Waveguide feed for dish
Recently I tested the feed for VSWR as the initial results using the dish for 3cm were poor.
At the shack of Hans, PA0EHG we could not find any good return-loss for this feed and started to analyse why.
Well see for you self!
Due to the corrosion effect, the waveguide was almost short-circuited, not permitting any good return-loss. This is really Waveguide CutoFF!!
Click on the picture to enlarge