Cryogenic Receiver with Superconducting Filter

We have developed small cryogenic receiver with superconducting dual band pass filter. This superconducting filter passes thru only protect bands of both 1.4 GHz and 1.6 GHz for radio astronomy. Also L-band is useful band for mobile telephone. Therefore, L-band observation by the radio telescope is difficult for strong RFI of mobile telephone signal. We report a RFI test with the superconducting filter. The RFI test was experimented in urban area, suburban area, and mountain area in north Thailand. We experimented with the use of horn antenna and radio telescope antenna. We demonstrated an effectiveness of superconducting filter for countermeasure against RFI.