Electronic Warfare (EW) is one of the most recently adopted modes of combat, with only the aircraft following the radio into military service. Just like the aircraft, the radio (and the myriad variations and technologies extending from it) has become one of the most powerful weapons in existence, so indispensable in the field and such a powerful force multiplier that the concept of waging war today without it is inconceivable.
The first type of EW ever performed was simple passive listening to a target's communications, an application still practiced with great zeal today (and not only by the military.) Since then, the art of EW has broadened and branched out to such a degree that each aspect has almost become a completely separate discipline.
There are two main aspects to EW, as there are to all of the military arts; strategic EW and tactical EW. Strategic EW involves largely passive activities one performs to observe their opponent's capabilities and intentions, while tactical EW involves actively engaging enemy troops in the electromagnetic spectrum in a way that will increase your chances of killing them, or to make it harder for them to kill you.
Strategic EW includes:
- Listening to enemy communications. This involves more than just sitting in front of a radio and listening, it also involves the machinations one must go through to be in a position to hear the communications, and have the ability to translate the language and break the codes involved. Having submarines tap underwater cables, orbiting satellites with microwave receivers over the enemy's country, and stationing troops with log periodic antennas on mountaintops along the target's border, or on ships at sea off their coast.
- Developing better weapons. Research for better weapons is a strategic activity, whether it is for a better bullet or a better way to make your airplanes invisible to enemy radar. Stealth technology, better, smaller, and more rugged encrypted radios for your soldiers, and advanced radar systems that will enable you to better spot incoming missiles and aircraft are all aspects of EW research.
- Monitoring enemy elecromagnetic emissions. Similar to listening to their communications, this involves finding out what frequencies enemy radar operates on, the type of energy pulse, how far they can "see", how they acquire a target, and what type of weapon system the signal is associated with (so you know that if you detect type "a" radar energy, the enemy probably has a type "a" missile on a launcher nearby.)
- Keeping an eye out for the bad guys. Pointing radar at the sky to get an early warning of any enemy attack is one of the oldest types of EW, used since WWII. Ditto ship radar to see enemies at sea. There are even small radar kits for combat troops to detect enemy soldiers. (These can also be considered tactical applications, but there is always a bit of overlap in every combat discipline.)
- Computers. This is a very new aspect of EW, where you try and hack your enemy's computers while preventing them from hacking yours. Attacks can include denial of service attacks, viruses, or simple(?) password-guessing. Defense involves stable operating systems with good anti-virus software and the use of firewalls both physical and electronic.
Tactical EW includes:
- Radio direction finding (RDF). This is using the enemy's radio transmissions to find out where they are by triangulating on the signal. The benefits of knowing where your enemy is are obvious. This can be coupled with radio traffic analysis to determine what kind of troops they are, and what level of command they are operating at, to better allocate your combat assets such as artillery fire) to destroy the most important ones first.
- Radio intercept. This is listening to the enemy's tactical radios. It is often performed in conjunction with RDF, to provide the data to perform analysis on.
- Radio (and Radar) jamming. This is the most fun and most dangerous job in tactical EW. Jamming radio involves transmitting lots of power in the same frequency to overwhelm the radios of the parties involved. This can be done to simply disrupt communications, to prevent orders from being transmitted, or it can be done to make the enemy thinik that their encrypted comm gear is acting up, making them transmit in the clear so you can eavesdrop. The dangerous part is that you are incredibly easy to detect, since you are puttng out so much power. If they manage to find you through radio triangulation, a volley of artillery shells would shortly follow the discovery, and the jamming team wouldn't know about it until the rounds fell. During the Cold War, US military jammer teams in Germany used to practive moving around a lot very quickly. This can also be done in the air to jam enemy radar, and the aircraft (US jammers and Ewar planes have an "E" in their model designation.) that do this for the US Air Force are called "Wild Weasels", protecting groups of aircraft from enemy radar during combat missions. (The Navy uses a carrier-based jet called the Prowler for this.) The concept also extends to any missile-jamming gear an individual aircraft may carry.
- Electronic Spoofing. If you can make the enemy think there are more of you than there are, or that you are in a different location, then you have an advantage. Aircraft have often used variations on radar jamming to create false images on enemy radar screens, to confuse the situation. Sometimes drone aircraft are launched that have the radar and radio signature of a real aircraft. This is done to trick enemy ground-defense radar into exposing themselves, since one tactic a radar site uses to avoid getting an anti-radiation missile is to only turn on their tracking radar when they think a target is coming.
- Physical countermeasures. Stealth technology involves using materials that reflect radar badly, as well as shaping the object to be protected in such a way that reflections are directed away from the transmission point, minimizing the radar echo needed for identification. One can also block radar by dropping strips of metal, called "chaff", between the aircraft and the radar trying to locate it. The key to tactical air combat radar countermeasures isn't so much to prevent the enemy from seeing you (after all, they know that you are there in a dogfight, or when you are bombing their position) but to prevent their radar from locking on to you long enough to guide a missile strike. This can be extended to infrared jammers and flares to counteract heat-seeking missiles.