O-R

O

OM: Abbreviation for "old man," an old radiotelegraph abbreviation for any radio operator (presumed to be male); now used to refer to any male radio operator or announcer.

Omnidirectional antenna: An antenna that transmits and receives equally well in all directions. 

Open repeater: A repeater station that can be used by anybody; a carrier on its input frequency will automatically be retransmitted on its output frequency. 

Opening: When propagation is possible between two stations on the same frequency.

Out: Spoken at the end of a transmission to indicate that you have made your last transmission and that you expect no response.

Output frequency: The frequency on which a repeater station will retransmit signals it hears on its input frequency. 

Over: Spoken at the end of a transmission to indicate to the other station that it is their turn to transmit. 

Overloading: When strong signals in a frequency range interfere with proper operation of a receiver, creating false "ghost signals" on various frequencies in the frequency range.

P

Parasitics: Oscillations in a transmitter on frequencies other than the desired one; these can produce spurious signals from the transmitter.

Part 15: The section of the FCC's rules that permits operation of low power transmitting devices without a license.

Pass: The period during which signals from an orbiting satellite can be heard at a ground location.

Passband tuning: A receiver circuit that permits adjusting the bandpass for best reception under different interference conditions.

Patch: A connection between a two-way radio unit and the public telephone system.

Path: The route taken by a signal from the transmitting station to the receiving station.

Phase locked loop: A circuit that can generate a wide range of frequencies in discrete steps such as 10 Hz.

Phase modulation: Similar to FM, this modulation technique varies the carrier frequency of a transmitter in accordance with the strength and frequency of the modulating signal.

Phone: Radiotelephone operation.

Phonetic alphabet: A standard set of words used to represent letters of the alphabet.

Picket fencing: A fluttering sound heard on a FM signal from a station on a moving vehicle, such as an automobile.

Ping: Brief reception of a radio signal via meteor scatter propagation.

PLL: Abbreviation for phase locked loop.

PM: Abbreviation for phase modulation. 

Polarization: Whether an antenna transmits or receives maximum radio energy in the horizontal or vertical plane.

Preamp: A receiving circuit that gives extra amplification to weak signals but at the cost of additional background noise and possible distortion. 

Preselector: A circuit that tunes a receiver's signal amplifying circuitry for maximum sensitivity on a desired frequency range. 

Priority channel: A channel a scanner will immediately switch to when a signal is present.

Product detector: A receiver circuit consisting of a beat frequency oscillator and additional circuitry for enhanced reception of SSB signals.

Propagation: The process of how a radio signal travels from a transmitting station to a receiving station.

Pulse modulation: A modulation method in which the timing, amplitude, and/or spacing of pulses of a transmitter's carrier are varied in order to convey information.

Q

Quad: A directional antenna consisting of two one-wavelength "squares" of wire placed a quarter-wavelength apart.

QRL: Radiotelegraph abbreviation meaning "this frequency is busy."

QRM: Radiotelegraph abbreviation meaning "interference."

QRN: Radiotelegraph abbreviation meaning "static."

QRO: Radiotelegraph abbreviation meaning "increase transmitter power."

QRP: Radiotelegraph abbreviation meaning "reduce transmitter power."

QRS: Radiotelegraph abbreviation meaning "send more slowly."

QRT: Radiotelegraph abbreviation meaning "stop transmitting."

QRU: Radiotelegraph abbreviation meaning "I have no messages for you."

QRV: Radiotelegraph abbreviation meaning "I am ready to communicate."

QRX: Radiotelegraph abbreviation meaning "wait."

QRZ: Radiotelegraph abbreviation meaning "who is calling me?" It is also used to solicit the next contact in a series of contacts.

QSL: Radiotelegraph abbreviation for "I confirm," it refers to a card or letter confirming that a contact did take place between two stations or that a listener did indeed hear a certain station.

QSO: Radiotelegraph abbreviation for a contact between two or more stations. 

QSY: Radiotelegraph abbreviation for "change frequency."

QST: Radiotelegraph abbreviation for a transmission directed to all ham radio operators, it is also the name of the ARRL's monthly magazine.

QTH: Radiotelegraph abbreviation for a station's location.

R

Radioteletype: A mode that uses FSK to form letters, numbers, and special characters for display on a printer or video monitor. 

Ragchew: Slang for an informal conversation via radio.

Real time: Communications that are taking place with no perceptible delay.

Receiver incremental tuning: A circuit that allows tuning between increment steps in a receiver using frequency synthesis.

Reception report: A letter written to a radio station supplying details about a station's signal and the programming heard in order to solicit a QSL from the station.

Repeater: A radio station that receives stations on a certain frequency and simultaneously retransmits them on another frequency.

Resonant frequency: The frequency at which an antenna radiates or receives with maximum efficiency.

Rig: The main items of equipment used at a radio station.

RIT: Abbreviation for receiver incremental tuning.

RF gain: A control used to continuously vary the sensitivity of a receiver.

RST: A code used by ham radio operators to indicate a station's readability, signal strength, and tone of its Morse code signals.

RTTY: Abbreviation for radioteletype. 

Rubber ducky: Slang for a shortened flexible antenna used with hand-held scanners and transceivers.