Feeds These are the feed assemblies we use. The cast-bronze parts are made by Seavey Engineering, and incorporate an orthomode transducer to handle the circular-to-rectangular conversion. They have a small DC motor to rotate the feed for polarization adjustment, and a 10-turn potentiometer for position feedback. It's not "Laboratory Quality", but since we manually re-peak and cross-pole each time we move the antenna, it's more than adequate.

The two small LNB's are for Ku-Band, and the larger ones are for C-Band. You can clearly see the the relationship between Horizontal and Vertical polarities......90°, just as it should be! There are quite a few tuning screws on both the circular and rectangular waveguide portions of the feed, and I'm sure somebody spent a lot of time tuning it. The rectangular silver boxes between the feed and the C-Band LNB's are Terrestrial Interference (Band-pass) filters. We have a very active regional airport to the East of us, and the coastline is to the South, so on one end of C-Band we get clobbered by aircraft radar altimeters, and on the other end we get hit with coastal radar. Our other 13M TIW uplink antenna is visible in the background.



Below are the feeds we use on the Patriot antennas. We standardized all our feeds to avoid having to stock so many different replacement parts. The white "can" sticking up by the strut holds the 12VDC motor used to rotate the feed, and the pot is just barely visible next to it.