Automatic Gun Laying Turret - AGLT
Also known as "Village Inn" or "Z-equipment"

AGLT is a centimetre wave (S-Band) equipment installed in heavy bombers which also carry H2S.
Its purpose is to provide the rear gunner with data about the position of enemy fighters attacking the bomber and to assist him to train his guns and to open fire on an unseen target with an accuracy of half degree.
The AGLT also provides a warning to the whole crew, in the form of a "pipping" note injected into the intercommunication system. the frequency of the "piping" gives a crude indication of the range of the attacking fighter.
The AGLT equipment can also feed information to the Gyro Gun Sight (Mark IIC) which then predicts the approciate sighting allowance that must be made. This is usually performed by the crude method of firing tracer or by guess work. AGLT supplies among other data, the important quantity-the range of the fighter.
The gunner is given a "spott indicator" display which indicates the direction of the target and, by growing "wings," its range. An image of the display is thrown on to the plane of the gunsight graticule so that the gunner may sight on to the spot just as if he were sighting on to an actual aircraft in daylight. Early warning of the proximity of an attacking fighter is given to the rear gunner by the "Fish Pond" operator.

AGLT Mark I

RAF designation ARI 5559
Main items Transmitter/Receiver TR 3548
Receiver R3547 (or 3584)
Modulator type 169 (or 189)
Indicator type 217
Switch unit type 221, 226
Control unit 488
Remarks The scanner is fixed to turret and linked mechanically to the guns. Equipment uses a Gyro Gun Sight.

AGLT Mark II

RAF designation ARI 5561
Main items Transmitter/Receiver TR 3548
Receiver R3547
Remarks

AGLT Mark III

RAF designation ARI 5562
Main items Transmitter/Receiver TR 3548
Receiver R3547
Modulator type 169
Indicator type 217
Switch unit type 221
Remarks Provides continuous search and automatic change from search to lock-follow with the scanner attached to the airframe and not to the turret.

AGLT Mark IV

RAF designation ARI 5632
Main items Transmitter/Receiver TR 3604
Remarks Miniature equipment.
Working independent from the H2S equipment.

Harmonisation Equipment

RAF designation
Main items
Remarks This is an apparatus used to line up the AGLT equipment on the ground. It provides an artificial echo which allows the radar axis of the scanner to be made the same as that of the gunsight.

Liquid Lunch

RAF designation ARI 5608
Main items Receiver R3588
Remarks This is a recognition system to be carried by bombers, which reveals them as friendly aircraft to the rear gunners of other bombers carrying AGLT. The recognition will probably be provided by a lamp which lights when the beam from the AGLT scanner strikes the friendly bomber.