Figure 5: Randome directional antenna
Picture courtesy of Hyperlink
The first version of the BlueSniper rifle had a 12.9 dBi Yagi antenna. While that was plenty powerful, Flexilis chose a more intimidating-looking Hyperlink 14.9 dBi Randome directional antenna. This antenna can also be used for wardriving, since Bluetooth and 802.11b / g share the same frequency band (2.4Ghz). The directional antenna provides high gain (amplification) of the Bluetooth signal and is key to the rifle’s ability to operate at a long distance.
Since waving the BlueSniper around may look threatening, you may want to paint the normally-white antenna bright orange, similar to how toy guns are painted. While this won’t win you any awards for looking cool, it may help you avoid being on the receiving end of real gunfire if you use the rifle in rough neighborhoods. Just don’t use a metallic paint, since that would interfere with the Bluetooth signal.
Like many Wi-Fi antennas, the Hyperlink antenna comes with a short cable that is terminated with an N-Female type connector. However, the Gumstix computer uses a much smaller MMCX type connector, so you’ll need a short adapter cable – generally known as a “pigtail” – to successfully connect the two together.
Antenna Mounting Plate
The antenna attaches to the rifle stock via a custom-made antenna coupler, which we’ll describe shortly. But a mounting plate must be fabricated to adapt the antenna’s mounting holes to those on the coupler.
Figure 6: Antenna Mounting Plate attached to the back of the antenna
(Click image to enlarge)
Find a metal plate and cut a piece similar in size and shape to the picture – approximately 2 X 4 inches (5 x 10 cm). The plate that Flexilis used was 3/16th of an inch (~ 0.5 cm), but you can use any thickness. After cutting the plate, make sure you debur the edges so you don’t cut yourself later. The plate attaches to the antenna with four bolts and nuts or metal screws. So you’ll need to drill a total of eight holes – four to mount the antenna and four to bolt the plate to the coupler. You can also paint the plate black to give it a more finished look.