The primary function of the network relay poles is to provide the on-reef wireless network using the 900 MHz spread-spectrum radio. The poles are 6m tall and made from galvanised steel, they are self supporting and normally sit on a large sandy area within the reef lagoon although they have been deployed on reef flats. They need a flat area of around 8m by 8m.

The poles provide a stable platform for the network and so are suitable platforms for attaching sensors and other equipment that needs a stable base. They are used, for example, to mount the Vaisala weather stations.

The top of the pole contains the instrumentation and power systems. Power is provide by four 5W solar panels that fed into a power regulator and then into a small sealed battery that is housed in a small Pelican case. In a similar Pelican case is mounted the CR1000 logger and radio along with an optional inductive modem for connection to an inductive coupler. The instrument box has connections for an SDI-12 sensor string, RS232 based instruments as well as a direct RS-232 connection to the logger to allow the system to be programmed without opening the Pelican case. A small solar power navigation light is mounted at the top of the pole along with the spread-spectrum radio aerial, in this case an RFI CD1795 aerial.

The photo below shows the mounting of the two Pelican cases (one for the battery and one for the logger), the solar panels and the navigation light.

The picture below shows the boxes in place, the white cover is added to reduce the impact of UV radiation on the equipment.

Photo below of the deployed pole showing the base design with each leg being held on the substrate using two railway wheels from a small cane train (about 30Kgs each. This pole has a thermistor on one of the legs and the cable (encased in PVC pipe) can be seen running down the pole onto the right hand leg.