Here is a  useful waveguide adapter made for the US military "L band",  WR-650 (1.1-1.8 GHz) to N female, cover flange,  high quality, good condition. This unit is in pretty good shape, paint a little chip from use. Handy for antenna testing among other things! Hard to find adapters for big waveguide, this one covers the radio astronomy band at 1.42 GHz and makes a nice source antenna for testing your designs!  Have fun!