Radio Communications and Electronic Warfare: Weapons that Do Not Kill...Directly
Sometimes, the most important tools on the battlefield are not ones that kill, or even wound. They are the tools and technologies that make it possible to fight the battle, or that give advantage to the side that uses them most effectively, even if they don't fire a bullet or otherwise directly cause injury. Likely the most important tools of modern warfare, that began to change the shape of war as early as the mid-19th century, are communications technologies. From the telegraph and its lower-tech but ingenious sibling, the heliograph, through radio and ultimately satellite and wireless networking, real-time long distance communications made things possible in warfare that couldn't even have been imagined a few decades earlier.
Prussian armies ran telegraph lines as they advanced, allowing constant communications between the general staff and the troops in the field during the German wars of unification. Wired communications using Morse code, still provided rapid and effective communication, and thus coordination. This fit in with Prussian, and later Imperial German war doctrine, calling for smaller independent armies, operating in coordination, to outmaneuver enemies
Telegraph also important in the US civil war.
British began using the heliograph in the mid 19th century; remained in use, at least as a reserve, until the 1960's. Heliograph uses an arrangement of mirrors to flash out morse code in light pulses, allowing manual light-based communications across long (line-of-sight) distances on clear/sunny days.
Wired telephone lines became critical during the world wars, for communicating between the front and HQ. The Signal Corp was tasked with running and maintaining the phone lines, providing the officers with their eyes and ears. Radio was available, but was clear channel, and thus would be easily intercepted by the enemy. Radio was useable by broadcasting morse code, through a cipher, like with the ENIGMA machine.
What is radio? Essentially, radio is electromagnetic waves that radiate from a transmitter (which could be natural, like a star, but for our purposes will be an electronic device), and can be detected and demodulated by a receiver. This is almost like a high frequency sound causing a metal or glass object some distance away to vibrate in harmony. Meaningful information, including analog sounds (speech, etc) and digital data can be encoded and transmitted using radio waves, allowing information to be sent at light speed, and thanks to some equally astonishing capabilities of both radio waves and the Earth, that information can even be sent all around the world: the electromagnetic fields of the Earth, the ionosphere, can cause radio waves to bounce, which can be used to send a transmission around the curvature of the earth, allowing for near-instantaneous communication long distances, even outside of line of sight.
Radio waves travel line-of-sight, and in a diffusing pattern, relative to the shape of the antenna (antennas can be directional or omnidirectional). Due to the nature of radio waves as electromagnetic radiation, there will be many signals occupying the same space, creating interference, or noise. Just like talking louder in a noisy room can help you be heard, we can increase the clarity and strength of our radio transmission by increasing the Power, following the equation P = IV (Power in Watts = Current X Voltage) or P = I^2R (Power = Current squared times the resistance)
An important concept when understanding radio is wavelength, which is the distance between successive peaks in the electromagnetic wave. A related concept is frequency, which is the speed of the wave. The longer the wavelength, the further the wave will travel, but the less information can be encoded. Wavelength and frequency have an inverse relationship, Wavelength = c / Frequency (where c = the speed of light).
There are many types of antennas, with different capabilities depending on the shape and positioning. The most basic type of antenna is the dipole antenna, which is essentially a wire with the feed point in the middle; it transmits and receives in all directions except in the direction of the wire itself (the poles). A similar simple antenna is the monopole, or whip or mast. This is like your car antenna, or the simple antenna on a portable civilian radio. Other types of antennas, including radio dishes, are capable of concentrating directional signals to send or received with higher wavelengths, and greater directional distances. These are particularly useful when talking to spacecraft and satellites.
When Marconi and others first discovered and harnessed the use of radio waves, while groundbreaking technologically, it had a major drawback for military use. Analog voice transmissions were clear, and could be listened to by anyone with a receiver set to the right frequency. The first useful solution to this weakness, as was used in the world wars (particularly World War II), was for radio operators to broadcast in coded language, and even better to use Morse code, in which the letters of the message were first put through a cipher. The receiver would need to transcribe the Morse code, and then decode the cipher before the message could be read.
During World War II, communicating using enciphered morse code was a famous part of the war, and along with the infancy of RADAR, a major part of how Electronic Warfare was waged. Most nations had some system of ciphers and codebooks, but the Germans were particularly famous for their semi-computerized cipher system, the ENIGMA machine. With ENIGMA, an operator set parameters based on a daily codebook, and then typed a message into the machine, which outputted the encoded message. The encoded message was then transmitted by a radio operator using morse code. The receiver would need to know the daily settings, and have their own ENIGMA machine, the then reverse the cipher and output the original message. Intercepting and interpreting ENIGMA communications required both a copy of the codebook, and a working ENIGMA machine, and a major objective of MI5 and the OSS was to capture the machine.
Of course, these are all very human intensive interventions to make up for the inherent weakness for analog radio communication for military purposes. The digital revolution over the later half of the 20th century changed that, by making computerized radio possible, which both digitizes, encrypts, and transmits voice communication, and then receives and decrypts on the other end, essentially transparent to the operator.
The Single Channel Ground and Airborne Radio System is the family of interoperable systems used by the modern military for unified communications, making use of computerized technologies to encrypt or otherwise secure the communications. The same basic units, in different configurations, can be used in a man-portable version, or vehicle mounted, including aircraft. SINCGARS support both voice and data communications, including access to the combat internet, and so can be used to transmit mission intelligence to units in the field, as well as provide voice contact to the radio controllers, and to commanding officers.
In order to provide secure communication, SINCGARS include onboard systems for generating or inputing cryptographic keys, for authenticating and interacting with encrypted networks, using the ANCD (Automated Network Control Device); this is not so different than using a certificate manager with public key infrastructure in a civilian IT organization, and automates the process to prevent human error.
Other SINCGARS accessories and components include Computer subsystems, and GPS units, all of which can download relevant mission data from command and make it available to units in the field as needed.
Together, SINCGARS make up the nodes in the CNR (Combat Net Radio), which makes use of SINCGARS and Tactical Satellites (TACSAT), along with Tactical Radio Operators, to connect ground, air, and sea forces together, to coordinate operations and share intelligence in real time. This includes digital links to artillery fire support (AFADTS), which allows forward observers, including aerial assets, to automatically report targeting info to artillery, allowing real time fire effect info. This is critical, as modern artillery can have ranges in the dozens or even 100+ miles. This has come a long way since the days of semaphores and hot air balloons for directing long range and high-angle artillery.
It should be clear that Radio, particularly with encryption and other anti-interception and anti-jamming countermeasures is absolutely critical to the kind of joint operations that a modern military is called on to perform, and preserving control of the electromagnetic spectrum is one of the most important specialized roles in the modern military. The tactics and operations of controlling the spectrum, while seeking to undermine the enemies use of the spectrum is what is termed Electronic Warfare.
Electronic warfare can be defined as any of a number of offensive and defensive applications of the electromagnetic spectrum, particularly operations to assert control of the spectrum or defend against attempts to seize control of the spectrum, and to deny the opposition access to the spectrum.
This can include jamming, locating and disrupting enemy transmissions capabilities, and interception and impersonation of enemy assets, which would be essentially like social engineering or a man-in-the-middle attack in cyber security.
Radio jamming can be as simple as broadcasting noise over a frequency the enemy is using for communication, which of course can be countered by changing frequency. Modern military radio systems like SINCGARS include anti-jamming capabilities such as Frequency Hopping (FH), where the radio network moves through a sequence of random frequencies constantly, managed by the control channel and the computer, so authenticated users notice little to no disruption, but listeners or jammers will be unable to intercept.
Control of communications is essential for modern operations, control of spectrum is critical for superiority on the modern battlefield. Mastery of communications has evolved since the 19th century, and nations that best master communications are at a marked advantage. We see some of this today, in the Ukraine conflict, where Russian forced have been degraded to using clear channel communications and personal cell phones on the battlefield, being intercepted, and eliminated, due to superior COMMS technology NATO provided to Ukraine. Similarly, this remains one of the US Military’s greatest advantages, from our network of TACSAT and our systems of military radios, even as the SINCGARS themselves age (the original design dates back to 1987, and DOD has been in the process of upgrading/replacing the system).
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