Royal Army College

Lesson Overview

Two operators with identical radios and full batteries can have completely different results: one gets through cleanly, the other cannot raise the net, and the difference is very often not the set but the antenna and where they are standing. The antenna is where the signal actually leaves and enters the radio, and how the radio waves then travel, what carries them and what blocks them, decides whether a message arrives. This is the realm of antennas, siting, and propagation, and for the operator it is among the most useful knowledge there is, because it is the lever that most often turns a failed link into a good one, frequently at no cost but moving a few metres or raising the antenna a little. An operator who understands it can get through where one who does not simply gives up.

The reason this matters so much is that, for the kinds of radio the Army uses most, height and a clear path beat power. A handheld on low power from a hilltop with a clear view will usually outreach the same handheld on high power from a valley or inside a building, because the signal travels best in something close to a straight line and is blocked or absorbed by ground, hills, buildings, and dense woods. So the operator's biggest single lever on range is not the power switch but where they put themselves and their antenna: high, clear, and with as straight a path to the other station as the ground allows. Understanding this turns "I can't get through" from a dead end into a problem the operator can often solve by thinking about the path the signal must travel and improving it.

This is the knowledge layer. It teaches you how radio waves travel, why height and a clear path matter so much, the basics of the antenna, and how to site yourself and your antenna for a better signal, so that you understand the link between the set and the far station. The real skill of reading the ground for communications, siting an antenna, and rigging a field antenna is built hands-on under a qualified signaller and certified in person, and the deeper antenna theory belongs to the NCO signals course; this is the operator's working understanding. Read this to know how the signal travels; learn to site and rig in person.

By the end you will be able to explain how radio waves travel and why height and a clear path matter most, describe the basics of the antenna and how to keep it working, site yourself and your antenna to improve a signal, work around terrain and obstacles that block the signal, and recognise and fix the common ways an operator weakens their own signal.

Key Terms

Antenna: the part of the radio that radiates the transmitted signal into the air and captures the received one; where the signal enters and leaves the set.
Propagation: the way radio waves travel from one antenna to another, and what helps or hinders them, which decides whether a message gets through.
Line of sight: the roughly straight path a VHF or UHF signal travels best along; the more nearly the two antennas can "see" each other, the better the link.
VHF/UHF: the very high and ultra high frequency bands the Army's handhelds use, which travel mainly by line of sight and are blocked by terrain and buildings.
Height: the single biggest lever on line-of-sight range; the higher the antenna, the further it can reach over obstacles and the horizon.
Obstruction: anything in the signal's path, hill, building, dense wood, that blocks or weakens a line-of-sight signal.
Dead spot: a location where the signal cannot get through, often behind an obstruction, escapable by moving a short distance.
Siting: the operator's choice of where to stand and place the antenna to give the signal the best path to the far station.
Field antenna: an antenna improvised or rigged in the field, or the set's own antenna raised, to improve range beyond the basic handheld whip.
Relay: passing a message through a third station that can reach both ends, when the two ends cannot reach each other directly (related to the repeater of Lesson 05).

How radio waves travel

To site a radio well you need a working picture of how its waves travel, and for the VHF and UHF bands the Army's handhelds use, that picture is simple and powerful: these signals travel best in a roughly straight line, close to line of sight, and are blocked or weakened by solid things in the way. They do not bend far over hills or around buildings or far through the earth; broadly, if the two antennas could "see" each other, the signal gets through well, and the more the view between them is blocked by ground, hills, buildings, or dense woods, the weaker the link becomes, until behind a big enough obstruction it fails entirely. This line-of-sight behaviour is the single most useful fact an operator can hold about propagation, because everything about siting follows from it.

From line of sight comes the dominance of height. Because the signal travels in near-straight lines and the earth curves and is cluttered with obstacles, raising an antenna higher lets it "see" further, over the horizon and over obstructions, which is why height is the biggest single lever on range. The same handheld reaches dramatically further from a hilltop than from a hollow, not because anything in the set changed, but because from the height the signal has a clear path to far more places. This is why signallers and antennas are got up high wherever possible, and why the repeater of Lesson 05, a set placed high and well-sited, can link radios that could never reach each other directly: it borrows height to gain line of sight.

The practical consequence, worth stating plainly because it surprises people, is that for these bands, height and a clear path usually beat power. Turning up the power helps a little, but it cannot make a signal go through a hill; moving to where the signal has a clear path can do what no amount of power will. So the operator who cannot get through thinks first not "more power" but "better path", higher, clearer, around the obstruction, which is the operator's real toolkit for range and the subject of the rest of this lesson.

   HOW VHF/UHF SIGNALS TRAVEL  (line of sight)

   GOOD:  antenna --------- clear path --------- antenna   (they "see"
          (high)                                  (high)    each other)

   BAD:        antenna ---X[ HILL ]X--- antenna             (blocked:
              (in a hollow)                                  weak or dead)

   HEIGHT lets the antenna see OVER the horizon and obstacles -> the
   biggest lever on range.  A repeater (Lesson 05) borrows height.

   For these bands: HEIGHT and a CLEAR PATH usually beat POWER.
   "Can't get through" -> think "better PATH", not just "more power".

The antenna and keeping it working

The antenna is where the signal leaves and enters the set, and a few plain facts about it make a real difference to the operator. First and most basic: the antenna must be connected and sound, because a set transmitted with a loose, damaged, or missing antenna reaches almost nothing and can be damaged itself, and a broken or loose antenna connection is one of the commonest causes of a set that mysteriously half-works, as the last lesson warned. The operator checks the antenna is firm and intact as part of setting up.

Second, orientation matters. The Army's nets are generally worked with the antenna held vertical, and a signal radiates best to other vertical antennas, so holding the antenna upright rather than slanted or horizontal keeps the link strong. An operator who lets the antenna flop sideways, or transmits with the set flat, weakens their own signal for no reason.

Third, the antenna wants to be clear and high. The handheld's own short antenna works far better held up and away from obstructions than pressed against the body, buried in a pack, or held low, for reasons the next section develops. And where more range is needed than the handheld's whip can give, a field antenna, the set's antenna raised on a mast or pole, or a simple rigged antenna got up high, can extend range markedly; the operator should know that raising or improving the antenna is a real option when the basic whip will not reach, even if the detailed rigging of field antennas is a skill built in person and deepened in the NCO signals course. The operator's working rule is simple: a good antenna, sound, vertical, clear, and as high as possible, is worth more than almost anything else they can do for their range.

Siting: where you stand decides whether you get through

Because height and a clear path dominate, siting, where the operator chooses to stand and place the antenna, is the operator's single most powerful tool for getting through, and it is free. The principles are few and follow directly from line of sight.

Get high. Move to higher ground where you can, because height buys line of sight over obstacles and the horizon. A hilltop, a rise, an upper floor, even standing up rather than crouching, can transform a link. The operator who needs range looks first for height.

Get clear. Put as little as possible between your antenna and the far station: clear of hills, buildings, and dense woods, and out into the open rather than tucked behind an obstruction. Where you cannot avoid an obstacle, get to the side of it that faces the far station, so the bulk of it is not in the path. Even small obstructions close to the antenna, a wall, a vehicle, a thick tree, matter, so step clear of them.

Move to escape a dead spot. A dead spot, a place where the signal simply will not get through, is usually the shadow of an obstruction, and the cure is often to move only a short distance, a few metres, around a corner, onto a slight rise, until the path opens. The operator who cannot get through does not give up where they stand; they move, deliberately, to improve the path, because a link that is dead in one spot is frequently fine a few steps away.

Hold the antenna well. Keep the antenna vertical, up, and clear of your body and metal, because the human body and nearby metal absorb and block the signal badly: an antenna pressed against the chest or held low radiates a fraction of what the same antenna held up and out does. Simply raising the handheld and holding the antenna clear can be the difference between a broken and a clean link. These are the cheapest gains in radio, available to every operator at every moment, and the disciplined operator takes them by habit.

   SITING FOR A SIGNAL  (free range, by improving the path)

   GET HIGH          higher ground, upper floor, even standing up;
                     height buys line of sight
   GET CLEAR         out of the shadow of hills/buildings/woods; to the
                     side of an obstacle that faces the far station
   ESCAPE DEAD SPOTS move a few metres / around a corner / onto a rise;
                     don't give up where you stand
   HOLD THE ANTENNA  vertical, up, and CLEAR of your body and metal
                     (the body absorbs the signal badly)

   The cheapest range there is: it costs only thought and a few steps.

Terrain, obstacles, and working around them

The ground itself is the operator's main adversary in propagation, because terrain and what stands on it is what blocks line of sight. Hills and high ground cast radio shadows behind them; a station in a valley or behind a ridge may be unable to reach over it, while the same station on the crest reaches for miles. Buildings and urban clutter block and reflect signals, so in built-up areas links are short and patchy and siting matters even more. Dense woods and vegetation absorb and weaken signals, more so when wet, so a net that works in the open may struggle deep in a forest. And distance itself, combined with the earth's curvature, sets a limit on line of sight that only height extends. The operator reads the ground for its effect on the signal just as they read it for movement, asking where the path to the far station is clear and where it is blocked.

When terrain blocks a direct link, the operator has options beyond giving up. The first, always, is to improve the path: get higher or clearer, as above, until line of sight is restored. The second is to relay: pass the message through a third station that can reach both ends when the two ends cannot reach each other directly, a person doing what the repeater of Lesson 05 does automatically. If the section's two ends cannot hear each other across a ridge but both can hear a station on the high ground between, that station relays, and the message gets through. The third, where the net is built for it, is the repeater itself, which the operator uses by knowing the local repeaters, as Lesson 05 taught, while always keeping a simplex fallback. The point is that a blocked link is a problem to be worked, by height, by moving, by relay, or by repeater, not a flat impossibility, and the operator who understands propagation has these tools where the one who does not simply reports "no comms" and stops.

In Practice: Getting Through from the Wrong Place

A section signaller of the Royal Kaharagian Army needs to pass an important report, and from where he stands, in a wooded hollow behind a ridge, he cannot raise the net. A weak operator turns the power to maximum, tries a few more times, and reports "no comms". The College's signaller understands propagation and works the problem.

He reasons about the path, not the power: his handheld is on VHF, which travels by line of sight, and he is in the worst possible place for it, low, in dense wet woods, with a ridge between him and the far station, so the signal is blocked and absorbed exactly as he would expect. More power will not push a signal through a hill. So he improves the path. He moves, deliberately, out of the trees and up onto the rise at the edge of the hollow, gaining height and getting clear of the worst of the wood and to the side of the ridge that faces the far station. He holds his antenna vertical, up, and clear of his body, not pressed against his chest as he had been. From the new spot, with a far better path, the link comes up cleanly, and he passes his report by the voice procedure of Lesson 02, no extra power needed.

Where even the rise had not been enough, he had a next step ready: relay the message through a section member he knew was on the high ground between, who could reach both him and the far station, doing by hand what a repeater does automatically. The report got through, not because his set was special or his power high, but because he treated "no comms" as a path problem he could solve, used height and clearance and the free gain of holding the antenna well, and kept relay in reserve. That is the operator's real power over range: not the power switch, but the understanding of how the signal travels and the willingness to move and think to give it a clear path. The set and battery of the last lesson were ready; the propagation sense of this one got the message home.

Check Your Understanding

Explain how VHF and UHF signals travel (line of sight), why height is the biggest lever on range, and why, for these bands, "height and a clear path usually beat power." How should this change what an operator does first when they cannot get through?
Set out the basics of the antenna that matter to an operator (connected and sound, held vertical, kept clear and high, and the option of a field antenna), and why a loose antenna and an antenna held against the body each weaken the signal.
State the principles of siting (get high, get clear, escape dead spots by moving, hold the antenna well), and describe how terrain and obstacles block a signal and the operator's options when a direct link is blocked (improve the path, relay, repeater).

Reflection (write a short paragraph): This lesson says the operator's biggest lever on range is not the power switch but where they put themselves and their antenna, and that "no comms" is usually a path problem that can be solved by moving and thinking. Why might an inexperienced operator reach for more power and then give up, while an experienced one moves a few metres and gets through? Picture yourself unable to raise the net on an important message: walk through, in your own words, what you would check and try, in order, and explain why understanding how the signal travels turns a dead end into a problem you can work.

Summary

The antenna and siting, not just the set, often decide whether a message gets through: two identical radios can give opposite results from different places. Understanding propagation is the operator's most useful lever on range, and it is mostly free.
The Army's handhelds use VHF/UHF, which travel by line of sight and are blocked or absorbed by terrain, buildings, and dense woods. Height is the biggest lever on range, because it buys line of sight over obstacles and the horizon, and for these bands height and a clear path usually beat power.
The antenna must be connected and sound (a loose antenna is a common half-failure), held vertical (to match the net's vertical antennas), and kept clear and high; a field antenna or a raised antenna extends range when the whip will not reach.
Siting is the operator's most powerful free tool: get high, get clear of obstructions, escape dead spots by moving a short distance, and hold the antenna vertical, up, and clear of the body and metal (the body absorbs the signal badly).
Terrain is the main adversary: hills cast radio shadows, buildings and woods block and absorb, distance and the earth's curve limit line of sight. A blocked link is worked, not abandoned, by improving the path, by relay through a third station, or by a repeater.
This is the knowledge layer; reading the ground for communications and rigging field antennas are built hands-on under a qualified signaller and certified in person, with deeper antenna theory in the NCO signals course (SIG 310). This lesson builds on the set of Lesson 06, uses the simplex/repeater and PACE thinking of Lessons 05 and 10, and feeds the troubleshooting of Lesson 08.

Antennas, Siting, and Propagation