EA4EOZ, an amateur radio electronic enthusiast: Pipe cap filters for 10GHz
Building a 10 GHz Pipe Cap Filter – VK4GHZ.com
10 GHz PIPECAP FILTER
Copper Pipe End Cap 10 GHz Bandpass Filters
#21 10GHz Pipe Cap Filter - YouTube
Copper Pipe End Cap 10 GHz Bandpass Filters
Steve on Twitter: "Today I've been experimenting with a QO-100 QRP TX strip. This included a first attempt at making a Pipe-Cap filter. Initial tests confirm it does actually tune to 2.4GHz!