Refurbishment of the HUTRAD system

The lower frequency system of the legacy airborne HUTRAD radiometer was refurbished successfully for the CIMR Arctic Airborne Campaign (CIMREx). The refurbished system with dual-polarization 6.8 GHz, 10.65, and 18.7 GHz receivers is compatible with the widely used DHC-6 Twin Otter aircraft and with the Arctic conditions. The refurbished system has approximately the same performance as the original system developed in the mid-1990s, with the exception of wider antenna beams. Due to schedule and budgetary constraints, as much of the original system was maintained as possible. However, each of the three receivers has now an integrated antenna and is built into an identical (commercial) housing. Therefore, it is possible to use only a subset of the whole receiver ensemble if needed. Also, one or more of these original three receivers can be replaced with another receiver that has a different frequency, for example. The adopted modular concept makes the system a versatile tool for cryosphere research.