high frequency

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high frequency

a radio-frequency band or radio frequency lying between 3 and 30 megahertz
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

high frequency

[′hī ¦frē·kwən·sē]
(communications)
Federal Communications Commission designation for the band from 3 to 30 megahertz in the radio spectrum. Abbreviated HF.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

high frequency

The frequency band between 3 and 30 MHz. This normally is used for long-range air-to-ground communications.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved

HF

(High Frequency) A range of radio frequencies from 3 to 30 MHz. The HF band is used for amateur radio, marine, aviation and military communications and high-frequency RFID tags.

With regard to audio, high-frequency waves are typically above 3,000 Hz. See frequency bands.

high-frequency trading

Buying and selling large quantities of stocks in split seconds, and making pennies or fractions of a penny per share. High-frequency trading (HFT) is performed entirely by computer algorithms that look for and take advantage of small price discrepancies of the same stock on different exchanges. HFT computers are constantly bidding and offering 100-share lots of thousands of different stocks to determine moment-to-moment prices. In addition, traders can spoof the market by placing large sell orders, cancel them milliseconds later and immediately buy the stocks at a lower price, which they caused by injecting negativity into the market.

High-frequency traders are competing with other high-frequency traders all day long. In order to profit, the buys and sells must be executed immediately, and the shorter transmission pathways between orders and executions make the difference. To speed up the process, high-speed traders locate their computers within the same datacenter as the stock exchange computers or as close by as possible. In the most extreme example, a fiber optic line was laid from New Jersey to Chicago in the straightest line possible in order to shave nanoseconds from the travel time. The futures exchange is in Chicago, and New York-based stock exchanges have their datacenters in New Jersey.

Extremely Controversial
Proponents claim high-frequency trading is simply an advanced form of algorithmic trading like all the other widely used financial formulas. High-frequency traders also claim their systems make a more uniform market and have a stabilizing effect.

Opponents claim HFT is downright deceitful, turning money making into software that executes 99% of its trades with a profit. They claim high-frequency traders make billions per year without contributing any value to anyone but themselves. In the Flash Crash of May 6, 2010, when the Dow swung 1,000 points within minutes, regulators reported that high-frequency trading exacerbated market volatility after the sale of unusually large futures contracts. Had the event occurred at a different time of the day, the effects might have reached around the world. As a result, opponents assert that high-frequency trading could turn the market into greater bouts of chaos in the future.
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References in periodicals archive ?
The L3Harris Falcon Wideband Airborne HF Radio features embedded encryption, electronic counter-counter measures (ECCM), low probability of intercept and low probability of detection (LPI/LPD) and is upgradable to accept new waveforms and software delivered capabilities.
Understanding signal propagation and techniques of antenna employment have faded, as has the functional use of existing HF radios. Simultaneously, the cadre of experienced HF instructors has retired and hasn't been replaced, resulting in a lack of genuinely experienced personnel with a strong background in the use of high frequency equipment throughout the armed services.
(25) (Miller, also credited with contributing to Mirick's receiver, would spend much of his career developing the piezoelectric crystal hardware and theory necessary to standardize and measure HF radio.) (26)
Le Guen, "HF 125 W half-loop antennas in ALE and ECCM for land mobile, navy and helicopter use," HF Radio Systems and Techniques, No.
With only weak HF radio contact, they elected to turn back towards the mainland and run the checklists further.
Until two years ago the kids in remote communities and on cattle stations had to learn over a crackly HF radio. Now satellite broadband has come to the Outback and allows Window to teach kids online.
"These advanced HF radio systems will be used for the Army's Modularity Program and to address the critical needs of the Army National Guard and Reserve," said Dana Mehnert, vice president and general manager of business development and operations, Harris RF Communications Division.
We pay a whopping $2,405 every time the ARC-220 HF radio control head, NSN 5821-01-413-4243, gets damaged.
The Belgian-Norwegian communication systems developer Zenitel said today (14 February) that its subsidiary Zenitel Netherlands BV had secured three new contracts for HF radio communication systems.
Before switching to satellite last year, MEDjet had relied on HF radio communications, but the signal was subject to interference from storms and wasn't as secure as it needed to be.
To counter the problems inherent in all the above mentioned communications options, the British electronics group Racal has been selling an HF radio system, for secure long-range voice and data telecommunications since the early 1990s.