C

C
Callsign A unique identifier for each radio amateur and licensed radio station throughout the world

Capacitor : A passive electronic component composed of two conducting plates separated by a dielectric (insulating material).

Capacitive Hat : Also known as a capacity hat. A system of wires, or at VHF and above a solid metal disk, added to the top of a vertical antenna to reduce its inductance and increase its bandwidth.

Carrier Frequency : The centre frequency of a radio signal.

Cavity filter : A very narrow RF filter used to pass one single frequency, common in repeater operations where the receiver must be protected from overload by a transmitter on the same band on the same antenna tower.

Circular Polarization: A method of polarizing the antenna such that the emmitted electric field rotates around the axis of the antenna

CLOVER  : A PSK mode that allows full duplex communications.

CNDX : Abbreviation for Conditions

Coaxial Cable : Cable that has a central conductor and an outer shield as the second conductor. Known as coaxial because the cable is cylindrical and the conductors share the same central axis.

 Color Code : Coloured bands on resistors and other components that show their value.

Condenser : old name for Capacitor

Conductor : A material through which electricity flows easily.

Core : The material used in the centre of an Inductor coil.

CQ : Request for contact - specifically "calling any operator"

Cross Modulation : distortion caused by two or more carriers interfering with each other.

CTCSS : Continuous Tone-Coded Squelch System - a sub-audible tone that is frequently used on repeaters. The signal "opens" the repeater for use.

Current : The flow of electricity through a conductor - usually associated with electron movement, but current is actually the transfer of charge between atoms.

CW : Continuous wave - used in Morse code transmissions.

CW Abbreviations Used by CW operators to reduce the length of transmissions by shortening words or phrases to a 2 or three letter code.