In the commercial world of broadcasting, there is a hybrid filter used called a mask filter. The mask filter is two -90 degree hybrids, a dummy load, and a pair of bandpass cavities between them. They suppress sidebands and keep the TV transmitter's radiation within the 6MHz channel.
Has anyone heard of a similar concept used for filtering amateur repeaters? -- Kris Kirby, KE4AHR Disinformation Analyst
