Introduction to HF
HF - "high frequency", the shortwave bands - is the part of amateur radio that reaches other continents with a hundred watts and a piece of wire, with nothing in between but the sky.
Why HF is different
VHF and UHF signals travel in more or less straight lines, so a handheld reaches the horizon or the nearest repeater. HF signals bounce off the ionosphere, an electrically charged layer high above the earth, and come back down hundreds or thousands of miles away. No towers, no internet, no infrastructure of any kind - which is the whole appeal.
The bands, in plain terms
| Band | What it is good for | When |
|---|---|---|
| 80 m | Regional chat and local nets, big antennas | Night |
| 40 m | The reliable all-rounder - regional by day, continental at night | Day and night |
| 20 m | The classic long-distance band: other continents, most days | Daylight |
| 15 m and 10 m | Spectacular when the sun is active, dead when it is not | Daylight, good years |
Conditions change with the time of day, the season and an eleven-year solar cycle. Part of the fun is that the same setup performs differently every evening.
What licence you need
In the United States, Technician gives you a small slice of HF - notably part of 10 m, and Morse-code segments on 80, 40 and 15 m. General is the one that opens up most of the HF bands for voice, and it is the reason most people upgrade. Compare the licence classes.
What you need to get on HF
- A transceiver covering the HF bands, typically 100 watts. Used radios are plentiful and hold their value.
- A power supply - HF radios want around 20 amps at 13.8 volts.
- An antenna. This matters more than the radio. A simple wire dipole cut for one band, up as high as you can get it, outperforms an expensive radio on a poor antenna every time.
- An antenna tuner, often built into the radio, to keep it happy across bands.
- A good earth and some common sense about RF safety - HF power near people and feedlines deserves respect.
Living somewhere with no room for antennas is not a barrier: attic wires, magnetic loops, end-fed wires along a fence and portable operating from a park all work.
Modes you will hear
- SSB voice - the standard way to talk on HF. Upper sideband above 10 MHz, lower sideband below it.
- CW (Morse) - no longer required for any licence, still remarkably effective with low power.
- FT8 and other digital modes - the computer does the work and gets through when nothing else will. Many people make their first intercontinental contact this way.
Your first HF contact
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Listen across a band for an evening
Get a feel for how people call, and how fast contacts go.
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Answer someone rather than calling
Find a station calling "CQ" with a clear signal and reply with your callsign in phonetics. Answering is much easier than being the one calling.
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Exchange the basics
Signal report, name, location. Many HF contacts are just that, especially when the band is busy.
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Log it and confirm it
Enter it in your log and upload it, so both of you get the confirmation. Setting up QRZ.
Try before you buy
Ask a club member to let you operate their HF station, or go along to a field day. An hour on someone else's radio tells you more than any amount of reading, and costs nothing.