ASSA TP 40

The transponder ASSA-TP-40 uses micropower electronics offering excellent audio pick-up with low illumination power level. The ASSA-TP-40 once deploye will operate continously over 12 months on internal battery pack and much longer with external battery pack. The ASSA-TP-40 monitors perfectly through walls and is very difficult to detect.

Operation Principle:

The ASSA-TP-40 transponder is activated just prior to deployment by installing a small wire jumper link so closing a switch contact within the transponder. The device is now ready for use.

There is normally no appreciable radiation which can be detected by conventional countermeasure. The complet transponder dormats. However, on being illuminated by a low level microwave transmission originating from the ASSA radar and receiver unit, the ASSA-TP-40 superimposes audio intelligence onto the reflected signal. A special matching receiver within the radar and receiver unit enables recovery of the audio signal. The ASSA-TP-40 consumes the same amount of power in either dormant or transponding mode, typically 60 ,uA at 3 V (less then 200 uW).

The transponder illumination power required is typically 10 mW for ranges of 10 metres through one partion wall down to 10 ,uW for ranges up to 2 metres through one partion wall. Higher power levels, up to 100 mW, can be used for greater ranges. Compact Yagi aerials are used for illumniation and reception to minimise localised interference within the listening post area. The transponder has a reflection loss of -8 dB, close to theoretical maximum.

The main attractions of the ASSA TP 40 are its small size, excellent audio quality and very low power requirements so permitting many different concealment options.