Royal Army College

Lesson Overview

The radio is not only a tool the Army uses; it is a battleground in its own right, because the act of transmitting puts energy into the air that an adversary can detect, locate, and attack. The contest over the use of the electromagnetic spectrum is electronic warfare, and for the operator it presents three distinct dangers: that the enemy listens to your transmissions (interception, the threat the earlier lessons mostly addressed), that the enemy locates you by them (direction-finding), and that the enemy attacks your ability to communicate (jamming and interference). This lesson takes the second and third of these in depth, the threats of being found and being jammed, and the discipline and drills that counter them. It is written defensively, as everything in this course is: the Royal Kaharagian Army's concern is to recognise and survive electronic warfare directed at it, not to conduct offensive electronic attack.

Two ideas govern the lesson. The first is that every transmission is a beacon: the moment you press to talk, you radiate energy that can be detected and direction-found, so transmitting reveals not only what you say and the pattern of your saying it, but where you are. This makes emission control (Lesson 02) a survival measure, not just a security one, and it means the operator who transmits long, often, and on high power is lighting a beacon for the enemy to find and strike. The second is that jamming is meant to make you stop, and the counter is not to stop but to work through it: a jammed operator who falls silent has given the enemy exactly what the jamming was for, while a trained one recognises the jamming, reports it without revealing its effect, and keeps communicating by the anti-jamming drills. Being found and being jammed are dangers to be managed by discipline and drill, not panicked over.

This is the knowledge layer. It teaches you the electronic-warfare threats of direction-finding, jamming, and interference, and the defensive measures and drills that counter them, so that you understand how the spectrum is contested and how to survive it. The actual recognition of jamming under real conditions and the practised anti-jamming and emission-control drills are built on exercises under qualified supervision and certified in person. Read this to know the threat and the counters; the drills are built in the doing.

By the end you will be able to explain electronic warfare and the operator's three dangers, describe how direction-finding locates you and the measures that reduce the risk, recognise jamming and distinguish it from natural interference, apply the anti-jamming drill of recognise, report, and work through, and explain why the Army's posture is defensive.

Key Terms

Electronic warfare (EW): the contest over the use of the electromagnetic spectrum, including listening to, locating, and attacking communications, and defending against the same.
Direction-finding (DF): locating a transmitter by detecting the direction its signal comes from, usually from several places at once, to fix its position.
Emission control (EMCON): the disciplined limiting of transmissions to reduce what an enemy can intercept, analyse, and direction-find (Lesson 02), here a survival measure.
Jamming: deliberate transmission of interfering energy to deny or degrade an enemy's communications by drowning out their signals.
Interference: disruption of a signal, which may be natural or unintentional, or deliberate (jamming); the operator must distinguish the two.
Meaconing and deception: deliberate false or misleading transmissions intended to confuse, mislead, or intrude on a net (related to the intrusion of Lesson 03).
Anti-jamming drill: the trained response to jamming, to recognise it, report it without revealing its effect, and work through by procedure rather than falling silent.
Working through: continuing to communicate despite jamming, by changing frequency, improving the link, or using procedure, rather than stopping.
Burst and brevity: keeping transmissions as short as possible so there is less time to detect, direction-find, and jam them.
Defensive posture: the principle that the Army recognises and counters EW directed at it, and does not conduct offensive electronic attack.

Electronic warfare and the operator's three dangers

Electronic warfare is the military contest over the electromagnetic spectrum, the airwaves the radio uses, and from the operator's point of view it reduces to three dangers that flow from a single fact: transmitting radiates energy an adversary can exploit. The first danger is interception, that the enemy listens to your transmissions, reading the content if they can and analysing the pattern if they cannot, which is the threat the bulk of this course has addressed through brevity, authentication, security without encryption, and traffic discipline. The second is direction-finding, that the enemy uses your transmissions to locate you physically, which this lesson takes up next. The third is electronic attack, chiefly jamming, that the enemy transmits interfering energy to deny or degrade your communications, which this lesson takes up after.

All three flow from the same source, so the same root discipline reduces all three: emission control, transmitting as little as possible, as briefly as possible, on no more power than needed. The earlier lessons taught EMCON as a security measure, to give the enemy less to intercept and analyse; this lesson adds that it is equally a survival measure, because the same transmissions that can be intercepted can be direction-found and jammed, and the operator who minimises their emissions reduces all three dangers at once. The disciplined, quiet operator is harder to read, harder to find, and harder to jam; the chatty, long-winded, high-power operator is easier on all three counts. Emission control is thus the foundation of the operator's electronic-warfare survival, as it was of their security.

The lesson's defensive framing matters here and is stated plainly: the Royal Kaharagian Army, a small, lawful, humanitarian force, concerns itself with recognising and surviving electronic warfare directed against it, not with conducting offensive electronic attack. The operator learns these threats to defend against them, the same way they learn the threats of interception to guard their messages. What follows is defence: how not to be found, and how to keep communicating when jammed.

Direction-finding: the transmission that locates you

Direction-finding is the locating of a transmitter by detecting the direction its signal arrives from, and when two or more direction-finders take a bearing on the same transmission from different places, their bearings cross at the transmitter's position, fixing it. The operator must grasp the consequence plainly: to transmit is to risk revealing where you are. Every transmission is a beacon that a capable adversary can take a bearing on, and the more and the longer you transmit, the more chances they have to fix you, and the more accurately. For a small force, being located can be as dangerous as being overheard, because a fixed position can be avoided, watched, or struck.

Because direction-finding feeds on transmissions, the measures against it are measures of emission discipline and movement. Transmit as little and as briefly as possible, because a short transmission gives the direction-finder little time to take a bearing, which is one more reason for the brevity the whole course preaches; long transmissions are gifts to a direction-finder. Use the lowest power that does the job, because lower power is harder to detect and bear at a distance, as the set lesson of SIG 201 taught. Move, so that even if a transmission is fixed, you are no longer there: a station that transmits and then moves denies the enemy the link between the fix and the present position, while one that transmits repeatedly from the same place hands them a confirmed, current location. And use terrain, since the same ground that blocks a signal from reaching a friendly station can also shield it from an enemy direction-finder; transmitting from cover and avoiding silhouetting your signal from high, exposed ground reduces how far and how clearly it carries to a hostile receiver.

The discipline against direction-finding, then, is brevity, low power, movement, and terrain, the same emission control that serves security, now serving survival. The operator who treats every transmission as a beacon that could call down attention, and who is short, quiet, mobile, and covered, is far harder to find than one who transmits long, loud, often, and from the same exposed spot. Being found is not inevitable; it is, largely, a consequence of emission indiscipline that discipline prevents.

   DIRECTION-FINDING: TO TRANSMIT IS TO RISK BEING FOUND

   HOW IT WORKS   2+ direction-finders take bearings on your signal ->
                  bearings cross -> your POSITION is fixed
                  (more/longer transmissions = more, better fixes)

   COUNTER (emission discipline + movement):
     BREVITY        short transmissions give little time for a bearing
     LOW POWER      harder to detect and bear at a distance
     MOVE           transmit then move, so the fix is no longer where you are
     TERRAIN        transmit from cover; don't silhouette your signal from
                    high exposed ground

   Every transmission is a BEACON. Short, quiet, mobile, covered = hard
   to find. Long, loud, repeated, exposed = a confirmed location.

Jamming and interference

Jamming is the deliberate transmission of interfering energy to deny or degrade your communications by drowning out the signals you are trying to receive, and its purpose is almost always to make you stop communicating, to break the net at a critical moment so that a force cannot coordinate. The first skill is to recognise it, and the difficulty is that jamming can resemble ordinary interference, which may be natural (atmospheric noise, terrain effects) or unintentional (another user, a fault), and the operator must not cry "jamming" at every burst of static nor dismiss real jamming as a glitch. Signs that interference may be deliberate jamming include its strength and persistence, its timing (interference that appears exactly when you most need the net is suspicious), its character (some jamming sounds like deliberate noise, tones, or recorded sounds rather than natural static), and its effect (interference that precisely blocks your frequency while others are clear). The operator suspects jamming when the interference is strong, persistent, well-timed against their activity, and not explained by natural or accidental causes, and confirms by the checks below.

A practical first discipline is to make sure the problem is really jamming and not your own set: before concluding you are jammed, run the troubleshooting of SIG 201, check the set, the antenna, the channel, the siting, because an operator who reports jamming when in fact their antenna is loose has misdiagnosed the problem. Once a genuine equipment fault is ruled out and the interference fits the picture of jamming, the operator treats it as jamming and applies the drill. The related threat of meaconing and deception, deliberate false or misleading transmissions meant to confuse or intrude on the net, is countered by the authentication and intrusion-recognition of Lesson 03; jamming attacks your ability to hear, deception attacks your ability to trust, and both are part of the electronic attack the operator must recognise.

The anti-jamming drill: recognise, report, work through

The trained response to jamming is the opposite of what the jamming intends. The jamming wants you to stop; the drill is to keep communicating, and it has three parts: recognise, report, and work through.

Recognise it as jamming, by the signs above and after ruling out a fault in your own set, so that you respond to it as the attack it is rather than struggling with it as a malfunction.

Report it, so that command knows the net is under electronic attack, which is important intelligence, but report it without revealing to the enemy that the jamming is working. This is a subtle and important point: if you announce on the air "we are being jammed, I cannot hear you," you have told the jammer their attack is succeeding, encouraging them to continue and confirming their effect. So the jamming is reported by procedure, often on a different means or in a way that does not advertise the effect, so that the enemy does not learn how well their jamming is working. The report lets your own side respond; it must not coach the enemy.

Work through it, which is the heart of the drill: do not fall silent, but keep communicating despite the jamming. Working through can mean changing to an alternate frequency by the signals plan (a jammer can only jam the frequencies it knows and covers, so a pre-arranged frequency change can escape it), improving the link by the means of SIG 201 (a better antenna, more power within limits, better siting, getting closer), using maximum brevity so the essential gets through in the gaps, or falling back through the PACE plan to another means entirely. The principle is that a jammed net is not a dead net to a trained operator, who has frequencies to move to, links to improve, and fallbacks to use, and who treats jamming as a problem to be worked exactly as a failed link is worked, rather than as a defeat. The operator who recognises, reports without revealing the effect, and works through, denies the jamming its purpose, while the one who simply stops hands the enemy the silence they were trying to impose.

   THE ANTI-JAMMING DRILL  (the jamming wants you to STOP; don't)

   RECOGNISE      confirm it's jamming, not your own set (run the SIG 201
                  troubleshooting first); judge by strength, timing,
                  character, and effect
   REPORT         tell command the net is under attack, BUT without
                  revealing on the air that the jamming is WORKING
                  ......... don't coach the enemy that their attack succeeds
   WORK THROUGH   do NOT fall silent. Change frequency by the signals plan;
                  improve the link (antenna/power/siting/closer); maximum
                  brevity through the gaps; or fall back via the PACE plan

   A jammed net is NOT a dead net to a trained operator. Stopping hands
   the enemy the silence they wanted.

In Practice: Found, and Jammed

A signals NCO of the Royal Kaharagian Army runs an exercise in which the assessors play a capable adversary with direction-finding and jamming. A weak operator transmits long and often from an exposed rise, is quickly located, and, when jammed at the critical moment, announces his distress on the air and falls silent, handing the adversary everything they wanted. The College's NCO survives both threats by discipline and drill.

Against direction-finding, he treats every transmission as a beacon. He keeps transmissions short and on the lowest power that reaches, transmits from cover rather than the exposed rise, and moves after transmitting, so that even when the adversary's direction-finders take a bearing, the fix is on a place he has already left. He gives them few, brief, low-power, covered transmissions to work with, and they cannot reliably locate him, where his careless counterpart was fixed in minutes.

When the adversary jams the net at the decisive moment, he runs the anti-jamming drill. He recognises it as jamming, not a fault, by ruling out his own set first and judging the interference strong, well-timed, and unnatural. He reports the electronic attack to command by a means that does not advertise on the air that the jamming is working, denying the adversary the confirmation they seek. And he works through: he changes to an alternate frequency by the signals plan, escaping the jammed channel the adversary was covering, and where that is also contested he falls back through the PACE plan to another means, keeping the essential traffic flowing with maximum brevity. The net is degraded but not broken, because he treated jamming as a problem to work, not a defeat to accept. The adversary neither found him reliably nor silenced him, because he met electronic warfare with emission discipline and a drilled response, which is exactly what surviving it requires.

Check Your Understanding

Explain what electronic warfare is and the operator's three dangers (interception, direction-finding, electronic attack), and why emission control is the root discipline against all three, a survival measure as much as a security one. Why is the Army's posture defensive?
Explain how direction-finding locates a transmitter and why "every transmission is a beacon," and set out the measures that reduce the risk (brevity, low power, movement, terrain).
Explain how to recognise jamming and distinguish it from natural or accidental interference (including ruling out your own set first), and set out the anti-jamming drill (recognise, report without revealing the effect, work through). Why must the report not reveal that the jamming is working, and why is "work through" the right response rather than falling silent?

Reflection (write a short paragraph): This lesson says jamming is meant to make you stop, so the trained response is not to stop but to work through it, and that announcing "I'm being jammed, I can't hear you" hands the enemy confirmation their attack is working. Why is the instinct under jamming, to broadcast your distress and then give up, exactly the wrong one, and what discipline does it take to do the opposite? Then think about direction-finding and the idea that every transmission reveals where you are: how would treating the press-to-talk as something that could call down attention change how you operate on a net?

Summary

Electronic warfare is the contest over the electromagnetic spectrum, presenting the operator three dangers because transmitting radiates exploitable energy: interception (being heard), direction-finding (being located), and electronic attack / jamming (being denied communications). Emission control is the root discipline against all three, a survival measure as much as a security one. The Army's posture is defensive: recognise and survive, do not conduct offensive attack.
Direction-finding fixes a transmitter's position by crossing bearings on its signal, so every transmission is a beacon and transmitting risks revealing where you are. Counter it with brevity, low power, movement (transmit then move), and terrain (transmit from cover, avoid exposed high ground).
Jamming is deliberate interference meant to make you stop. Recognise it by strength, timing, character, and effect, and distinguish it from natural or accidental interference, first ruling out a fault in your own set. Meaconing and deception attack trust and are countered by authentication (Lesson 03).
The anti-jamming drill is recognise, report, work through: confirm it is jamming; report the attack to command without revealing on the air that it is working (do not coach the enemy); and work through by changing frequency on the signals plan, improving the link, using maximum brevity, or falling back through the PACE plan. A jammed net is not a dead net; stopping hands the enemy the silence they wanted.
This is the knowledge layer; recognising jamming under real conditions and the practised anti-jamming and emission-control drills are built on exercises under qualified supervision and certified in person. This lesson extends the emission control of Lesson 02 and the threat picture of Lesson 01, combines with the traffic analysis of Lesson 06, uses the troubleshooting and PACE of SIG 201, and feeds the physical security of Lesson 08 and the OPSEC of Lesson 10.

Electronic Warfare: Jamming, Interference, and Direction-Finding