This is an issue of Radio News Magazine from December 1939, featuring an article on a full-range amplifier and wireless microphone. The magazine is published by Experimenter Publishing and has contributors from various fields. It is a monthly publication with illustrated features on topics related to ham and amateur radio. The issue number is 6 and it is volume 22. The magazine is in English and was published in the United States. It is available for subscription and the unit quantity is 1.