Stadelheim Transmitter was a medium wave broadcast transmitter in Munich-Stadelheim, built in 1926 in the neighbourhood of the famous Stadelheim Prison. It took up experimental operation on March 1, 1926, and full operation on April 1, 1926. As antenna, this transmitter used a t-antenna hung up on two 100-metre-high (330 ft) freestanding steel framework towers. The transmitter used a tube transmitter and a machine transmitter from the company C Lorenz AG, the company which made the Lorenz cipher machine. However, the machine transmitter had numerous technical problems.