Used mainly with huge coils and low power (1W EIRP). then there's VLF (3-30kHz). Then there's ULF (300Hz-3kHz) Then there's ELF (below 300 Hz), used by the stations in question. To put things into perspective.

Speaking of VLF, SAQ will broadcast on 17.2 kHz on July 2nd. You can pick it up with a soundcard directly (not using a DVB-T chip) depending on your location and use of antenna.

While I was passingly familiar with the system previously, this came as a bit of a surprise: "...faculty and researchers at the Michigan Technological University (MTU) School of Forestry and Wood Products have found that the Project ELF’s antenna grid makes the trees grow faster."

That's interesting that it might have an impact on plant life. What about animal? Whenever I hear about ULF/ELF, my mind immediately drifts to the Bryan Cranston "X-Files" episode "Drive" [1]:

> Mulder realizes that Crump is suffering from a painful sensation of pressure building in his head and that the only way to alleviate this pressure is to drive west. ... [Scully] then discovers a U.S. Navy antenna array emitting ELF waves stretches beneath their property. Scully deduces that an abnormal surge in these waves somehow caused a rising pressure in the inner ear of the nearby inhabitants. Westward motion and an increase in speed seem to be the only thing to help ease the pain of the increasing pressure

[1] https://en.wikipedia.org/wiki/Drive_(The_X-Files)

That's interesting, did they give the mechanism for how the antenna grid accelerated vegetation growth or was the conclusion obtained through statistical analysis?

This is an interesting, but older document dealing with stations going down to a couple of Hertz. The lower the frequency, the larger the antenna and therefore the station needs to be.

Currently probably the HAARP station[1] in Alaska would qualify as the largest radio station. It goes down into the 0.1 Hz range. From my limited understanding it is only possible to do so, because it basically utilizes the athmosphere itself as antenna.

[1] https://en.m.wikipedia.org/wiki/High-frequency_Active_Aurora...

You can actually receive those 3-30kHz signals (which are still being broadcast around the globe today) with a garden variety soundcard, as long as you have a suitable antenna (which actually isn't that hard to build, since you don't need a particularly efficient antenna to receive signals). Helps that you can get sound cards with ridiculously high SNRs (compared to say, regular radio receivers) for dirt cheap.