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RF WARFARE (1): TROPO and OTH RADAR [1]

['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.']

Date: 2024-08-13  

This is part 1 of a possible multi-part series on the use of RF (radio frequency) technology in modern warfare, with particular reference to the Ukraine War. I’ll try to write in layman’s terms; please note, I’m an engineer with specialisations in this and counter-surveillance, so I apologise if it gets too deep into technology.

The “three C’s” are critical to modern warfare: Command, Control, and Communication. Let’s examine the last of these first: Communication. The requirement is NEAR to FAR. NEAR could be inter-unit or unit-command battlefield comms. FAR could be a maritime or long-range aerial drone. In each case what’s required is security from eavesdropping, reliable communication, and resistance to jamming. Here, I’m going to discuss FAR.

In the post-WW2 years, the military required a method of long-distance communication that was reliable, hard to intercept, and hard to jam. HF (short wave) radio is highly susceptible to interference and jamming; not only that, but the height of the reflective layers (eg ionosphere) changes with day/night, season, and sun activity. I took part in an experiment around 1971 in which we used two high-power shortwave broadcast transmitters to heat part of the ionosphere, rendering it useless for reflecting radio signals.

“Tropo” as we call it, is not suitable for man-portable use. It requires a small ground station, one such as the main image above.

Imagine a scenario in which your enemy is jamming your HF communications and has taken out your satellite. Tropo still works. The beam is scattered in the troposphere and part is refracted back to ground, while the rest passes through into space.

(Related technologies: Meteor Scatter and Moon Bounce)

Now suppose you are controlling a drone that has to penetrate 1000 Km of enemy territory to attack an airfield — as has recently been seen. A tropo receiver on that drone will allow it to continuously receive commands — and react fast, without the delays of satellite links. So, ideally, you’d want a Starlink terminal AND a tropo receiver. As long as the satellite link stays up, fine. But when it doesn’t you can fall back on tropo for the command channel.

OTH (Over The Horizon) radar dates back to the Cold War. Installations such as the DEW Line (Defence Early Warning) used high-power HF transmitters that bounce transmissions off the ionosphere (see image above). Reflections from launched missiles return via the same path. Using Doppler technology (the same principle as a police radar gun) velocity can be calculated. Such systems are obsolete now due to the advent of satellite surveillance — but satellites, of course, are vulnerable. The DEW was obsoleted in the 1980s and replaced by the North Warning System, which comprises L and D band radars.

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