More information regarding NRI can be found here: https://en.wikipedia.org/wiki/National_Radio_Institute https://people.ohio.edu/postr/bapix/NRIradio.htm National Radio Institute (NRI) was founded in Washington D.C. and became a division of McGraw-Hill. It shutdown in 2002. NRI was well-known as a correspondence school for electronic technician training. NRI also produced a line of kits such as test equipment and a simple Novice ham radio transmitter/ receiver under the NRI and Conar labels. 1937 NRI -- Radio Correspondence Course http://ncrtv.org/members-only/scanned-materials/national-radio-institute/ ... https://www.youtube.com/watch?v=_FbZBvqo5kQ