The 13 element LFA RPOL antennas polarity is rotated using simple and inexpensive TV rotators. The control of these polarity rotators must be sync’d.
Bill Ockert, ND0B built this RPOL controller.
The controller uses a CLICK PLC to control both rotators in a syncronized fashion.
The software is written in C# and has a really cool feature. You can select an option to do a “Noise Scan” this will rotate the polarity of the antennas a full 360 degrees and show graphically the lowest noise angles. This really comes in handy in a a very noisy urban environment.
Notice that the lowest noise is at 0 degrees “H” pol and that +90 is lower than -90 degrees. This tells us for this particular Az/El of the antenna, use the “+” side of the antenna polarity rotation.
See KK6FAH for additiona information.
For more information on the RPOL controller, contact Bill Ockert, ND0B