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!
Building a 10 GHz Pipe Cap Filter – VK4GHZ.com
Marwyn and John's home pages
10 GHz PIPECAP FILTER
Pipe Caps Filters for Microwave Rigs - KO4BB
EA4EOZ, an amateur radio electronic enthusiast: Pipe cap filters for 10GHz