high-frequency communications

high-frequency (HF) communications

The communications carried out at frequencies between 3 and 30 MHz. HF waves are dependent mostly on reflected sky waves and are affected by ionospheric conditions. HF is used for long-range communications. The lower frequencies in this range are more suitable at night, and the higher frequencies are more suitable for day operation. Expected ranges may vary up to 15,000 NM or more.
References in periodicals archive ?
Contract Awarded to Upgrade the Australian Defence Force%s (ADF) defence high-frequency communications system (DHFCS)
Fushi Copperweld's bimetallic conductors offer a cost-saving alternative to solid copper wire in a variety of applications, including electrical earthing/grounding, and high-frequency communications cables.
He added: "I believe this application will have tremendous implications in high-frequency communications and electronics.
Army for Falcon II AN/VRC-104(V)(3) radio systems to provide high-frequency communications in multiple variants of Mine Resistant Ambush Protected vehicles (MRAPs).
High-Frequency Communications -- Cubic is making inroads in the military community with the integration of its HF power amplifiers aboard U.
The Mission Modules for the AN/PRC-117G provide the radio with additional functionality such as a second wideband channel, high-frequency communications, ISR and jamming.
Additional Rockwell Collins equipment includes: traffic alert and collision avoidance system, air data system, high-frequency communications, centralized maintenance system and an array of optional equipment such as VHF data link and satellite communications systems.
The satellite, designated DSCS III A3, represents the third of four super high-frequency communications satellites to feature Service Life Enhancement Program (SLEP) upgrades, that will provide improved uninterrupted secure voice and high data rate communications to its Department of Defense users.
Designated DSCS III A3, the spacecraft represents the third of four super high-frequency communications satellites to feature Service Life Enhancement Program (SLEP) upgrades, that will provide improved uninterrupted secure voice and high data rate communications to its Department of Defense users.
DOD will use these profiles to improve high-frequency communications and other systems that use the ionosphere for propagation.
The DSCS III B11 spacecraft, the second of four super high-frequency communications satellites to feature Service Life Enhancement Program (SLEP) upgrades, was launched in October 2000, with two more SLEP satellites remaining to be launched.
The DSCS III B11 spacecraft, the second of four super high-frequency communications satellites to feature Service Life Enhancement Program (SLEP) upgrades, will provide improved uninterrupted secure voice and high data rate communications to its Department of Defense users.

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