SYS: ONLINE|UTC --:--:--|BAND: 20m
SWR: 1.2PWR: 100WQTH: EN52
// Propagation

Understand the station before you build it

Twenty-eight reference drawings, three calculators and four interactive models covering the whole signal path — from the licence exam to the radiation pattern.

f: 1.8-30 MHzZ: 50 ohmP: 100 W
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Independent

No manufacturer pays for a mention, and nothing here is for sale.

Educational

Written as a reference for the principles, not as a product guide.

Four free 3D tools

Interactive models that need no account and no download.

Safety first

RF exposure, high voltage and antenna work are flagged throughout.

Categories

Five families of equipment

All 28 references →

Feedline & Connectors

Getting power from the shack to the antenna without losing it on the way.

6 references→

Power & Grounding

Safe, quiet DC for the rig — and a path to earth when the sky turns.

5 references→

Test Equipment

Measure it instead of guessing. The instruments that answer "why is it not working?"

6 references→

Operating & Logging

The human interface: logging contacts, sending CW, and being heard.

5 references→
Process

Four steps from nothing to on the air

  1. License & Setup1
    Step 1

    License & Setup

    Sit the entry examination, get a call sign, and choose a first radio that you can actually use where you live.

  2. Antenna & Feedline2
    Step 2

    Antenna & Feedline

    Get something in the air. A well-built dipole at a reasonable height beats an expensive antenna at a poor one.

  3. Operating & Logging3
    Step 3

    Operating & Logging

    Make contacts and record every one of them. The log is what turns a contact into an award.

  4. Propagation & DX4
    Step 4

    Propagation & DX

    Learn when the bands open, and work with the ionosphere instead of against it.

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3D Studio

Four models you can turn over in your hands

Antenna radiation patterns, a matching network you adjust by hand, an ionospheric propagation model, and a Morse trainer with real audio. Each one is a simplified simulation built to make a principle visible.

Radiation PatternSWR & TunerPropagationMorse Trainer
Most referenced

Popular tool references

See all →
HF Transceiver engineering reference drawing
Setup

HF Transceiver

The main station radio: 160 through 10 metres, all-mode, 100 W class.

f: 1.8-30 MHzP: 100 W
Transceivers→
Dipole Antenna engineering reference drawing
Antenna

Dipole Antenna

Two equal wires and a feed point. The reference antenna everything else is compared against.

L: 468/f ftZ: 73 ohm
Transceivers→
Coaxial Cable engineering reference drawing
Antenna

Coaxial Cable

The standard unbalanced feedline: centre conductor, shield, and the dielectric between them.

Z: 50 ohmloss: 2.1 dB/30m
Feedline→
SWR Meter engineering reference drawing
Test

SWR Meter

The inline instrument that tells you how much of your power is coming back.

SWR: 1.0-3.0P: 5-200 W
Test Gear→
Vertical Antenna engineering reference drawing
Antenna

Vertical Antenna

A quarter wave standing up, with radials underneath. Small footprint, low radiation angle.

H: lambda/4Z: 36 ohm
Transceivers→
Yagi Beam engineering reference drawing
Antenna

Yagi Beam

A directional array that concentrates your power where you point it.

G: 10.5 dBiF/B: 20 dB
Transceivers→
Power Supply engineering reference drawing
Power

Power Supply

Clean regulated DC for the station, sized for the current the radio actually draws.

V: 13.8 VI: 30 A
Power→
VHF/UHF Handheld engineering reference drawing
Setup

VHF/UHF Handheld

A pocket radio for local contacts, repeaters and public-service work.

f: 144-148 MHzf: 430-450 MHz
Transceivers→
Antenna Tuner engineering reference drawing
Antenna

Antenna Tuner

An adjustable matching network that lets one antenna cover several bands.

f: 1.8-30 MHzZ: 6-1000 ohm
Transceivers→
Calculators

Three calculators that answer real questions

Antenna Length Calculator

Work out the length of a dipole, vertical, 5/8 vertical or full-wave loop from the frequency you want to work.

Free tool→

SWR & Power Calculator

Convert between forward power, reflected power, SWR, reflection coefficient and mismatch loss.

Free tool→
Reading

From the blog

All articles →
Feedline and SWR: What Every Ham Should Know
Antenna/24 February 2026/12 min

Feedline and SWR: What Every Ham Should Know

SWR is not a measure of how well your antenna works. It is a measure of how well it matches — and those are different questions.

Petter Lindqvist→
Start here

New to the hobby?

Begin with the licensing guide, then work through the four steps. Everything on this site assumes you are starting from nothing.

Read the licensing guideBrowse the toolkit

Tool Categories

Transceivers & AntennasFeedline & ConnectorsPower & GroundingTest EquipmentOperating & Logging

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