At the IPC-XIII, Davos Instruments has been successfully operating a Hickey-Frieden (HF) radiometer from Eppley Laboratory Inc. in active mode, using a slightly modified control unit Linard.
It has been found that the HF radiometer is very well suitable for active operation. While the HF-radiometer is traditionally operated in the passive mode, it has all the necessary features needed for active mode operation.
First results have been presented in the symposium of the IPC-XIII, a preprint of the proceedings-article is available here.