Designer Josef Zenisek substantially participated in the development of the Czechoslovak communication equipment. Being inspired by German and Anglo-American UHV communication means, he designed many pieces of apparatus for the Czechoslovak Signal Corps in Prague-Kbely. Next apparatus was the legendary small radio relay (directional) “ŽENÍŠEK” station which was introduced into armament of Signal Corps as RDM-61. At first, they produced 10 prototypes marked RD-471 in Kbely. In the middle of the fiftieth, it was introduced into armament of Czechoslovak Army and replaced the trophy SEG 2 T “ELSTER”; altogether, they produced about 100 stations.