Side-by-side
GS-20 Underground Sensor vs GS-21 Underground Sensor
Spec comparison for two products on Aviation Souk. Both compete in perimeter-security.

perimeter-security
GS-20 Underground Sensor
by vortex-systems
Buried seismic and magnetometer intrusion sensor with 5-Watt VHF reporting up to 35 miles line-of-sight

perimeter-security
GS-21 Underground Sensor
by vortex-systems
Buried UGS with external seismic line-string support for extended pedestrian detection along a perimeter
| Cost of ownership | GS-20 Underground Sensor | GS-21 Underground Sensor |
|---|---|---|
| Price tier | — | — |
| Lead time (weeks) | ?–? | ?–? |
| Delivery | — | — |
| Install | — | — |
| GCC airports deployed | 0 | 0 |
| Certifications | 0 | 0 |
Specs
Technical specifications.
| Spec | GS-20 Underground Sensor | GS-21 Underground Sensor |
|---|---|---|
| Sensing modalities | Internal seismic (pedestrian) + internal magnetometer (vehicle presence and travel direction) | External seismic line strings (pedestrian) + internal magnetic sensor (vehicle presence and travel direction) |
| External sensor inputs | PIR and contact-closure via configurable external connector | PIR (pedestrian/vehicle presence + travel direction) and contact-closure |
| Sensor fusion | Up to 5 sensors | — |
| Radio | Built-in 5 W VHF, programmable RF output power, strong foliage penetration | Built-in 5 W VHF, strong foliage penetration |
| Radio range | Up to 35 miles line-of-sight | Up to 35 miles line-of-sight |
| Alarm codes | Up to 15 unique | — |
| Sensor address range | 1-9999 | — |
| Power | 8-20 VDC | — |
| Battery life | 1+ year (deployment 3 months to 1 year or longer depending on configuration) | 1+ year |
| Dimensions | 6.5 x 3 x 3 in | — |
| Enclosure | Watertight, corrosion-proof fiberglass-reinforced polyester with silicone foam gasket | — |
| Deployment | Buried (antenna only above ground) or above-ground | — |
| Output | Mechanical relay to trigger external devices (cameras, lights, sirens) | Mechanical relay to trigger external devices (cameras, lights, sirens) |
| Security | Internal tamper switch | Tamper switch |
| Timing | Real-time clock; programmable self-test messages and scheduled access windows | Real-time clock; programmable self-test messages and scheduled access windows |
| Networking | Stand-alone or networked; Coyote/Cub relay mode; compatible with legacy Vortex and Monitron systems | — |
| Compatibility | — | Legacy Vortex and Monitron systems |
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