Radar, AA, No4 Mk6, old MZPI Antenna
Radar, AA, No4 Mk6, new MZPI Antenna
Purpose
To provide early warning or putting-on data to fire control equipments Radar, AA, No3, Mks1,2 and 7.
History
An initial order for 150 was placed but no deliveries were made by the end of the war. Canadian manufacture and was the mainstay of British Army radar for many years after the war
Description
Mobile medium range microwave radar unit in a four wheeled trailer. the aerial folds flat on the roof for travelleing. The putting-on facility can be increased by the incorporation of a British pattern adjacent display unit which feeds data to a remote gunsight.
Presentation Unit
Plan position indicator (PPI) of targets on 9" CRT to optional ranges of 40,000yds,
80,000yds and 120,000yds.
'A' type scan on a 5" CRT for monitoring.
Adjacent display (AD) plan position indication of targets on a remote consol.
Antenna System
Continuously rotating array consisting of two stacks of slotted waveguide radiators arranged and fed to permit selection of one of three beams either manually or in an automatic sequence. Waveguide feed with a common T and R system using soft rhumbatron. The aerial array is motor driven at 15rpm or 18rpm dependant upon power supply frequency
| Weight | 19,000 lbs approx |
| Height | operational 13'10.5" |
| travelling 11'5" | |
| Length | operational 17'2.5" |
| travelling 21'8" | |
| Width | operational 8'9" |
| travelling 8'9" | |
| Wheelbase | 11'6" |
| Turning circle | 60'0" inc tow veh' |
| Ground clearance | 16" |
| Wading depth | 5' still water |
| 5' + 1'6" wave | |
| Bridge class | 9 |
| Tyre size | 7.50-20 / 34x7 |
| Tyre pressures | 65 psi front,75 rear |
| Braking system | Warner electric with handbrake |
| Towing vehicle | HAA tractor |
| Operational wavelength | 2,850Mc/s |
| I.F. freq | 30Mc/s |
| Receiver bandwidth | 3Mc/s at -6dB |
| Tx power output | 600kW |
| Tx pulse width | 1 us |
| Recurrence freq | 660 c/s |
| Detection accuracy | range +/- 1000yds |
| azimuth +/- 2deg | |
| elevation 5,000' at 40,000yds | |
| Detection range | 120,000yds |
| Target discrimination range | 500yds on 40,000yd sweep |
| Target discrimination azimuth | 5deg |
| Data Transmission Range & azimuth | by magslips |
| Data Transmission Elevation | by telephone |
Power Supplies
230V ac 50-60c/s, single phase.
Consumption : 10 kVA
Normally supplied by a skid mounted caterpillar diesel (D311)
60c/s - 22.2 kVA - 20 kW - 0.9 PF
50c/s - 16.6 kVA - 15 kW - 0.9 PF
Operators
Radar : 2
Plotting : 1
AD : 1
Anti-Jamming
Interference suppressor is incorporated in the receiving system which discriminates between unwanted and wanted signals on the basis of amplitude.
I.F.F.
Provision is made for the fitting of IFF when provided.
Special Features
The set is of tropicalized construction throughout. An air dryer is fitted into the waveguide system. To minimize ground clutter provision is made to tilt the aerial array by means of wedges.
Versions
No4 Mk6/1
Old MZPI antenna system.Early versions seem to be have built on the shorter No4 Mk1 style trailer.
No4 Mk6/2
New MZPI antenna system.
References and Sources
- EMER, Telecommunications, 0 230, Equipment Radar, AA,No4 Mk6/2, Data Summary, Dec 1952.
- R.E.M.E. Museum Archives, Arborfield.
More No4 Mk6 pictures
No4 Mk6 radar
A surviving No4 Mk6 radar somewhere in the UK
A surviving No4 Mk6 radar somewhere in the UK
An internal photo of the No4 Mk6 radar