ANT-418-WRT-xxx Data Sheet by Product Description 19.0 mm The WRT Series antenna is ideally suited for (0.75 ) applications such as wireless vending, security, traffic, or power equipment which require an unobtrusive, tamper-resistant antenna solution. 27.0 mm The small 27 mm radome installs through a (1.06 ) small hole on the product and is anchored by a Adhesive Ring threaded base. An adhesive foam compression Remove protective plastic before installation ring is used to resist the elements. The antenna 6.0 mm (0.24 ) also features an integral counterpoise, which M11x1.0 mm reduces the need for a proximity ground plane. Thread The antenna is suited for mounting in applications where the counterpoise will not be shielded 5.26 mm from the antenna (non-conductive or open metal (0.207 ) enclosures) installation where the counterpoise is 83.8 mm (3.30 ) within a shielded enclosure will affect the antenna performance. The antennas coax feed is available with SMA or RP-SMA terminations. Alternate coax lengths, connectors and custom colors are available for volume OEM customers. Features Low cost Unobtrusive Tamper resistant RG-174 Cable Length 216.0 mm Integral counterpoise (8.50) Indoor / outdoor Adhesive or permanent mount Electrical Specifications Center Frequency: 418MHz Recom. Freq. Range: 409426MHz VSWR: 1.9 typical at center Peak Gain: 1.3dBi Impedance: 50-ohms Oper. Temp. Range: 30 to +90C Max. Recom. Torque: 4.0 kgf-cm Electrical specifications and plots measured on 10.16 cm x 10.16 cm (4.00 x 4.00) reference ground plane Ordering Information ANT-418-WRT-RPS (with RP-SMA connector) ANT-418-WRT-SMA (with SMA connector) 1 Revised 12/9/13VSWR Graph VSWR 1.469 Reflected Power 3:1 25% 2:1 11% 1:1 0% 368MHz 418MHz 468MHz What is VSWR The Voltage Standing Wave Ratio (VSWR) is a measurement of how well an antenna is matched to a source impedance, typically 50-ohms. It is calculated by measuring the voltage wave that is headed toward the load versus the voltage wave that is reflected back from the load. A perfect match will have a VSWR of 1:1. The higher the first number, the worse the match, and the more inefficient the system. Since a perfect match cannot ever be obtained, some benchmark for performance needs to be set. In the case of antenna VSWR, this is usually 2:1. At this point, 88.9% of the energy sent to the antenna by the transmitter is radiated into free space and 11.1% is either reflected back into the source or lost as heat on the structure of the antenna. In the other direction, 88.9% of the energy recovered by the antenna is transferred into the receiver. As a side note, since the :1 is always implied, many data sheets will remove it and just display the first number. How to Read a VSWR Graph VSWR is usually displayed graphically versus frequency. The lowest point on the graph is the antennas operational center frequency. In most cases, this will be different than the designed center frequency due to fabrication tolerances. The VSWR at that point denotes how close to 50-ohms the antenna gets. Linx specifies the recommended bandwidth as the range where the typical antenna VSWR is less than 2:1. Data Sheet ANT-418-WRT-xxx 2 by