HF

"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 the higher frequencies go further in daylight and the lower frequncies go further at night.

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

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

The best way to describe Utility (Ute) monitoring is to use negative logic; it excludes CB, Amateur and Short Wave Broadcast. This includes, but is not limited to, aeronautical stations, digital signals (outside of the specified amateur bands), military, maritime, federal and other users. See our Utility Monitoring page for more information and links.

Utility Topics

• ALE
• COTHEN
• HF Aeronautical Communications
• HF Digital Decoding
• HF Maritime Communications
• HF Military Communications
• ICE - Monitoring U.S. Immigration and Customs Enforcement HF Operations
• 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