Antennas

In addition to chip antennas on various USB attached wireless devices, three types of external antennas are attached to various RF devices on the nodes.

WiFi Antennas

Most of the internal WiFi devices are attached to dual band, blade style omni-directional antennas shown in Figure 1. These are mounted at the end of the two rods extending at the 45 degree angle downwards from the node harness as shown in Figure 2 with the distance between the two antenna rods (i.e. two WiFi devices) of 26 inches.

These antennas have typical donut-shaped shape radiation pattern​ with an average 2 (@ 2.4 GHz) and 4 (@ 5GHz) dBi of gain.

Multi-standard Antennas

Number of SDR units in the grid have multi-band (i.e. multi-standard) antennas​ covering most of the WiFi and 4G bands. They are mounted on the square plate about 12 inches apart (in horizontal plane) as shown in Figure 4.

Image(MountingPlate.png, width=400)

Electronically Steerable Antennas

4 nodes with USRP X310 devices in addition to standard antennas (WiFI for two internal devices and multi-standard paddle antennas) are equipped with an electronic selection device and a steerable antenna.

The block of RF switches can be directly configured as follows if the standard available configurations are not sufficient (blanks indicate the particular switch state does not matter).

Configuration	SW 1	SW 2	SW 3	SW 4
Node Wifi 0 → standard antenna	RF 1
Node Wifi 0 → directional (FCI antenna)	RF 2	RF 1
USRP RF A → standard antenna			RF 1
USRP RF A → directional (FCI antenna)		RF 2	RF 2
USRP RF B → standard antenna				RF 1
USRP RF B → omni (FCI antenna)				RF 2

Antenna Switching Hardware

Directional Antenna AM Service is used to manage the antenna switchbox and select which antenna is connected to respective wireless device.