Lesson Overview
Lesson 01 framed the planner's problem: a commander has requirements, and a small force scattered across uncertain ground must meet them with a handful of lawful bearers. This lesson is where you answer that problem with a design. An architecture is not a list of radios; it is a deliberate arrangement of complementary bearers, chosen so that they carry different kinds of traffic, reach different distances, and, above all, fail in different ways. The planner who buys the most equipment has not designed anything. The planner who layers a few bearers so that no single cause can silence the whole force has.
The design rests on three ideas that run through the lesson. The first is layering: high-frequency radio for long range with no infrastructure, line-of-sight voice for local work, an off-grid mesh for text and position, and the Team Awareness Kit over the internet for the shared map, each doing what it does best. The second is force-level PACE: applying Primary, Alternate, Contingency, and Emergency not to one net but to every critical link across the force, so that each link has an ordered fall-back and the bearers behind those lines are chosen to fail independently. The third is the common operating picture: the shared map that ties the force together is powerful, but it sits on top of the bearers beneath it, and when data dies, clean voice procedure is the bedrock the force never drops below.
This is the knowledge layer. Reading will teach you how to lay out an architecture, how to drive force-level PACE so a single fault cannot cascade, and how to keep the common operating picture honest about what it depends on; but a design only proves itself when it is built, issued, and rehearsed, when a bearer is deliberately failed and the force keeps talking. That rehearsal, and any live transmitting, is done in person and on airsoft milsim exercises, with radio actually transmitted only by licensed members on amateur bands or by anyone on licence-free, low-power sets. By the end you will be able to describe the four working bearers and the role each plays in a layered architecture, explain how they fail differently and why that matters, apply PACE at force level so every critical link has an independent ordered fall-back, lay out a common operating picture that degrades gracefully onto voice when data fails, and sketch an architecture for a small force from a commander's stated requirements.
Key Terms
- Communications architecture: the overall design of how a whole force will talk, the bearers it uses, how they are layered, which links ride which bearers, and how the picture is held together; the planner's product.
- Bearer: the physical means that actually carries a message, such as HF radio, VHF or UHF voice, the Meshtastic mesh, mobile data, or the internet.
- Layering: combining complementary bearers so that each does what it does best and, crucially, so they fail for different reasons, so no single cause silences the force.
- HF (high frequency): radio in the 3 to 30 MHz range that can refract off the ionosphere to reach far beyond line of sight with no infrastructure at all.
- VHF / UHF voice: line-of-sight radio above 50 MHz for local work, used radio to radio (simplex) or extended through a repeater.
- Repeater: a fixed station on high ground that receives and rebroadcasts, extending the range of line-of-sight voice across a wide area.
- Meshtastic / LoRa mesh: long-range, low-power radios on licence-free ISM bands that relay for one another with no infrastructure, carrying tiny amounts of text and position off-grid.
- TAK (Team Awareness Kit): the application family (ATAK, WinTAK, iTAK, WebTAK) that shows a shared map of positions, markers, routes, and chat, exchanged using the Cursor-on-Target protocol.
- Common operating picture (COP): the single shared map of the force, held by TAK, that lets everyone see the same positions and markers at once.
- PACE plan: an ordered list of communications means for a link, Primary, Alternate, Contingency, Emergency, so everyone knows what to fall back to when one means fails.
- Force-level PACE: PACE applied across every critical link of the whole force at once, with the bearers chosen so that one fault cannot break two lines.
- Graceful degradation: a design that loses capability in steps as bearers fail, rather than collapsing all at once.
- PLI (position location information): a station's own position, reported automatically to the shared map.
- GeoChat: the text chat carried within TAK, tied to the map.
- Independence: the property that two bearers, or two PACE lines, fail for different reasons, so a single cause cannot take both.
The four working bearers and what each is for
A small force does not need many bearers; it needs the right few, each understood for what it does and, more importantly, for how it fails. Four working bearers, used together, cover the realistic range of a humanitarian home-defence force, and the planner should be able to recite the role and the failure mode of each without hesitation.
HF radio is the long-range floor. In the 3 to 30 MHz range it can refract off the ionosphere and reach hundreds of kilometres, behind terrain and well beyond line of sight, with no repeater, no mast, and no internet, nothing but two stations and their antennas. That independence from infrastructure is its whole value: when everything built by other people is gone, HF still reaches. Its price is that it is slow to set up well, sensitive to antenna and to the time of day, and demands skill and patience to work reliably. It is the bearer the force keeps for the case where distance is large and infrastructure is absent.
VHF and UHF voice is the local workhorse. Above 50 MHz it is essentially line of sight, radio to radio in simplex, or reaching across a wide area through a repeater on high ground. It is fast, simple, and familiar, the bearer most members will actually key most of the time. It fails when terrain blocks the path or when the repeater it leans on goes down, and the answer is height and position far more than power. It carries the routine voice traffic of a task and serves as the bearer onto which the force falls back when richer data bearers fail.
The Meshtastic mesh is the off-grid data floor. Low-power LoRa radios on licence-free ISM bands relay for each other with no infrastructure, building a small self-healing network that carries tiny messages, a few words of text and a position report, across ground where nothing else reaches. Its strength is that it needs nobody's mast and very little power; its limit is bandwidth, which is minute, so it carries only the lightest traffic. It is the bearer that keeps a thread of text and position alive when both voice and internet are gone.
TAK over the internet or mobile data is the picture bearer. The Team Awareness Kit shows a shared map of positions, markers, routes, and chat, exchanged using the Cursor-on-Target protocol and tied together, for anything beyond the local area, by a TAK server. The Royal Kaharagian Army runs its own self-hosted OpenTAKServer at tak.kaharagia.org, with per-user certificates. This is the richest bearer the force has, the one that gives the commander a live common operating picture; and it is also the most dependent, needing the internet or a mobile network to do its full work. It is the bearer the force prizes when infrastructure is present and must never assume when it is not. Cellular and the open internet sit alongside it as the underlying connectivity that TAK and ordinary messaging ride on where it is available.
LAYERED BEARER ARCHITECTURE · small force
REACH / role BEARER FAILS WHEN...
------------------------ ------------------- ------------------
long range, no infra >> HF radio >> skill / antenna /
(the distance floor) (3-30 MHz, skip) propagation poor
local voice work >> VHF / UHF voice >> terrain blocks LoS
(the daily workhorse) (simplex/repeater) or repeater down
off-grid text + posn >> Meshtastic mesh >> too much traffic
(the data floor) (LoRa, ISM, relay) (bandwidth tiny)
the shared picture >> TAK over net/data >> internet / mobile
(common op. picture) (CoT, OpenTAKSrv) network is down
|
rides on |
v
underlying carriage >> cellular / internet >> congested / cut
Rule: each bearer does ONE job well and fails for a DIFFERENT reason.
The two "floors" (HF, mesh) need no one else's infrastructure.
Layering: designing for different failure modes
The reason to hold several bearers is not redundancy for its own sake. It is that bearers which fail for the same reason are not redundant at all. Two mobile data SIMs on two carriers feel like backup until the building they both serve loses power, and then both die at once for the same cause. The discipline of layering is to lay the bearers side by side and ask, for each pair, "what one event takes them both out?" Where the honest answer is "the same event", you do not yet have a layered architecture; you have one bearer wearing two coats.
A good architecture spreads its dependence. TAK leans on the internet, so its honest backup cannot also lean on the internet; it must be a radio wave, VHF voice or HF, that does not care whether a mast has power. VHF voice through a repeater leans on that repeater, so its backup cannot be the same repeater on a second channel; it must be VHF simplex that needs no repeater, or a bearer entirely independent of fixed sites. The mesh and HF are the prized bearers precisely because they lean on nobody: the mesh relays through its own nodes, and HF needs only two stations and the ionosphere. They are slow and thin, but they are the floor the force never drops below, because the failures that flatten everything else, lost power, lost masts, lost internet, do not reach them in the same way.
This is the test you apply to the whole design at once, not link by link only. Lay out every critical link, write the bearers behind each, and trace the shared dependencies across the force. If a single power failure, a single mast, or a single internet outage appears under more than one link, that is a common failure point, and the design must move one of those links onto a bearer that does not share it. The aim is that the events which could silence the force are several and unlikely to happen together, never one and waiting.
Force-level PACE: every link an ordered fall-back
PACE, Primary, Alternate, Contingency, Emergency, was taught at net level in the operator and NCO courses as an ordered list of means for one link. At force level the planner applies the same discipline across every critical link of the whole force at once, and adds a constraint that only shows up when you see the links together: the bearers must be arranged so that one fault does not break the same PACE line on many links simultaneously.
Two principles carry over unchanged. Independence: each PACE line should fail for a different reason than the line above it, so a single fault cannot take out two lines at once. Descent: each line should ask less of the world than the one above, so that Primary can be rich and convenient while Emergency is allowed to be slow, plain, and minimal, as long as it gets through. What is new at force level is the cross-link view. If the force has six links and Primary on all six is TAK over mobile data, then a single mobile outage does not just demote one link; it knocks the Primary out from under the entire force in one stroke. The planner reads the matrix down the columns as well as across the rows, asking "if this whole column fails at once, where does the force stand?", and arranges the bearers so that no single event empties a column the force cannot afford to lose.
A force-level PACE matrix lays the links across the top and the four lines down the side, with the bearer for each cell chosen so that the rows descend and the columns spread their dependence. Worked through with the bearers the RKA actually fields, it reads naturally: TAK over the net is the Primary picture, VHF voice the Alternate that survives a lost network, simplex or HF the Contingency that needs no fixed site, and a mesh text or a runner the Emergency that asks for almost nothing.
FORCE-LEVEL PACE MATRIX · read across (per link) AND down (per line)
| HQ <-> det A | HQ <-> det B | det <-> fwd team
-------------+----------------+----------------+------------------
P Primary | TAK / net data | TAK / net data | VHF simplex
-- fails together if the NETWORK drops (whole P row) --
-------------+----------------+----------------+------------------
A Alternate| VHF via | VHF via | hand / whistle
| repeater | repeater | (in sight)
-- different bearer (radio wave), survives lost network --
-------------+----------------+----------------+------------------
C Conting. | VHF simplex / | HF radio | VHF simplex
| HF radio | |
-- no fixed site needed; survives lost repeater --
-------------+----------------+----------------+------------------
E Emergency| Mesh text; | Mesh text; | mesh text /
| else runner | else runner | re-join
-- asks almost nothing; the floor under the force --
Column test: if a whole ROW fails at once, can the force still talk
on the row below? Here yes: lose the net (P) and the force is on
radio (A); lose repeaters (A) and it is on simplex/HF (C); lose
those and a thread of text/position survives on the mesh (E).
The value of seeing it as a matrix is that the planner catches the cascade before it happens. A net-level PACE plan can be perfect for its own link and still be dangerous if every link copied it, because then the whole force shares one Primary and falls together. Designing PACE at force level means staggering the bearers across links where it helps, so that the events which demote one link do not demote them all, and so that the force degrades in steps rather than going dark in one.
The common operating picture, and what holds it up
The common operating picture is the prize of a modern small force. With TAK and the OpenTAKServer at tak.kaharagia.org, every connected member sees one map: who is where, what has been marked, which routes are planned, and a chat thread tied to the ground. It collapses a dozen voice reports into a glance, and it is the single most useful thing the architecture produces when it is working. It is also the most misunderstood, because its richness hides how much it depends on the bearers beneath it.
The picture is not a bearer; it is a layer that rides on bearers. TAK exchanges Cursor-on-Target messages, and those messages have to travel on something: the internet or mobile data for the full live picture, or, in stripped-down form, the Meshtastic mesh through a TAK-to-mesh gateway that forwards only the lightest traffic, position reports and GeoChat, because the mesh's bandwidth is tiny. When the internet is up, the picture is full and immediate. When it falls back to the mesh, the picture survives but thins to little more than dots moving and short text. And when both are gone, the picture does not exist at all, and the force is back to describing positions in words over the radio. The planner must design the picture knowing this descent, and must never let the force grow so used to the map that it cannot work without it.
This is why voice remains the bedrock. The cleanest architecture in the world degrades, under enough failure, to a national speaking a grid and a sighting report over VHF in plain, disciplined voice procedure, and that national must be able to do it without the map to lean on. The common operating picture is built on top of communications; it does not replace them, and the data tools assist voice rather than removing the need for it. A force that can hold its picture in words when the screens go dark has a resilient architecture. A force that goes silent the moment the map disappears has built a tower with no foundation. The design rule follows directly: the picture is the top layer, the bearers are the structure, and clean voice is the ground the whole thing stands on.
THE PICTURE DEPENDS ON THE BEARERS BENEATH IT
[ Common Operating Picture: the shared TAK map ] <- the prize
| | |
rides on internet rides on mesh cannot ride on...
(full picture) (thin: PLI + ...nothing; falls to
| GeoChat only) |
v v v
+---------------------+ +-------------+ +-----------------------+
| net up: positions, | | net down, | | data all gone: |
| markers, routes, | | mesh up: | | VOICE PROCEDURE |
| full chat | | dots + text | | grid + report in |
+---------------------+ +-------------+ | clean plain voice |
FULL DEGRADED +-----------------------+
BEDROCK
Graceful degradation: full -> thin -> voice. The force must be able
to work at EVERY step, and must train to work at the last one.
In Practice: Captain Okonkwo designs the architecture for a flood-relief task
Captain Okonkwo, OF-2 and the communications planner for a flood-relief task in support of the civil authorities, starts not with a catalogue of radios but with the commander's requirements: a task headquarters must keep a live picture of two detachments working separated areas, each detachment must talk within itself, and the headquarters must be reachable even if the local networks fail under the disaster, which is exactly the condition the task exists for. From those requirements she designs an architecture rather than a shopping list.
She lays the four bearers out by role. TAK over mobile data gives the headquarters its common operating picture of both detachments while the networks hold, riding on tak.kaharagia.org. VHF voice, through a repeater on high ground where one is reachable and simplex where it is not, carries the routine voice traffic and is her first independent fall-back, because a radio wave does not care whether a flooded exchange has lost power. For the off-grid floor she seeds Meshtastic nodes through both detachments, so that even if every network in the area is down, position reports and short text still relay across the ground and a thinned version of the picture survives. And because the task could outlast the local infrastructure entirely, she keeps an HF link from the headquarters as the long-range floor that needs nobody's mast.
Then she draws the force-level PACE matrix and reads it down the columns. Primary across the picture links is TAK over the net, and she notes at once that a single network failure, likely in a flood, would empty that whole row; so she makes sure the Alternate row beneath it, VHF voice, is genuinely independent, leaning on radio and a repeater rather than on the network, and the Contingency row beneath that, simplex and HF, leans on no fixed site at all. The Emergency row is a mesh text, with a physical runner where the water still allows it. The columns now spread their dependence: lose the network and the force drops to voice, lose the repeaters and it drops to simplex and HF, and a thread of text and position survives on the mesh below even that.
Finally she pressure-tests the picture. She tells her detachment commanders plainly that the live map is a gift, not a guarantee, and she has them rehearse the degraded case on the exercise that precedes the task: the screens are switched off, and each detachment passes its position and a short situation report by clean VHF voice procedure alone, a grid and a SALUTE-style sighting in plain, disciplined words. They are slow the first time and sharp by the third. Her licensing strategy keeps it lawful, with the amateur HF and repeater work done by her licensed members and the licence-free sets and the mesh open to the rest, and she writes the whole design into the signals annex of orders, which Lesson 10 will govern. The architecture is layered, it degrades in steps, and the force can still talk when the map goes dark.
Check Your Understanding
A fellow planner proposes a two-line force PACE where Primary is TAK over mobile data on carrier one and Alternate is TAK over mobile data on carrier two. Using the principles of independence and force-level (column) thinking, explain why this is a weak architecture and propose a stronger Alternate and Contingency from the bearers the RKA fields.
Name the four working bearers in a small-force architecture, and for each give in one line the job it does best and the reason it fails. Then say which two are the "floors" that need no one else's infrastructure, and why that matters.
Explain why the common operating picture is described as a layer that "rides on" bearers rather than as a bearer itself. Describe how the picture degrades as the internet and then the mesh are lost, and state what the force falls back to at the bottom of that descent.
Reflection (write a short paragraph): Think about how dependent a team you know, military or civilian, has become on a single rich tool, such as a shared map, a messaging app, or a network. If that tool vanished tomorrow, could the team still do its work in a slower, plainer way, or has the convenience quietly become a single point of failure? What would it take to make the team able to degrade gracefully instead of going dark?
Summary
- A communications architecture is a deliberate arrangement of complementary bearers, designed so they carry different traffic, reach different distances, and above all fail for different reasons, never a list of radios bought for its own sake.
- The four working bearers of a small force are HF (long range, no infrastructure), VHF/UHF voice (local workhorse, simplex or repeater), the Meshtastic/LoRa mesh (off-grid text and position), and TAK over the internet or mobile data (the common operating picture via the RKA's OpenTAKServer at
tak.kaharagia.org), with cellular and the internet as the underlying carriage. - Layering means spreading dependence: lay the bearers side by side and remove any case where one event silences two, so the floors that need no one else's infrastructure, HF and the mesh, are the level the force never drops below.
- Force-level PACE applies Primary, Alternate, Contingency, Emergency across every critical link at once and is read down the columns as well as across the rows, so a single fault does not empty a whole line under the entire force; the bearers are staggered so the force degrades in steps rather than going dark at once.
- The common operating picture is a layer that rides on bearers, not a bearer itself: full over the internet, thinned to position and short text over the mesh, and gone when both fail, at which point clean voice procedure is the bedrock the force works on without the map.
- Builds on Lesson 01 (From Section to Force) and the operator and NCO courses (SIG 201, SIG 220, SIG 310); the spectrum and licensing strategy behind the bearers is Lesson 03; resilience and graceful degradation are deepened in Lesson 04 and HCR 220 (Emergency Preparedness); the design is written into the signals annex of orders in Lesson 10 and PME 210 (Basic Staff Duties and Written Orders).
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