Glossary
Glossary of HFClock Terms
Antipode
- In geography, the antipode of any spot on Earth is the point on Earth's surface diametrically opposite to it. A pair of points antipodal to each other are situated such that a straight line connecting the two would pass through Earth's center. Antipodal points are as far away from each other as possible.
Apogee
- Apogee is the farthest point from the earth.
Azimuthal Map
- The azimuthal equidistant projection is an azimuthal map projection. It has the useful properties that all points on the map are at proportionally correct distances from the center point (the amateur radio operator’s DE position), and that all points on the map are at the correct azimuth (direction) from the center point.
Call Sign
- In broadcasting and radio communications, a call sign is a unique designation for a transmitter station. In the United States of America, they are used for all FCC-licensed transmitters.
DE
– Home radio station position
DST
– Daylight Savings Time
DX
– Remote radio station position
DX Cluster
- A DX cluster is a network of computers, each running a software package dedicated to gathering, and disseminating, information on amateur radio DX (long-distance contact) activities. The computers comprising the network are called nodes, the network itself being termed a cluster of nodes. The nodes may be connected either via radio links or through the internet. Internet nodes generally connect using the telnet protocol. The system acts as an aggregator of information, accepting input from various sources, then making that data available to any user who is connected to the network.
GOES 16 X-Ray
- The GOES x-ray plots shown here are used to track solar activity and solar flares. Large solar x-ray flares can change the Earth’s ionosphere, which blocks high-frequency (HF) radio transmissions on the sunlit side of the Earth. Solar flares are also associated with Coronal Mass Ejections (CMEs) which can ultimately lead to geomagnetic storms.
Lines of Latitude
- Lines of latitude start at 0 degrees at the equator and end at +90 degrees at the North and -90 degrees at the South Poles. ... The five major parallels of latitudes from north to south are called: Arctic Circle, Tropic of Cancer, Equator, Tropic of Capricorn, and the Antarctic Circle
Lines of Longitude
- The lines from pole to pole are lines of constant longitude, or meridians. the Prime Meridian, which passes through the Royal Observatory, Greenwich, England, was allocated the position of 0° longitude. The longitude of other places is measured as the angle east or west from the Prime Meridian, ranging from 0° at the Prime Meridian to +180° eastward and −180° westward.
Long Path
- A situation where HF propagation exists between two stations in the inverse direction of the great circle heading. This means pointing your antenna 180 degrees away from the “short path”, or great circle heading, for a particular station.
Mercator Map
- The Mercator projection is a cylindrical map projection presented by Flemish geographer and cartographer Gerardus Mercator in 1569. It became the standard map projection for navigation because of its unique property of representing any course of constant bearing as a straight segment.
NCDXF
- The International Beacon Project (IBP) is a worldwide network of radio propagation beacons. It consists of 18 continuous wave (CW) beacons operating on five designated frequencies in the high frequency band.[1][2] The IBP beacons provide a means of assessing the prevailing ionospheric signal propagation characteristics to both amateur and commercial high frequency radio users. The project is coordinated by the Northern California DX Foundation (NCDXF) and the International Amateur Radio Union (IARU). The first beacon of the IBP started operations from Northern California in 1979. The network was expanded to include 8 and subsequently 18 international transmission sites.
NTP
- The Network Time Protocol is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks.
Perigee
– Perigee is the closest point from the earth
Planetary Kp
- Used to characterize the magnitude of geomagnetic storms. Kp is an excellent indicator of disturbances in the Earth's magnetic field. The planetary 3-hour-range index Kp is the mean standardized K-index from 13 geomagnetic observatories between 44 degrees and 60 degrees northern or southern geomagnetic latitude. The label 'K' comes from the German word 'Kennziffer' meaning 'characteristic digit. ' The K-index was introduced by Julius Bartels in 1938.
RSS
- Really Simple Syndication, a standardized system for the distribution of content from an online publisher to Internet users.
Short Path
- A situation where HF propagation exists between two stations in the direction of the great circle heading.
Solar Flux
- Solar flux, or concentrated sunlight, is a measure of how much light energy is being radiated in a given area. Solar flux can be characterized by the familiar W/m² or kW/m².
Sunspot Number
- An arbitrary numerical value that is used to describe the sun's spottedness, is the number of individual spots plus 10 times the number of disturbed regions and depends upon the instrumental equipment and personal equation of the observer.
SWPC
- Space Weather Prediction Center
Tropic of Cancer
- Also referred to as the Northern Tropic, is the most northerly circle of latitude on Earth at which the Sun can be directly overhead. This occurs on the June solstice, when the Northern Hemisphere is tilted toward the Sun to its maximum extent.
Tropic of Capricorn
- Is the circle of latitude that contains the subsolar point on the December solstice. It is thus the southernmost latitude where the Sun can be directly overhead.
UTC
- Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time at 0° longitude, and is not adjusted for daylight saving time. In some countries, the term Greenwich Mean Time is used.
VOACAP
- Voice of America Coverage Analysis Program is a radio propagation model that uses empirical data to predict the point-to-point path loss and coverage of a given transceiver if given as inputs: two antennas (configuration and position), solar weather, and time/date. Written in Fortran it was originally designed for Voice of America