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Hermes Sensor Unit

Technical Information

Catalogue No: C0345
Category: Surveillance/Acoustics
Object Type: Sensor/Transducer
Object Name: Hermes Sensor Unit
Part No: 4-242 DL14654
Serial No: 085/92
Manufacturer: GEC Avionics
Division: Unknown
Year of Manufacture: circa 1985
Dimensions: Width (mm): 135
Height (mm): 315
Depth (mm): 77
Weight (g): 2,327
Location: Rack RAA06 [Main Store]

GEC Avionics Limited
Hermes Sensor Unit
Part 4-242 DL14654
Ser 085/92
E.B.L.R Apr 92
Alkaline Duracell
18 Volts
2-242 DG 15042 Iss. C
19 December 1985
Duracell Batteries Limited
Caution: Do not destroy in fire
Caution: This battery contains an auto-resetting thermal overload switch


This is a seismic sensor unit with settings for the detection of various types of vehicle or personnel. It connects to the related Monitor Unit via a wireless link using one of the related Aerials. The battery module that fits in the unit's top compartment allows it to run for many days, depending on the battery type.

The carry-bag can hold five of these sensor units, though the archive only has one.

The "E.B.L.R. APR 92" mark indicates that it was serviced at Rochester in 1992. The battery considerably pre-dates this.

Hermes is a family of VHF radio linked equipment using both seismic and passive infra-red sensors to detect vehicles and men, giving clear indication of classification, direction and numbers. The hand held monitor can simultaneously display the information from a group of up to 10 sensors and can respond to up to 80 sensors in groups of ten. Relay units are provided to enhance the range between sensor and monitor. The equipment was made at Borehamwood (Manufacturer's code: K0978) but was maintained by the Aviation Service and Repair Division at Rochester.

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