Ace d' Base

At the top of the profession, no one on the site can better this fellow!

AFC

Automatic Frequency Control

Agile

A radar system capable of rapidly jumping from one frequency to another. Used to defeat spot jamming.

Airway

Controlled airspace in the form of a road in the sky. In the UK the airway is usually identified by a colour and a number ie Red 01, Green 15 etc. (A rich source of targets)

AMES

Air Ministry Experimental Station, as in AMES Type 80 and so on.

US built search radar.

AN/FPS-6

US built height finding radar. AKA "Nodding Horror"

AN/xxx-xx

US military equipment designation - see next glossary page for full details

Ana-Prop

Anomalous Propagation of radar signals that causes ground returns and targets to be seen out to greater than normal distances - or not at all!. Often caused by refraction of the signal in the atmosphere in regions of high pressure

Angels

Height in thousands of feet, ie Angels 15 = 15,000 feet. (This term was also used in the early days of radar to describe returns caused by large flocks of birds. In those days they didn't know what caused these returns, so if they weren't aircraft they must be angels!)

Azication

Remote pointing of a nodding height-finder in the direction of the target

Barrage Jamming

Broad band noise transmission directed by a jammer at a radar with the intention of rendering the radar ineffective. Usually used against Agile radars

BFO

Beat Frequency Oscillator

Blanking

Suppression of video signals on a display screen during the fly back stage of the trace, suppression of signals at trace origin to remove close in permanent echoes.

Blip

Movie term for a return - never used by professionals

Blip Dip

US term for a Scope Dope

Blind Spot

Area where targets may not be detected due to screening by terrain

Blind Zone

See Blind Spot

Blue Yeoman

Code name for the British Type 85 air defence search radar

Bogie

Enemy target

Call Sign

Name of radar site or the fighter interceptor 

CFAR

Constant False Alarm Rate

Chaff

Lengths of aluminium foil or fine wire dropped by an aircraft to produce many confusing targets. Also known as "Window"

Circ-Pol

Circular Polarisation

CIO

Carrier Insertion Oscillator

Clutter

Permanent returns on radar displays caused by mountains, pylons, buildings etc.

Comms

Communications

Cone of silence

Antenna systems are usually designed to radiate towards the horizon, not vertically. Such designs can cause a region of attenuated signal in a cone radiating up from the antenna. 

Cross-Pol

Cross linear Polarisation

CRT

Cathode Ray Tube

CW

Continuous wave

Dome

A ball shaped enclosure used to protect a radar antenna from the elements. Often called "Golf Balls" by the media

Duty Cycle

Pulse Width x PRF

Ducting

See Ana-Prop

Echo

Returns, paints

FAR

False Alarm Rate

Fish Pond

A large CRT display approximately  1 Metre in diameter mounted so that its face was horizontal. Several people could gather around the display

Fruit

Unwanted SSR returns received as a result of a transponder reply to another interrogator.

Garbling

False codes displayed when aircraft are close enough for their SSR responses to overlap.

Golf Ball

A newspaper name for a Radome. Also a form of print head in a teleprinter

Grass

How noise appears when viewed on an oscilloscope, a spectrum analyser or Type 'A' radar display

Green Garlic

Code name for the British Type 80 air defence search radar

Ground Returns

Permanent returns on radar displays caused by mountains, pylons, buildings etc.

Head

A radar antenna

Hostile

A non-friendly target Designated H-xxx on the plotting board, the xxx indicating the track or raid number

HSA

The High Speed Aerial used in the British RX12874 anti jamming equipment

Interrogator

The ground component of an SSR system.

JAFAD

Just Another Flippin' Air Defence (technician) (clean version! - Ed.). Generic term used to describe Air Defence technicians (AD's) whose responsibilities, range of postings, promotion prospects and career paths have been seriously eroded in the years since the split of the ground radar trade in to Air Fields and Air Defence and the ending of the Cold War. The angst of JAFAD's  is legendary in the Royal Air Force.

Jammer

An aircraft that transmits  an interfering transmission designed to confuse the operator or render a radar system inoperable

Jamming

Interference on a radar display or the transmission of signals designed to interfere with the radar's operation or to confuse the operator

Kaput

Unserviceable, broken. (I believe this word is of German origin)

Klystron

An amplifier valve. An electron stream is direct through a series of cavities causing each cavity to resonate. The RF input is fed into the first cavity causing velocity modulation of the electron stream . The successive resonating cavities amplify the velocity modulation, resulting in a signal gain. The output is taken from the final cavity. A gain of up to 40 dB can be achieved.

L1

The central control station for the British  "Linesman" air defence system. It was located at RAF West Drayton in Middlesex, England, to the west of London.

L-band

A band of frequencies in the 23 cm or 1.5 GHz region

Land Line

The telephone

Linesman

British air defence radar system

Link

A circuit connecting two points

Marconi S-259

An air transportable radar system

Magnetron

A radar transmitter valve. Electrons emitted from a cathode follow spiral paths to the anode through a perpendicular magnetic field. The anode contains a number of slotted cavities which resonate as the electrons pass the slot. The magnetron is designed such that the power derived from the oscillations from each cavity slot combine to produce an RF signal. The RF energy is coupled by a stub to the wave guide system.

Mediator

British civil ATC application of "Linesman" air defence system

MBS

Main Bang Suppression. A pulse that suppresses the display video for the duration of the transmission pulse.

MRS

Master Radar Station, the successor to "Rotor"

MTU

Master Trigger Unit. Used to synchronise all the radar transmitters at a particular site

MTI 

Moving Target Indication.

Nodding Horror

AN/FPS-6 or HF200 Height finder radar

Noise

An undesired component of an electronic system. In radar systems the received RF energy must be at a greater level than the noise level of the system to be discernible

Noise Jamming

Broad band RF noise that can mask radar targets.

Noise Spokes

The appearance of noise on particular bearings on a PPI display resembling the spokes on a bicycle wheel

OTH

Over The Horizon

Paint

A radar return or echo (hardly ever called a  Blip - this is usually only used by hams and movie makers!)

PDS

A name given to the RX12874 anti jamming equipment in the British "Linesman" air defence system meaning Passive Defence System or Passive Detection System

PDU

Radar Photographic Development Unit. A system that recorded, developed, fixed and dried photographic pictures of a radar PPI and then projected the image on to a large plotting table. Found in the R3 building at MRS's

PPI

Plan Position Indicator

PRF

Pulse Repetition Frequency. The frequency of pulse transmissions in a pulsed radar transmitter 

PRT 

Pulse Repetition Time - See PRF

Pulse Width

The duration of a pulse from rise time to drop time

PVR

Premature Voluntary Retirement - Early termination of engagement by RAF personnel. A term well known to JAFAD's (see above).

R1, R2, R3, R4 etc.

"Rotor" system buildings. Some were buried below ground, others were on the surface or partially buried. 

Radar

RAdio Detection And Ranging

Radome

A ball shaped enclosure used to protect a radar antenna from the elements

Radial Velocity

CW radar term describing the speed at which a target is heading towards or away from the radar

R.A.F.

Royal Air Force, the world's first and oldest military aviation armed force that was not a part of another armed service. The R.A.F. was formed on April 1st 1918 from the Royal Flying Corps and the Royal Naval Air Service.

Railing

The appearance of jamming on a radar display

RDF

Radio Direction Finding - the term used by Robert Watson Watt to describe the technique that came to be known as Radar

Return

The appearance of a target on a radar display, the signal returning from the target.

Rotor

British air defence system in operation during the late 40's to early 50's

Royal Air Force

See R.A.F.

RF

Radio Frequency

RX12874

The Passive Detection ECCM anti jamming equipment in the British "Linesman" air defence system

S-Band

A band of frequencies in the 10 cm or 3 GHz region

Scanner

An inaccurate name for a rotating radar antenna

Scope Dope

A radar operator, any operator, regardless of rank.
Important Note: This term does not apply to the PDS technicians on the RX12874 system!

Sector Scan

Causing the radar to sweep back and forth between two azimuth bearings rather than continuously rotating

SGC

Sensitivity Gain Control - see STC

Side Lobe

Unwanted lobes in a directional antenna

Side Lobe Jamming

A method of jamming a radar by transmitting the jamming signal only as the side lobes pass the jammer, thus confusing the operator as to the true bearing of the jammer

Spoke

The appearance of noise on particular bearings on a PPI display resembling the spokes on a bicycle wheel

Spoof

Measures used to confuse the other side by transmitting false information

Spoof Jamming

Measures used to confuse the other side by transmitting false information. In radar terms this might involve transmitting a carefully timed pulse into a radar's side lobes in an effort to produce false returns on the radar display. 

Spot Frequency

The frequency of a CW transmission

Spot Jamming

The transmission of a CW signal to jam a particular frequency

SSR

Secondary Surveillance Radar. A ground based interrogator transmitting at 1030 MHz triggers a response from an airborne transponder transmitting at 1090 MHz. The coded reply can contain (amongst other things) information about the identity and altitude of the aircraft carrying the transponder.

STC

Sensitivity Time Control, Swept Time Control. A method of varying the gain of a radar system such that signals from targets close to the radar receiver are not amplified as much as signals from further out. The gain is set to rise exponentially. Used on PPI systems to suppress near-by clutter.

Steely Blue Eyed Ace

A pilot. Pilots fly Targets, Targets produce Returns.

Sun Spoke

A spoke of noise on a radar PPI screen caused by the Sun when it is low on the horizon

Target 

The enemy, objects of interest on a radar display

Tac-Eval 

Tactical Evaluation. Several days of hell inflicted on a unit on an annual basis to see if it is ready to go to war

Trace Ace

An exceedingly gifted scope dope (Very rare!)

The Hole

An underground installation, particularly "R3" bunkers at MRS's

Theta/Phi display

The "vertical raster" operators display in the RX 12874 Passive Detection anti jamming ECCM system

Transponder

The airborne component of an SSR system.

Type 80

British air defence search radar that came into service in the early 50's and survived into the 90's. S-Band, 3 Mw (peak), antenna rotated at 4 rpm, cosecant squared radiation pattern

Type 84

British air defence search radar. This L-band radar had an excellent MTI system. The antenna rotated at 4 rpm.

Type 85

British air defence search radar. S-Band, Twelve beam volumetric scan, antenna rotated at 4 rpm

U/S

Unserviceable, not working

UKADR

United Kingdom Air Defence Region

Wave guide

Hollow rectangular, oval or round tube used to convey microwave RF energy from one point to another in a radar transmitter or receiver

Window

Lengths of aluminium foil or fine wire dropped by an aircraft to produce many confusing targets

Wood Pecker

The sound made by OTH radars when heard on an HF communications receiver

X-Band

A band of frequencies in the 3 cm or 10 GHz region