The Rigol DSA-815TG spectrum analyzer arrived. My DIY attenuator doesn’t look pretty, but it will do the job. It uses 3x ‘Florida RF’ hybrid attenuators, 15dB @ 50Watt each. Cooling consists of a salvaged heat sink, which is too small for sure. I’ll do some tests in advance, and add a fan later. I thought of adding a switch to make the amount of attenuation selectable, but decided against it. Total costs: less than $20. Still missing: a cabinet and two N female jacks.