📡 Amateur (Ham) Radio

In the U.S. the FCC issues three license classes, earned in sequence. Each is a multiple-choice exam drawn from a public question pool, administered by volunteer examiners (VEs). No Morse code is required for any class today. A license is valid for 10 years; there's a $35 FCC fee.

How a lot of the exam overlaps with CET study: the electronics on the Technician exam — Ohm's law, power, schematic symbols, basic components — is the same material the Circuits Lab and Ohm's Law Wheel teach, and the radio theory is the RF guide. So if you're prepping for the CETa, you're already most of the way to a Technician license.

Once licensed, operating is its own skill — knowing the bands, the modes, and the shorthand. Quick reference to get you on the air.

The band plan — pick a license class and see exactly where you can transmit. Each bar is one band; lit segments are where that class has privileges, colored by mode. Tap any band for the details.

Phonetic alphabet — used to spell call signs clearly over noisy channels: Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliet, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu.

A few common Q-codes (shorthand that started in Morse, still used in voice): QTH = my location; QSL = I acknowledge / confirm; QRZ = who is calling me?; QRM = interference; QSB = your signal is fading; QSO = a contact/conversation; 73 = best regards.

You passed the exam and you have a call sign — now what? This is the part nobody explains well. Here's how to actually key up for the first time without spending a lot or getting overwhelmed.

Start with a handheld. A handheld transceiver (an HT, or "handy-talkie") is the near-universal first radio, and for good reason: it's the cheapest way in, it works out of the box, and it gets you on the air the same day. A pocket radio teaches you repeaters, simplex, and basic operating with zero installation — no antenna to put up, no power supply, no coax run. The bigger station types are real, but they're things you grow into:

What to look for in a first HT: get a dual-band radio (2 meters and 70 centimeters) so you can reach the most repeaters, with at least 5 watts for a good balance of range and battery life. Skip digital voice at first — modes like D-STAR, System Fusion, and DMR add real cost and menu complexity, they aren't compatible with each other, and most repeaters are still plain analog FM. A simple analog FM handheld is the cleanest place to learn. You can always go digital later once you know what your local club actually uses.

One upgrade that punches above its price: swap the stock "rubber duck" antenna for a longer aftermarket whip. It's the cheapest way to noticeably improve how far you can hit repeaters — antenna gains almost always beat power gains. When you're ready to understand why, the Antenna Theory guide covers it.

Repeaters are how most Technicians make most of their contacts — and they're the source of the most common new-ham frustration: "I can hear them perfectly, so why can't I talk to them?" The answer is almost always one of three settings. Here's how a repeater actually works.

Why repeaters exist. A handheld putting out a few watts into a stubby antenna doesn't reach far — line-of-sight, maybe a few miles. A repeater is an automated station sitting somewhere high (a tower, a tall building, a mountaintop) with a sensitive receiver and a powerful transmitter. It listens for your weak signal and instantly re-transmits it, loud, from its high perch. Your 5-watt pocket radio effectively borrows a 50-to-100-watt station on a mountain — suddenly you're covering a whole metro area.

The offset — this is the big one. A repeater can't listen and transmit on the same frequency at once (it would deafen itself with its own signal — instant feedback). So it uses two frequencies: it listens on one and transmits on another. The gap between them is the offset. You tune your radio to the repeater's output (the frequency you hear), and when you key up, your radio automatically transmits on the input frequency — shifted by the offset. This is why you can hear a repeater but not reach it: if your offset is off, you're listening in the right place but transmitting in the wrong one.

Handy memory aid: higher frequency, higher offset (2 m uses 600 kHz; 70 cm uses a much bigger 5 MHz). These are conventions set by regional frequency coordinators, not FCC law — so check a directory for any specific machine. The good news: virtually every modern radio sets the offset automatically once you enter the output frequency.

The tone (CTCSS / PL). Most repeaters also require a CTCSS tone — a low, sub-audible tone (like 88.5 or 110.9 Hz) your radio sends underneath your voice. The repeater won't open up unless it hears the right tone. It's how a busy area keeps repeaters from keying each other up and rejects stray interference. You'll also hear it called a PL tone (Motorola's brand name, "Private Line"). It is not privacy or encryption — anyone can still hear you; it's just an access key. Get the tone wrong and you'll hear the repeater fine but it'll ignore you completely.

Simplex vs. duplex. Going through a repeater is duplex operation — two frequencies (in and out). The opposite is simplex: you transmit and receive on the same frequency, radio-to-radio, no repeater in between. Simplex is how you talk directly to someone close by — and good etiquette, since it doesn't tie up a repeater that everyone shares. The national 2-meter simplex calling frequency is 146.520 MHz; call there, then move to another simplex frequency to chat. A good habit: if the other station is close enough, drop to simplex and free the repeater.

Tune across a band and you'll hear a language of its own: "QRP DX on simplex, no copy, QSB, 73." None of it is hard once you know the words. Type in the box to filter, or just scan — the terms you'll hear most are here.

No terms match that — try a shorter word.

The fun part: putting up antennas. These calculators and the visual build lab cover everything from a first dipole to multiband and directional antennas. (These tools have always been on the site — this is their home.)

Start here if you're new to antennas: a half-wave dipole is the classic first antenna — cheap, effective, and the reference all others are compared to. Cut it for your band, feed it with coax, and you're on the air.