W-band orientation selective DEER measurements on a Gd3+/nitroxide mixed-labeled protein dimer with a dual mode cavity

► A Gd3+-nitroxide distance of 5.75 nm was determined by W-band DEER. ► A new dual mode cavity gave the required ∼700 MHz observe-pump frequency separation. ► 12 μs dipolar evolution was achieved, distances of 8 nm and above can be accessed. ► Orientation selection was resolved and analyzed.