Tactically Relevant RF Training
A one-year plan for field radio: wire antennas and HF, networks, mesh, spectrum, drones and power. I am working through it. The blocks line up with the electrical engineering courses I am taking next.
The checklist, drill history and gate log are mine. Signed out, the page is read-only.A block is done when its gate passes, timed, outdoors.
Each block lists scored practice. Results go in the gate log: an exam percentage, a drill time, where a signal was heard.
Daily drill
20 problems across ten kinds: decibels, wavelength, dipole length, the off-centre feed point, Ohm's law, power budgets, azimuths, Zulu time, one-time pads and subnetting. The clock runs from the first problem to the last. Same problems all day. New ones tomorrow.
Rules
- Log everything. The plan is scored on the log.
- Outdoors beats the bench. One contact from a hilltop on battery is worth three from a desk.
- Every gate has a clock. If it is not timed, it is not a gate, it is a hobby.
- Teach it to keep it. A skill you cannot explain with a drawing is a skill you half have.
- Never let the arithmetic be the thing that fails. Decibels, wavelengths and subnet masks are drilled until they are reflexes.
Every week
| Study | Three hours a week from the block's reading, in sittings of at least an hour. |
|---|---|
| On the air | Two hours a week transmitting, from block two onward. Logged contacts. |
| Drills | Ten minutes a day on the drill at the top of this page: decibels, wavelengths, antenna lengths, Ohm's law, subnetting. Timed, scored, kept. |
| Field build | One outdoor exercise a month from week twelve, carrying the whole kit. Twenty four hours minimum, seventy two preferred. |
| Review | Sunday evening: read the week's log, score the drills, write the next week's three priorities. |
1. Licence and the arithmetic
Weeks 1 to 4
The licence itself is paperwork. The exam pools are the point: they force the mathematics and the regulations that every later block assumes you already have.
- Pass the amateur radio Technician and General exams in a single sitting.
- Drill until automatic: decibels to power ratios, wavelength from frequency, half-wave dipole length (468 divided by the frequency in megahertz gives feet), Ohm's law and power, subnet masks from prefix lengths.
- Read the Network+ exam objectives end to end and mark every term you cannot define in a sentence.
- Set up the logbook and the study log. Everything after this is scored from them.
Practice
- HamStudy practice exams
Study mode until it reports 85 percent seen and aced, then timed practice exams only. Log the score.
- HamExam
A second question pool, for a cold check the week before the session.
- Anki
Write your own cards for the formulas and the regulations. Spaced repetition is the answer to passive reading for the whole plan.
Gate
General licence in hand, and fifty mixed arithmetic problems in ten minutes with no errors.
Reading
- HamStudy
The question pools with spaced repetition. Free.
- ARRL licensing, education and training
Where the licence manuals and local exam sessions are listed.
2. On the air, on wire
Weeks 5 to 12
Nothing learned at a keyboard substitutes for having tuned a wire in the rain. This block is the one that no amount of software background covers.
- Buy the transceiver, the analyzer, a spool of wire, coax and the battery. Nothing else yet.
- Build and tune a half-wave dipole, an inverted V and an end-fed half-wave. Sweep each with the analyzer and log the standing wave ratio before and after every trim.
- Build a half-wave dipole fed 14 percent from its centre through a 4:1 balun, and confirm on the analyzer that it works on its even harmonics too. Compute the feed point in feet and inches before you cut.
- Build a long wire, several wavelengths on the band in use, fed at one end against a counterpoise. Log which directions it favours.
- Build the two terminated directional wires: a sloping vee and a vertical half-rhombic, each ended in a 400 to 600 ohm non-inductive resistor. Point them by compass at a distant station and compare against the dipole on the same hour.
- With a multimeter: zero it, prove the continuity of every antenna wire and feedline, and read the battery's voltage, inside ten minutes. Do it before every field build.
- Build a near vertical incidence skywave (NVIS) antenna low to the ground and make contacts inside three hundred miles on 40 and 80 meters, the band that is hard to reach any other way.
- Make one hundred logged contacts from at least five outdoor locations on battery power.
- Run JS8Call and Winlink over HF. Send yourself an email over the radio with no internet in the chain.
- Keep a propagation log: time, band, solar flux, what you could and could not hear. Learn the maximum and lowest usable frequencies from your own data before reading about them.
Practice
- PSKReporter
Where your digital signal was heard and how strong. Change one thing about the antenna, transmit again, compare. Log the difference.
- Reverse Beacon Network
The same for CW and some digital modes: skimmers report your signal-to-noise ratio.
- VOACAP online
Predict a path for a band and hour, then try it. Score your predictions against the log.
- EZNEC
Free antenna modelling. Model it, predict the impedance and pattern, then build it and measure. The gap is the lesson.
- WebSDR
Remote receivers in a browser. Practise tuning, reading a waterfall and hearing NVIS against skip before the rig arrives.
- KiwiSDR public receivers
Hundreds more remote receivers. Listen for your own signal from another state.
Gate
Given a frequency and an azimuth to the distant station: compute the length, cut the wire to within three inches of it, erect it broadside to that azimuth by compass, connect the radio and log a contact, all inside thirty minutes, in the dark, by headlamp. Then the same with the off-centre-fed and a terminated wire.
Reading
- Near vertical incidence skywave
The short explanation. Then the ARRL Antenna Book chapter on it.
- Parks on the Air
The easiest way to make outdoor, battery-powered contacts a habit.
3. Networks
Weeks 13 to 24
Every modern radio is a network node. The operator who cannot subnet is the operator who cannot pass data, whatever the radio can do.
- Work through the Cisco Certified Network Associate (CCNA) official certification guide, and lab every chapter in Packet Tracer as you go.
- Subnet by hand daily until twenty problems take five minutes.
- Build a field network from a pack: travel router, cellular modem, laptop, two phones. Static addressing where it matters, DHCP where it does not, local DNS, and a VPN back to the house.
- Configure a VLAN-segmented network on two real, used managed switches, with routing between the segments.
- Sit the CCNA. If the calendar will not allow it, sit Network+ instead and keep the CCNA as the next block's stretch.
Practice
- Subnetting Practice
Timed subnet drills with instant marking. Log the time for twenty.
- subnetting.net
A second drill site with a different question style.
- Jeremy's IT Lab
The free CCNA course with a Packet Tracer lab file for every lesson. The labs are the practice. The videos are not.
Gate
CCNA passed, or Network+ passed plus a documented field network that is up and passing traffic fifteen minutes after the pack is opened.
Reading
- Cisco Packet Tracer
Free. Every lab in the guide runs in it.
- Professor Messer
The free Network+ video course, if that is the exam you sit.
4. Mesh and the shared map
Weeks 25 to 32
Position and text over a mesh with nothing underneath it is the baseline for a small group outdoors now. It is also the block where the networks block starts paying rent.
- Install the civilian Android Team Awareness Kit (ATAK) on two devices. Learn markers, routes, chat and data packages until they are muscle memory.
- Stand up a TAK server on a single-board computer or a small virtual machine and connect both devices with certificates.
- Build a four-node LoRa mesh. Measure range and hop behavior in woods and in a built-up area, and feed the node positions into the shared map.
- Write a one-page setup card for the mesh that a friend can follow without you standing there.
Practice
- Meshtastic documentation
No site scores a mesh. Time yourself from a cold pack to positions on the shared map, and log it at the gate.
Gate
Two people three kilometers apart with no cellular service, exchanging position and text through the mesh into one shared map.
Reading
- TAK, civilian release
The Android app and the server both come from here.
- Meshtastic documentation
The LoRa mesh, and the plugin that puts it on the ATAK map.
5. Spectrum
Weeks 33 to 40
You can only fix what you can see. A software-defined receiver turns the spectrum into something you can watch, and watching it is how you learn what a healthy link and a broken one look like.
- With the RTL-SDR and a tuned antenna, identify twenty signal types by eye from the waterfall, checked against the Signal Identification Wiki.
- In GNU Radio, build a broadcast FM receiver from blocks, then a decoder for one digital mode, and understand every block in the chain.
- With a directional antenna and an attenuator, enter an amateur radio direction finding event, or hide a beacon and run your own.
- Learn what interference looks like on the waterfall: broadband noise, a carrier parked on the frequency, sweeping and pulsed sources. When it lands on your own link, recognise it, note the time and the shape, change something (band, antenna, power, timing) and get the traffic through anyway.
- Log every interference problem on your own field network and find its physical source. Write down how you found it.
Practice
- PySDR
A free textbook where every idea comes with Python you run against the receiver. Do every exercise. Do not read past one.
- Signal Identification Wiki
Audio and waterfall samples for every signal. Make flashcards of the images, answer on the back, and drill them in Anki.
- WebSDR
Live signal identification against the wiki, from any receiver in the world, any hour.
- ARDF USA
Direction finding events. An event is a scored gate run by somebody else.
Gate
Locate a hidden transmitter inside one hour in terrain you have not walked before.
Reading
- GNU Radio
The tutorials are linked from the front page, and they are the course.
- ARRL direction finding
Radio direction finding: antennas to build, events to enter.
6. Drones and power
Weeks 41 to 48
Small uncrewed aircraft and a power budget are part of field communications now. The drone's links are also the most instructive thing you will ever watch on a waterfall.
- Pass the Federal Aviation Administration Part 107 remote pilot exam.
- Fly a sub-250 gram quadcopter for twenty logged hours: orbits, return-to-home failures, flying by the video feed alone. Find its control and video links on the SDR waterfall and watch what distance does to them.
- Write a seventy two hour power budget for the whole kit: radio, mesh nodes, phones, laptop, drone. Build the solar and battery set that meets it.
- Learn the three battery chemistries you will carry: charge profiles, behavior in the cold, and the rules for carrying them on aircraft.
Practice
- Pilot Institute Part 107 practice test
Free, scored, and every answer explained. Log the percentage.
- Liftoff
The simulator FPV pilots train in. Simulator hours count in the log like real ones. Say which.
- Velocidrone
The other simulator. Either one. Pick the one that runs on your machine.
Gate
Seventy two hours in the field on the budget you wrote. Everything charged at the end, nothing dead in the middle.
Reading
7. Field exercises
Monthly from week 12, all year
A skill you have not used under a time limit outdoors is a skill you have read about. The monthly exercise is where the other six blocks are found out.
- Once a month, twenty four to seventy two hours outdoors carrying the whole kit: HF, mesh, network, power. Set the distance and the load beforehand and do not renegotiate them on the day.
- Before each one, write the communications plan from the template on this page: primary, alternate, contingency and emergency means for every link, a net diagram, the scheduled contact windows in Zulu, the frequencies by time of day, and the power plan. Four hours from scenario to finished plan is the standard.
- Choose the transmission site from the map before you walk: line of sight to the far station for ground wave, or, for sky wave, ridge lines in the direction of transmission no higher than half the take-off angle you need, with room for the antenna and its supports. Then confirm it on the ground.
- Leave the site as you found it: wire, insulators, stakes, tape and batteries all counted back into the pack. A dropped length of wire is a failed exercise.
- Teach one friend with no technical background to put up the antenna and make a contact, using a drawing and plain sentences. If they cannot do it, the teaching is what failed.
- Enter ARRL Field Day, Winter Field Day and at least one park activation, and score each against the last.
- After every exercise, one page: what failed, why, and the one thing that changes before the next one.
Practice
- Parks on the Air
Scored activations. Ten contacts from the park is the standard. Log the count and the time to the tenth.
- ARRL contests
A contest weekend is a timed exercise with a scoreboard.
- Summits on the Air
If the ruck should count for something too.
Gate
Twelve logged exercises in the year, and the last one passes every earlier gate back to back in one weekend.
Reading
- Techniques for Tactical Radio Operations (Army Techniques Publication 6-02.53)
Public doctrine. The chapters on choosing antennas, propagation and communications planning are the best free reference on the subject.
Communications plan template
Standard
From a written scenario to a finished plan on this template inside four hours. The plan is finished when a second person could run the exercise from it without asking you anything.
1. Situation and task
- Who talks to whom, from where, for how long?
- What must get through even if everything else fails?
- Grid and azimuth to every distant station.
2. Means, for every link
- Primary: the means, frequency or channel, antenna, and the hours it is expected to work.
- Alternate: the second means, ready without repacking.
- Contingency: what you fall back to when both are out, and who decides.
- Emergency: the last resort, and the signal that says you are on it.
3. Net diagram
- Every station, every link between them, and the means on each link.
- Which station controls each net.
4. Schedule
- Contact windows in Zulu, with the local time beside each.
- Frequencies by time of day, from the propagation prediction, with the fallback if the band is dead.
- What happens after a missed window: how long to wait, what to try next.
5. Procedures
- Call signs, authentication method, and how a message is formatted.
- What is sent in the clear and what is not.
- Radio checks: when, and what counts as good enough to proceed.
6. Site
- Ground wave or sky wave, and the site chosen for it from the map.
- Antenna, orientation and height at each site, with the space it needs.
- What is left behind: nothing.
7. Power
- Every load in amps, the hours it runs, and the amp-hours that adds up to.
- Batteries carried, with the reserve, and how they are recharged.
- The point at which the plan degrades to save power, and what is cut first.
8. After
- What failed, why, and the one thing that changes before the next exercise.
Reference cards
Cards to carry until the drill makes them unnecessary. They print with the plan template.
Formulas
| Wavelength | λ (m) = 300 / f (MHz) | Feet: 984 / f. |
|---|---|---|
| Half-wave dipole | L (ft) = 468 / f (MHz) | Each leg 234 / f. Cut long, trim to the analyzer. |
| Off-centre feed point | 0.14 × (468 / f) | From the centre. Tenths of a foot × 12 = inches. |
| Quarter-wave vertical | L (ft) = 234 / f (MHz) | Needs radials or a counterpoise. |
| Decibels | dB = 10 log10 (P2 / P1) | 3 dB doubles, 10 dB is ten times, 20 dB is a hundred. |
| dBm | mW = 10^(dBm / 10) | 0 dBm is 1 mW, 30 dBm is 1 W, 37 dBm is 5 W. |
| Ohm's law | V = I R, P = V I = V² / R | |
| Battery | Ah = A × h, h = Ah / A | Keep a third in reserve for cold and cloud. |
| Back azimuth | az ± 180 | Add if under 180, subtract otherwise. |
| Broadside wire | az ± 90 | The wire runs at right angles to the bearing. |
Decibels
| dB | Power ratio |
|---|---|
| 1 | 1.26 |
| 3 | 2 |
| 6 | 4 |
| 10 | 10 |
| 13 | 20 |
| 20 | 100 |
| 30 | 1 000 |
Antenna lengths by band
| MHz | λ (m) | Half-wave | Each leg | 14% feed point |
|---|---|---|---|---|
| 1.9 | 157.9 | 246′ 4″ | 123′ 2″ | 34′ 6″ |
| 3.6 | 83.3 | 130′ 0″ | 65′ 0″ | 18′ 2″ |
| 7.1 | 42.3 | 65′ 11″ | 32′ 11″ | 9′ 3″ |
| 10.1 | 29.7 | 46′ 4″ | 23′ 2″ | 6′ 6″ |
| 14.2 | 21.1 | 32′ 11″ | 16′ 6″ | 4′ 7″ |
| 18.1 | 16.6 | 25′ 10″ | 12′ 11″ | 3′ 7″ |
| 21.3 | 14.1 | 22′ 0″ | 11′ 0″ | 3′ 1″ |
| 28.5 | 10.5 | 16′ 5″ | 8′ 3″ | 2′ 4″ |
Phonetic alphabet
A Alfa
B Bravo
C Charlie
D Delta
E Echo
F Foxtrot
G Golf
H Hotel
I India
J Juliett
K Kilo
L Lima
M Mike
N November
O Oscar
P Papa
Q Quebec
R Romeo
S Sierra
T Tango
U Uniform
V Victor
W Whiskey
X X-ray
Y Yankee
Z Zulu
Prowords
| THIS IS | The transmission is from the station whose call follows. |
|---|---|
| OVER | My transmission is ended and I expect a reply. |
| OUT | My transmission is ended and no reply is expected. |
| ROGER | I have received your last transmission satisfactorily. |
| WILCO | Received, understood, and will comply. Never with ROGER. |
| SAY AGAIN | Repeat all, or the part after ALL AFTER or before ALL BEFORE. |
| I SAY AGAIN | I am repeating the transmission or the part indicated. |
| I SPELL | I shall spell the next word phonetically. |
| FIGURES | Numerals follow. |
| WORDS TWICE | Communication is difficult. Send every phrase twice. |
| CORRECTION | An error has been made. The correct version follows. |
| WAIT | I must pause for a few seconds. |
| WAIT OUT | I must pause longer than a few seconds. I will call you. |
| READ BACK | Repeat this entire transmission back to me exactly. |
| I READ BACK | The following is my reply to your read back request. |
| RADIO CHECK | What is my signal strength and readability? |
| UNKNOWN STATION | The identity of the station I am calling is unknown. |
| BREAK | I separate the text from the rest of the message. |
Zulu offsets
| Eastern Standard | UTC-5 | Zulu = local + 5 h |
|---|---|---|
| Eastern Daylight | UTC-4 | Zulu = local + 4 h |
| Central Standard | UTC-6 | Zulu = local + 6 h |
| Central Daylight | UTC-5 | Zulu = local + 5 h |
| Mountain Standard | UTC-7 | Zulu = local + 7 h |
| Mountain Daylight | UTC-6 | Zulu = local + 6 h |
| Pacific Standard | UTC-8 | Zulu = local + 8 h |
| Pacific Daylight | UTC-7 | Zulu = local + 7 h |
Gear
Bought block by block. Costs are rough and in US dollars. Used and borrowed is fine for all of it.
| Item | For | Cost |
|---|---|---|
| Portable HF transceiver, 20 W class | Every antenna and propagation block. Runs from a small battery | 450 to 650 |
| Vector network analyzer (NanoVNA) | Sweeping and trimming every antenna you build | 60 |
| Wire, coax, insulators, a 1:1 and a 49:1 balun | Dipoles, inverted Vs, end-fed half-waves and NVIS antennas | 80 |
| 12 V lithium iron phosphate battery, 20 Ah, and charger | Field power for the radio and everything charged from it | 150 |
| Software-defined radio receiver (RTL-SDR) with antenna kit | Watching the spectrum. Identifying and locating signals | 50 |
| Four LoRa mesh nodes | The mesh block, then every field exercise after it | 120 |
| Travel router, cellular modem, two used managed switches | The field network and the VLAN lab | 150 |
| Directional VHF antenna and a step attenuator | Direction finding | 40 |
| Sub-250 gram quadcopter | The drone block. Its links are also a target on the waterfall | 400 |
| 100 W folding solar panel and charge controller | The seventy two hour power budget | 200 |