Acquisition circle - A circle drawn around a groundstation and referenced to a specific satellite. The satellite is 'in range' when the ground track is inside this imaginary circle.
Anomalistic Period - The time taken between two successive perigees.
Argument of Perigee - An angle locating the satellite in the orbital plane.
One of the classic Kepler Elements.
Armstrong Method - Pointing your antennas by hand - rotating your antenna system by turning your antenna mast by brute force! Don't knock it .. it works .. and is a lot cheaper than a rotator system. Make sure you have a means to 'lock' your antennas in place during windy weather.
Ascending node - The point on a satellite's orbit where it crosses the earth's equator heading North. See equatorial plane.
Autotransponder - A ROBOT type device on board a satellite (RS Series) designed to respond to calls from signals directed to it from the ground. Stores the received information for QSL’ing.
Boresight - The direction of greatest gain of a satellite’s antenna.
Also refers to the point on the earth’s surface where the maximum signal level is ‘aimed’.
Descending node - The point on a satellite's orbit where it crosses the earth's equator heading South. See equatorial plane.
Desensing - The degradation of received signals due to locally generated QRM - interference from your computer or a harmonic of your transmitter.
Eccentricity - A ratio used to describe the 'shape' of an orbit.
The ratio of 'width' to 'length' of the satellite's orbit.
Typical ranges are from 0.001 (near circular) to 0.6 (highly elliptical).
One of the classic Kepler Elements.
Elmer - A person with experience in satellites who offers help and guidance to newcomers. Note - Elmers are unpaid volunteers so don’t call them at unreasonable times or make unreasonable demands of them.
Equatorial plane - An imaginary plane extending out from the equator (usually of the earth). Used to define the ascending and descending nodes of a satellite.
ESA - European Space Agency.
EZ-SAT - A term used to describe easy to use satellites.
GATEWAY - (Satellite GATEWAY) - A digital groundstation used to pass messages between an orbiting satellite and the AX25 Packet Radio network.
Increment - The change in Longitude between successive passes of a satellite, measured in degrees per orbit.
LEILA - An acronym for "LEIstungs Limit Anzeige" which is German for "Power Limit Indicator".
LISTSERVER - An
automatic internet mailing system, used to disseminate messages for special
interest groups to ‘subscribed’ users .
Mean anomaly -A number used to locate the satellite within the orbital ellipse ranging from 0=perigee through 128=apogee. It has a range of 0 to 256. Used to schedule transponder switching at various points in the orbit of the Phase 3 satellites.
Mean motion -The number of orbits (revolutions) of a satellite in a solar day (1440 minutes).
MODEM- (MOdulator - DEModulator) a means of converting analogue signals into digital (and vice-versa).
NASA - North American Air and Space Administration.
OSCARLOCATOR - A manual tracking system for satellites consisting of a Polar Map and a movable plastic overlay. Used in conjunction with Equator Crossing (EQX) tables. Now considered obsolete.
POLAR MAP - A map of the Earth taken from the perspective of 'looking directly down on the North or South Poles'. Such a map is circular in shape with the equator forming the outer edges of the map and the Pole 'dead-centre'.
RAAN - Right Ascension of the ascending node. Wins the prize for the most horribly named KEPLERIAN element.
A number specifying the angle between the satellite’s orbit plane and a fixed point in space -(first point of Aries). Defines the orbit plane orientation in relation to the celestial background.
One of the classic Kepler Elements.
RUDAK (RUDAK-U) - A computer based modulator - demodulator system on board the P3D satellite for use by digital users.
Sidereal day - A time interval of 1436.07 minutes. This is the time taken for the earth to rotate 360 degrees against the stellar background.
Solar day - A time interval of 1440 minutes (24 hours). In this period of time, the Earth rotates slightly more than 360 degrees against the stellar background.
Sub satellite point - The point on the Earth's surface on an imaginary line drawn between the satellite to the centre of the Earth.
TNC - Terminal Node Controller. A type of specialised MODEM used in packet radio systems.
TVRO - TeleVision Receive Only. A ground terminal designed to receive transmissions from orbiting satellites (usually commercial).
The newcomer to satellite operating will undoubtedly encounter other ‘space’ related terms and phrases in different books and literature but these are, as a rule, fully explained within the texts concerned.