Due to a delay in the formulation of the exact specifications for the radio equipment, construction of the first vehicle only began on 14 June 1938. The first two vehicles were sent to Satory on 1 and 2 August 1938. After delivery the Army built in the radio sets; this process was finished for all ten vehicles in the Spring of 1939. The first vehicle used two ER29 sets; the others, conforming to a decision already made in 1936, used a combination of the ER29 and the ER26 ter; in the latter case the effort to remain inconspicuous was rather spoiled by a very prominent large horizontal radio antenna frame fitted on top of the "turret".