NOAA (National Oceanographic & Atmospheric Agency)
Port Orchard, Washington

Rare fish tanks approximately 1000’ offshore required control from shore for pumps, floats and aerators.

Installation:

Cabling has proven very costly in any location associated with Salt Water Installation. Starfish and other sea life enjoy the taste of the PVC coating on most cables and cable systems must be replaced on a regular basis.

Remedy:

We offered NOAA the alternative of using wireless communication for the main control of these necessary equipments.

Problems encountered:

Due to the mass of water to transmit across, an attenuation situation occurred. Attenuation is RF Signal Loss and can be caused by such things as large bodies of water or even dew on trees, as well as many other causes. Although this is not an exact, true definition, in laymen terms, it’s somewhat like a big magnet absorbing the signal. Please keep in mind… this is laymen explanation only, for ease of non-technical explanation.

The picture below shows a Fresnel zone that must be considered with ANY installation.

As you see in the picture, the trees have interrupted the Fresnel Zone, causing attenuation. The width of the Fresnel Zone from the center line (visual line of sight) to one outside edge is dependant on both the frequency used and the distance between the 2 antennae.  The following table shows an approximate Fresnel zone size at the center. Keep in mind that the ‘diameter’ mentioned below is the total width whereas the trees are only interfering on the bottom of the fresnel zone, so in reality we anly must move the antenna up to ½ the distance from the obtrusive item (trees, water masses, hills, buildings).

Although the table states 16ft diameter which means we would need only 8’ in the lower ½  of the Fresnel zone,  we chose to raise this minimum up to allow pedestrian and vehicular traffic between these 2 ends.

Picture of the host end installation.

 This antenna is placed at about 17’ above ground and has a clear site to the remote end.

Equipment used:

We chose the 900 Prime unit as the host end controller and the 900-R as the remote end device. Each 900-R provides 3 inputs and 3 outputs to the Control end device, allowing the control of the said aerators, floats and pumps.

This installation was installed in 2006 and is currently operating.

We learned:

This installation taught us some important information for general purposes. It showed us that in an installation such as this required some custom applications. We felt that this installation showed us that there was a need for a new product that could fulfill many requirements not currently seen in most electronic designs. What it showed us was:

• 3 inputs and 3 outputs were not enough. The industries we saw required an expandable capability to allow more expansive installations.
• Normally an electronic design has a ‘timed’ output, usually fixed in Host software. In this situation,  a float, when low, would request the pump to turn on. It would need to stay on for the finite duration until the float requests the pump to turn off. This required the output to be designed as a “follower” output, one that would follow the duration of the input.

Our solution:

In 2009, we introduced the first wireless expandable follower circuitry. Each circuit board consisted of 8 inputs and 8 outputs. These were designed as one design, either end. An input on one side struck an output on the other board and visa versa. These 8 I/O boards can be daisy chained to produce a 40 input / 40 output system, which we felt was ample for most installations. This was named the 8 I/O system.