HF

Welcome to the RadioReference HF Gateway. "HF" is an abbreviation for "High Frequency." See Spectrum.

High frequency communications occur in the 2-30 MHz band. Signals in this band can be refracted by the ionosphere allowing worldwide propagation. The distance varies depending on time of day, the solar cycle and current solar and geomagnetic activity, but in general it's best to listen below 10 mhz at night, above this during the day. Our HF Propagation article has links that describe these phenomenon in greater detail.

Many of the FAQs linked here are courtesy of DXing.Com from Universal Radio of Reynoldsburg Oh. and the Monitoring Times website.

• Wikipedia article on SW Radio
• Commonly Used Modes
• Frequency Ranges and Uses
• Frequency vs.Wavelength
• Glossary of Terminology
• Terms and Abbreviations
• UTC and GMT

The RR forum for this topic can be found here

Amateur Radio

• Amateur Radio on HF

Citizen's Band

• See the Citizens Band page for frequencies and channels
• REACT

Short Wave Broadcast

• SWL Broadcast
• Pirates and Clandestines

Utility Monitoring

• Utility Monitoring

Utility Topics

• ALE
• COTHEN
• Federal Aviation Administration
• HF Aeronautical Communications
• HF Digital Decoding
• HF Maritime Communications
• HF Military Communications
• ICE - Monitoring U.S. Immigration and Customs Enforcement HF Operations
• United States Coast Guard
• USAF High Frequency Global Communications System

Equipment

• For links to antennas, reviews, modifications and filters, see our HF Equipment and Accessories article

Online HF Receivers

There are quite a few receivers online that you can listen to HF communications. Some of them even allow you to control the radio for limited times. Some others are set to a specific frequency on the HF band that usually has a lot of activity. See the Live Tunable Receivers article