Amateur Radio · Start here

What's in a station?

Every amateur radio station does the same three jobs: turn your message into a radio signal, send it out an antenna, and do the reverse for whatever comes back. Here's the simplest version, and then a fully equipped one.

A simple station A fully equipped shack How a message travels
Diagram 1 · The simple station

A radio and an antenna, plus a computer for digital modes

Voice and Morse code (CW) need nothing more than a radio and an antenna. Add a computer and you can send email and text too. Switch between transmit and receive to follow the signal.

1Optional

Computer

Runs the software for digital modes. Voice and CW don't need it.

2USB cableaudio · PTT · rig control
only with a computer
3

Radio

Makes and receives the radio signal.

4Coax cablecarries the signal
5

Antenna

Turns that signal into radio waves, and back.

12 V DCpowers the radio
6

Power

A supply on wall power, or a battery.

↑ Powers the radio (3)

Transmit: from keyboard to airwaves

  1. 1
    You write the message. Type it into your software. (For voice or CW, you'd use a microphone or Morse key plugged straight into the radio and skip the computer.)
  2. 1
    The software turns it into sound. A program called a modem converts your text into a stream of audio tones.
  3. 2
    The cable hands it to the radio. The audio travels over the USB cable, and a control signal tells the radio to start transmitting (PTT, push-to-talk).
  4. 3
    The radio makes the signal. It puts your audio onto a carrier at the frequency you chose and amplifies it to the power you set.
  5. 4
    Coax carries it to the antenna. Shielded cable keeps the signal in and the noise out.
  6. 5
    The antenna sends it out. It launches the signal as radio waves that can travel across town, around the world, or up to a satellite, depending on the band.

Receive: from airwaves to screen

  1. 5
    The antenna catches a signal. Passing radio waves induce a tiny electrical current in it.
  2. 4
    Coax brings it down to the radio.
  3. 3
    The radio picks out the station. It tunes to your frequency, filters out everything else, amplifies the signal, and turns it back into audio.
  4. 2
    The cable delivers the audio. The same USB cable carries the sound to the computer.
  5. 1
    The software decodes it. The modem turns the tones back into text you can read.

No computer? Voice and CW skip steps 1 and 2: the microphone or key connects to the radio directly, and you hear the other station through the radio's speaker or headphones.

1

Computer

Runs the software that turns text into sound and sound back into text. VarAC and Winlink Express (radio email) are examples.

OptionalYou only need a computer for digital modes. Voice and CW contacts go straight through the radio, using a microphone or a Morse key.
2

USB cable

Carries the audio both ways and tells the radio when to transmit. It can also let the computer change the radio's frequency and mode, which is called CAT control.

Good to knowOnly needed when a computer is involved. Many modern radios have a built-in USB sound card, so one cable does it all. Others use a small interface box.
3

Radio

The heart of the station. It makes the signal on the frequency you choose and picks incoming signals out of the noise.

Good to knowHandhelds and VHF/UHF radios are mostly for local contacts; HF radios can reach around the world. A handheld puts out about 5 watts, a typical HF base radio about 100.
4

Coax cable

Shielded cable that carries the signal between the radio and the antenna.

Good to knowSome signal is lost along the way, more so at VHF and UHF, so short runs of good cable pay off. An SWR meter or antenna tuner often sits in this line.
5

Antenna

Turns the electrical signal into radio waves, and captures incoming ones. It's often the most important part of the station.

Good to knowA higher, clearer antenna usually beats more power. HF might use a simple wire dipole; VHF and UHF a small vertical on a roof or mast.
6

Power

Radios typically run on 12 volts DC, from a power supply plugged into the wall or from a battery.

Good to knowMany stations use both, so an outage doesn't take them off the air. See how W2JKT does it →
Diagram 2 · The fully equipped shack

The same idea, all grown up

Add more radios, an amplifier, a tuner, and several antennas, and the chain gets longer, but it's still radio, then cable, then antenna.

A fully equipped amateur radio station An optional computer controls three radios over USB. The first HF radio feeds an amplifier, then a tuner with SWR meter, then a coax switch that selects between an HF wire dipole and an HF vertical. The second HF radio connects to its own beam antenna, and the VHF/UHF radio to its own vertical antenna. All antenna cables pass through an entry panel with surge protection and ground. The computer also connects to the internet. SHACK (INDOORS) OUTDOORS ENTRY PANEL · SURGE PROTECTION · GROUND USB · audio + control Ethernet 100 W 1 kW Internetoptional Computeroptional HF radioworldwide HF radio #2worldwide VHF/UHF radiolocal · APRS Amplifierboosts power Tuner + SWRmatches antenna Coax switchpicks antenna HF wire dipolesimple, multi-band HF verticalsmall footprint HF beamdirectional, rotatable VHF/UHF verticallocal coverage

Swipe sideways to see the whole diagram.

Radio signal (coax) USB: audio and control (optional) Internet (optional) Where the cables enter the building
HF radio
The main transceiver, covering the shortwave bands for contacts across the country and around the world. Typically about 100 watts.
HF radio #2
Lets you listen or work on a second band at the same time, such as digital messages on one while chatting on another.
VHF/UHF radio
Handles local work: repeaters, APRS, and nearby friends, usually within tens of miles. It uses its own antenna, since VHF and UHF antennas are different from HF ones.
Computer
Optional. It runs digital-mode software and logging, and over USB it carries each radio's audio and can control frequency, mode, and push-to-talk. Voice and CW work fine without one, straight through each radio's microphone or key jack.
Amplifier
Boosts the radio's roughly 100 watts up to around a kilowatt. In the US the limit on most bands is 1,500 watts PEP. It sits between the radio and the tuner and has its own AC power.
Tuner + SWR meter
Matches the antenna to the radio so power isn't reflected back and wasted. The SWR meter shows how good the match is.
Coax switch
Sends the signal to whichever antenna you select, so several antennas can share one radio.
Entry panel
Where the cables come into the building. Surge arrestors and a solid ground connection here help protect the equipment, and you, from lightning-induced surges.
HF antennas
A wire dipole is the classic simple choice. A vertical takes little room. A beam concentrates your signal in one direction and is turned with a rotator.
VHF/UHF vertical
An all-around antenna for local coverage, usually mounted high on a mast or roof.
Internet
Optional, but handy for logging, Winlink gateways, APRS-IS, and operating the station remotely.

Keeping it all running

Radios run on about 13.8 volts DC. A common setup keeps a battery charged behind the power supply, so the station rides through an outage on battery, with solar or a generator as optional backups.

Wall power
AC from the grid
DC supply
AC to 13.8 V DC
Battery
kept topped off
Fused distribution
one fuse per radio
Radios
on 12 V DC
Solar panels
optional
Generator
optional
Charge the battery
through a charger

Amplifiers usually plug into AC power directly (often 240 V), so they need their own outlet or a generator.

For a sense of scale, W2JKT has two HF radios, two VHF/UHF radios, an amplifier, and an automatic tuner, all backed by a large battery bank. See the equipment list →

Range · Local or worldwide

Why two kinds of radio?

Handhelds and VHF/UHF radios are mostly for local communication, while HF can go around the world. Which you use depends on how far you want to reach.

Mostly local

Handhelds and VHF/UHF

HandheldHandheld Repeater The horizon blocks a direct path

These signals travel in a straight line, so the horizon and hills limit the range. That's plenty for talking across town. A radio on a tall tower, called a repeater, can hear you and rebroadcast your signal much farther.

Typical reachA handheld: a few miles. A mobile or base radio with a good antenna, or a repeater: tens of miles. Satellites and the ISS are the exception, since they're straight up, not over the horizon.
Worldwide

HF (shortwave)

IONOSPHERE bounces back to Earth YouFar away

HF signals bounce off the ionosphere, a layer of the upper atmosphere, and come back down far beyond the horizon. On just a few watts you can reach other continents, and a signal can hop more than once to go even farther.

What to expectWhich band works best changes with the time of day and the sun, so part of the fun is finding where your signal is going today.
Every size

And smaller still

The same three jobs (radio, antenna, power) show up in much smaller packages.

Handheld

Radio, antenna, and battery in one pocket-sized unit. Its reach is mostly local, which is plenty for hiking, events, and chatting through a repeater, and it's a popular first radio.

Mobile

A radio installed in a car or truck, with the antenna on the roof or trunk and power from the vehicle's 12-volt system. More power and a better antenna than a handheld.

Portable

A radio, a battery, and a lightweight antenna in a backpack, set up in a park, on a summit, or at a campsite. See a portable setup →

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