The GVD-4 will seek out and alert for the
presence of known explosives that include:

Principles of Operation
When the equipment is switched on a continuous sample of air is drawn in via the nozzle. A concentration of explosive vapour in the sampled air exceeding 1 part in 10⁹ by volume will cause the instrument to emit a high pitched tone. The frequency excursion of the tone is an approximate measure of the concentration of explosive vapour sampled. The source can be located by passing the probe across the area from which the response was obtained and listening to the variations in response. When desirable the tone can be fed through the earphone so that it is audible to the operator only. A red light, which is visible to the operator but not to the person being searched, also appears when a strong sample is obtained.

The GVD4 is a further development of an existing range of detectors designed to facilitate the searching of people, luggage, parcels etc. for hidden explosives.

The unit is powered entirely from its own 12v rechargeable battery pack which is connected to the unit by a quick-release weatherproof connector.

Controls
The GVD4 is extremely simple to operate. The unit is controlled by a single weatherproof on/off push button switch. Once activated it will automatically adjust to the surrounding environment, avoiding possible operator error. Warm up time is in the region of about ten seconds, and the emission of a low frequency tone indicates the unit is ready for use.