Electronic Warfare

by HOMA

This article covers only the terrestrial forces (what is normally called army) and not air force or navy.

The term Electronic Warfare (EW) has existed in the army for at least 60 years, but it evolved dramatically only in the last 25.  Digital Warfare was a sub-department of EW but in the last eight years in most countries (at least the ones that have the know-how) it is becoming a division itself.

We are not going to bother with Digital Warfare (DW) since most of its techniques are known to you.  It is mainly hacking.  Maybe sometime later.

EW is separated into two main categories, Passive and Active.

Although both are really important, Active EW is not really appreciated since it is mostly damaging to both parties.  And since it is easier to describe, we will start with this.

Active EW:  Has the intention of blocking enemy communications in any way  Most known techniques are Frequency Blocking, Spectrum Masking, and Poisoning.

Frequency Blocking:  If we have managed to find out the exact frequencies the enemy communicates with on either voice/data, we fill that channel with noise in order to disable that communication channel.  When doing that, that specific channel is inaccessible by either party.

Spectrum Masking:  By Spectrum Masking we block as much of the spectrum (frequencies) as possible.  By doing this we disable all wireless communications for all parties.  This should be done only when it is of extreme importance and if we are able to communicate by other means (such as cables).

Poisoning:  This technique is extremely difficult to use.  It requires a fluent speaker of the enemy's language, the proper air-codes and code names, and in the case of digital transceivers that send a signature - that exact transceiver's signature.  Although it is extremely difficult, there are two cases where it is easier to handle, either during peace in quite remote locations where the enemy is away from their command post, or during a battle when lowly trained personnel use the radio equipment.

Passive EW.  Passive EW is all bout information retrieval.  The Passive EW units are always operational, during peace and war.  They are fast to deploy (most of the time they do "on-road" interceptions) and highly mobile.  Their main drawback is that they are extremely vulnerable, since they are manned by a maximum of three persons with the exception of a unit that is acting as Active/Passive, in which case the count goes to five.  (There are really small units of just one person.  But these units are capable of interceptions of only really inferior technological enemies.  There are many crypto devices that weigh more than 50 kg, add the weight of a light transceiver 15 kg (15 Watts), a small antenna [3 kg], cables [5 kg], and you have a small rack that can intercept transmissions from equipment before 1994.  There are special attack teams though that have limited equipment that can be used after they manage to get a hold of "inside" info.)  No Active/Passive Unit is allowed to be out posted during battle.

Passive EW (Peace):  Since the units have to be placed near the enemy, it is of huge importance to camouflage them.  The most used and successful camouflage is to position them inside civil areas and best inside densely populated areas.  The main drawback is interference by domestic appliances (mobile antennas, radio/TV stations, police, airports, ports), but since most operate on low frequencies, we have only to worry about the "noise."  Positioning Passive EW inside cities is safe, since they do not transmit and their signature/feedback is extremely low, making them almost invisible when mixed with the domestic noise.  From these locations the units intercept as many signals as possible.  The units record everything of importance (they should be educated in the enemy's language) and log as much info about the transmitter (frequency, time, transmitter signature, analog/digital, code names, location) as possible.

In the case of an analog transmitter, there are specific patterns that it transmits, mainly due to hardware alterations with the voice/data, that can be used as an identifier.  With a digital transmitter we have to "break" the transmission in order to create a signature.

The transmitter is located using a technique known as triangulation which needs three different units (minimum two) in various locations or one stable unit and one mobile.  It is however common to have more than five units triangulating the same target.  I have seen targets pinpointed in less than one minute by the cooperation of eight units where the target's distance was more than 300 km (not in an exercise).

The recordings are either translated locally or sent to the unit's command post for translation and then destroyed.  All the translations are sent to the command post for further analysis.  Even the slightest info can be useful after correlation.

There are also outpost units that are located in rural areas and are easily identified by the enemy.  These units acquire the most useful info during peace, since they are mostly located beside the enemy border.  The drawback is that although they are manned with the most capable stuff, they are also the disposable ones since there usually isn't enough time to Pack and Go.  Many times they are used as a type of front line with artillery support.

Passive EW (War):  During war, the units perform the same tasks and in addition they become mobile.  This minimizes the ability to locate targets, but a properly "tooled" unit can intercept everything in a radius of 80 km and transmit in real time raw or translated material (translation on the move is difficult for small units since it is common that the most disposable person is also the driver and translator).  There are cases in which a Passive EW mobile unit can act as an info hub for terrestrial forces although this is usually done by stable units.

Passive EW equipment:  Because of the lack of firepower the units need to be mobile and since the equipment is of substantial size and weight, small vans are used.  The van's back is a small room called Faraday's Cell.  This room in a perfect world should not transmit anything, no radio waves, light, infrared, nothing.  Passive EW is based on its stealth abilities.

Inside the room, you can find wide area receivers which have a vast range of frequencies.  They are made only for the army and usually are comprised of many smaller ones that cover smaller ranges.  In addition you can find digital-to-analog and analog-to-digital converters, mixers, demuxers, at least one transmitter, computers, crypto devices (in black box form and in software form), antenna kits, signal amplifiers, spectrum analyzers, recording media destroyers/sanitizers, and media recorders (magnetic media is quite common since it is easy to destroy).

In the event that the unit is active, there is also a powerful transmitter connected to one of the computers.

The OS used from what I've seen is UNIX-based with some instances of Solaris, although I know of at least one country that uses Microsoft's Windows 2000.

The software used is mostly audio related and some of it is commercial.  The most needed software type is audio filters, although these are created by the army in most cases.  There is a "procedure" in which an area spectrum pattern is acquired in order to identify the normal "noise" of the area and then easily remove that from the recordings.  It is used also to make an assumption of a transmitter location by comparing area patterns.

Notes

Poisoning was heavily used during the 1950s and 1960s mainly for "ejecting" fake information to the enemy, usually trivial info in order to check our own ability of intercepting.

Passive EW units have a wide ability of transferring information in case of emergency and keeping it safe, by even using steganography to import info to public media, like the public phone system and others.

It is essential that all forces "trade" information with each other and the General Command Center is the major data analyst.

Passive EW units intercept anything wired/wireless from transmitters to mobile phones.  During the 1990s some basic data analysis was done on site by the use of automated systems (software).

It is of critical importance that the enemy doesn't know what we know about him, even though he knows we intercept.  Many "mistakes" happen in order to sustain that.

Other than audio, units intercept and transmit other media like video and images.

Big Note

Cryptography adds too much overhead to wireless communications and requires more expensive equipment.

To accommodate for this, frequency hopping is used in line with low-bandwidth encryption that varies from the cheap 50-bits to the expensive 256-bits (expensive mostly in bandwidth).

Every country that uses frequency hopping creates a table of hops (frequency matrix) that is also used as the key most of the times and distributes this to all of its units (not only to EW).  This table resides in the transceiver's memory and depending on its hop ability it cycles through them, thus breaking audio/data into small chunks, and transmits.

The difficult part in intercepting FH transmissions is not the encryption but finding out the hop table, and synchronizing the receiver to it.  The easiest method is acquiring the tables from the enemy.

I hope the information posted here is of educational use to you.  I am sorry if I made any mistakes.  I am not sorry for being brief but sharing more could identify procedures that would jeopardize my country's and other countries' safety.

As a note it is quite easy to find operational manuals over the net for various army tactics of different countries, but fortunately these mostly are outdated or fake.  Keep in mind that most really important information is kept in such high levels of secrecy that only highly ranked officials have access to it on a need-to-know basis.

Also do remember that the army trains personnel by repetitiveness, thus making the use of manuals obsolete.