Radar Jargon

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Radar Jargon - 1

These pages are not intended to be a treatise on radar techniques! Aimed at explaining some of the jargon they are more like a dictionary than an encyclopedia; acronyms will be spelt out, techniques and terms will be briefly explained. For more information get the books out and RTFM!

Ace d' Base

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


Automatic Frequency Control


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


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)


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


US built search radar.


US built height finding radar. AKA "Nodding Horror"


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


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


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!)


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


Beat Frequency Oscillator


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.


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


Enemy target

Call Sign

Name of radar site or the fighter interceptor 


Constant False Alarm Rate


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


Circular Polarisation


Carrier Insertion Oscillator


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



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 linear Polarisation


Cathode Ray Tube


Continuous wave


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


See Ana-Prop


Returns, paints


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


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


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


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.


A radar antenna


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


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


The ground component of an SSR system.


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.


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


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


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


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.


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.


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

Land Line

The telephone


British air defence radar system


A circuit connecting two points

Marconi S-259

An air transportable radar system


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.


British civil ATC application of "Linesman" air defence system


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


Master Radar Station, the successor to "Rotor"


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


Moving Target Indication.

Nodding Horror

AN/FPS-6 or HF200 Height finder radar


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


Over The Horizon


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


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


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


Plan Position Indicator


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


Pulse Repetition Time - See PRF

Pulse Width

The duration of a pulse from rise time to drop time


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. 


RAdio Detection And Ranging


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


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.


The appearance of jamming on a radar display


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


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


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

Royal Air Force

See R.A.F.


Radio Frequency

RTB Return To Base


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


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


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


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


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


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


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.


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


The enemy, objects of interest on a radar display


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


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


Unserviceable, not working


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


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


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


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Updated 08/08/2009

Constructed by Dick Barrett
ęCopyright 2000 - 2009 Dick Barrett
The right of Dick Barrett to be identified as author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.