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.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
'Worldwide high-frequency communications is what our commercial customers do every day using virtually every mode of operation and type of propagation,' said Gerald Youngblood, CEO of FlexRadio.
"This is the region of the ionosphere that affects high-frequency communications and navigation signals," Laura Hayes, solar physicist at NASA Goddard and Trinity College in Dublin, Ireland, said in the release.
They are capable of significantly disrupting the world's technology, including GPS systems, power grids, and high-frequency communications. These solar storms currently can only be forecast 30-60 minutes before they reach Earth, greatly hindering the mitigation of their effects.
The company's Subnet Node Controller-2050 system provides high-frequency communications using a high-speed modern to automatically set up ad hoc networks between ships at sea.
He added: "I believe this application will have tremendous implications in high-frequency communications and electronics."
A professor of electrical engineering at UH-Manoa, Shiroma specializes in secure, high-frequency communications systems that could someday link nanosatellites to each other as they spin around the Earth.
A new range of low-profile standard-size RFI screening cans is now available for controlling EMI/RFI in microwave and high-frequency communications applications.
In fact, Meyerson sees the technology becoming a standard for high-frequency communications applications.
Engineering Research Associates, an E-Systems subsidiary located in Vienna, VA, has been awarded a $21.8 million increment of a $40.8 million competitive contract to provide the US Army with an enhanced version of an automated transportable high-frequency communications intercept collection and emitter location system called Enhanced Trackwolf.

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