A simple comb generator would fill all the frequencies nicely, and is very cheap compared to an SDR transmitter. I have no idea how useful the comb waveform is

A simple comb generator would fill all the frequencies nicely, and is very cheap compared to an SDR transmitter. I have no idea how useful the comb waveform is to "break" the RNG output though. Here is one for $99, I'm sure you could DIY one for less with reduced output power: https://www.tekbox.net/test-equipment/comb-generators/tbcg1-radiating-comb-generator https://www.tekbox.net/test-equipment/comb-generators/tbcg1-...