antenna-theory.com

[ep.robotics]

I have an array of up to 40 transmitters (2.4 GHz zigbee TDMA) with randomly oriented rubber duck omni antennas, located within an angular sector of 80 degrees vertical, 60 degrees horizontal of a base transceiver antenna mounted 22 ft above ground.

Transmitter antenna directions cannot be controlled, and can re-orient slowly over the course of several hours.

Base antenna is a single patch A2408NJ-DP from Pro-Soft (60 deg x 60-deg), but is marginal.

It has been suggested that we use four of these antennas in an array, two vertical pointed 30 degrees apart, and two horizontal pointed 20 degrees apart, with a four-way splitter and amplifier.

Any suggestions would be greatly appreciated, as I have very little antenna experience.

Thank you,
David

[bigSteve]

It's not clear to me what you are trying to do. What is the objective?

The array doesn't make sense - adding a splitter and combiner is somewhat expensive, adds a lot of hassle....I wouldn't entertain that suggestion. Why not just build a simpler antenna that has better performance? An array (as you described it, with an adder) is the same as a larger antenna. I'd recommend (and you'd save money) just spending your splitter/combiner money on a better antenna (or just design it yourself and the cost is negligible)

[ep.robotics]

We are trying to read sensor data from wireless transducers, transmitting at 8Hz using TDMA. The sensor data is used to close loop on a controller which is guiding the structure, so dropping packets can be a problem.

Due to the geometry we are having trouble receiving the data consistently and are looking for guidance on a receiving antenna system. The transmitters are putting out about 25 mW; the geometry is in the first post.

In my original post I used the word "array" in the description of the transmitters. This was a bad word choice and may be misleading. It is just a bunch of transmitters attached to a structure at various points measuring stresses. We have no control over the orientation of the transmitting antennas.

My field is programming and controls, not antennas, so I am looking for help in getting reliable reception.