HF is where amateur radio reaches other continents without infrastructure. Signals refract off the ionosphere; which band works depends on the time of day, the season and the solar cycle — see propagation.
Choosing a band right now
Rule of thumb: the higher bands (20 m and up) work in daylight, the lower bands (40 m and down) work at night. If 20 m is full of signals in the afternoon, that is your answer. Digital tools such as PSK Reporter and the DX cluster show live openings.
Calling CQ
"CQ CQ CQ, this is KX4XYZ, kilo x-ray four x-ray yankee, CQ and standing by."
Listen first, then ask "Is this frequency in use?" twice before you start. Somebody weak may already be there.
The exchange
A casual contact — a "ragchew" — covers signal report, name, location, then station, weather and whatever else. A contest or DX contact may be five seconds long and contain a signal report only. Match the pace of whoever you are working.
Working DX
- Listen far longer than you transmit.
- Send only your call sign, once, at the right moment.
- Learn to hear whether the DX station is working split frequency, and where they are listening.
- Do not call while someone else is completing a contact.
Nets and calling frequencies
Every band has established net times and calling frequencies. Avoid transmitting on a net frequency during its scheduled net, and stay clear of recognized emergency and QRP calling frequencies.
Antennas matter more than power
An efficient antenna in the clear beats an amplifier feeding a compromise antenna, every time. See antennas.