I ended up owning some of those cabinets after they were sold via salvage auction and grew up learning Ham radio from operators in NW Australia that spent time tapping the VLF (Very Low Frequency) comms to nuclear subs for traffic analysis.
> Covering 1000 acres, the VLF antenna array is the largest in the world.
> The antennas themselves are large spider-webs of wire, supported like a tophat on thirteen steel towers. The towers serve no other purpose than to support this tophat arrangement. The center tower, Tower Zero, is the highest manmade structure in the Southern Hemisphere. It rises to an awesome height of 1,271 feet. The other towers spread out in two concentric rings around Tower Zero. The inner ring of towers is 1 195 feet high and the outer ring is 996 feet high.
> Buried in the ground beneath the antenna is 240 miles of bare copper wire which comprises the "ground mat".
> The power plant located in area "A" is one of the largest presently operated by the U. S. Navy.
> It is made up of six diesel engine driven generators each possessing the capability to produce 3,000,000 watts of power. This creates a total plant capacity of 18,000,000 watts, enough to supply the electric needs for a city of 12,000 people. At present this plant is committed to provide the total power for areas "A" and "B".
There are levels to how much you can push given atenna sizes and amount of gear at either end - the submarine rates are the basic most reliable with least equipment type of transfer rates (as I recall - I was literally barely a teenager at best at the time and learning radio | electronics | etc for the fist time, after which I went more into a theory direction).
It would seem I was recalling frequency-shift keying modulation rates:
My Dad was in a radar picket ship in the Pacific in 1960 and one of his favorite stories was not being able to raise Treasure Island in SF about 100 miles out, but having no problem conversing with Bremerhaven, and ultimately using USN facility in Bremerhaven to relay messages back and forth with Treasure Island.
https://www.navy-radio.com/commsta/holt.htm
I ended up owning some of those cabinets after they were sold via salvage auction and grew up learning Ham radio from operators in NW Australia that spent time tapping the VLF (Very Low Frequency) comms to nuclear subs for traffic analysis.
> Covering 1000 acres, the VLF antenna array is the largest in the world.
> The antennas themselves are large spider-webs of wire, supported like a tophat on thirteen steel towers. The towers serve no other purpose than to support this tophat arrangement. The center tower, Tower Zero, is the highest manmade structure in the Southern Hemisphere. It rises to an awesome height of 1,271 feet. The other towers spread out in two concentric rings around Tower Zero. The inner ring of towers is 1 195 feet high and the outer ring is 996 feet high.
> Buried in the ground beneath the antenna is 240 miles of bare copper wire which comprises the "ground mat".
> The power plant located in area "A" is one of the largest presently operated by the U. S. Navy.
> It is made up of six diesel engine driven generators each possessing the capability to produce 3,000,000 watts of power. This creates a total plant capacity of 18,000,000 watts, enough to supply the electric needs for a city of 12,000 people. At present this plant is committed to provide the total power for areas "A" and "B".