It's the exceptions that make us what we are, not the rules.
This is the last of the NRI booklets It is the largest at 37 pages and it is jam-packed with details on those old obsolete receivers of the 1940s. It is titled "Broadcast all-wave and television super heterodyne receiver principles." It's a little hefty. All the more interesting now in the sunset of analog TV broadcasting to read about what we just lost.
This is NRI booklet 24FR-1 "Tone Control, Volume Expansion and Noise Limiting Circuits" It is not a sweeping collection of information on various radio circuits. It is actually narrowly focused on sound quality.
This is NRI Booklet 17FR-2, printed in 1939. It's titled "How Detectors Work in Sound and Television Radio receivers." It covers the fundamentals of how radio works, something that almost no laypeople understand at all. It covers concepts like demodulation, rectification, signal separation, diodes, grid-leak condensers, C-Bias Detectors, and some early heterodyne explanation. This is heavy duty and there is a lot of math.
Much like the loudspeaker booklet, 18FR-2 "How Practical Requirements Changed receiver Circuits" has a historical tone. The National radio Institute published this booklet in 1938. This was before all-solid state ADLL circuits replaced analog tuners. But even then a long series of steps had taken place to achieve the relatively high-functioning devices.
This is NRI booklet 26FR-1 "Loudspeakers and How They Work." I have written extensively about speakers in the past. Actually I wrote about them for a straight week back in 2007. This post was almost titled "The Loudspeaker (Pt 6)" Here I can add a nice addendum to that series."What two changes of energy occur in a loud speaker?"
Radio Frequency Amplifiers for Sound and Television Communication is NRI booklet 16FR-1. It was first printed in 1937. When I first began looking at these booklets I was struck by the term "radiotrician."
This is 19FR-2 Manual and Automatic Volume Controls in the seemingly endless series of National Radio Institute booklets. Amplification was a novel advance that came with electrification. This manual covers RF voltage controls, AF voltage controls and gain controls.
This is National Radio Institute booklet 20FR-3 "How Signal Currents are Kept in Correct Paths." It's another highly technical 29 page tome. Bizarrely the booklet opens with a plea for healthy eating habits. Then thankfully it segues gently into a long piece on simple condenser filters.
Peak and Band-pass RF Tuning Circuits is Booklet 22FR-2 in that massive National Radio Institute Series of Educational manuals. They are fascinating individually despite the obsolete technology. Collectively they are a history book, more so than any Triassic-period strata.
This is 5BA-1 "Practical Laboratory Training Course" in the ongoing series of National Radio Institute training booklets. This is a bit older than the other booklets, being the only one that is top bound, and also clearly dated to 1932.
The National Radio Institute claimed to have over 8,000 students in 1922. I have no definitive source for their complete catalog over the years, and thus no idea what those first students were studying. But I have concatenated a few lists of available texts from the 1930s and come up with a partial list of over 80. There were certainly more. The list begins below the Download Link.
This is 48RX in the NRI series of unknown size and proportion. It's 29 pages, and laid out similar to the last one. It's an introduction to basic accounting and book-keeping. it's no9t terribly radio-specific. But it's certain that radiotricians as the booklets call them, would need to operate like small businesses.
Recently I acquired a set of National Radio Institute booklets from the 1930s. I will be scanning them and posting them here one at a time." In 1968 Mcgraw -Hill purchased it and changed the name to NRI Schools. They ceased operations relatively recently. A Smith bio states they closed up in 1999, a learn-at-home directory gives it as March of 2002."NRI struggled under Mcgraw Hill. In the 1970s they had the foresight to offer computer courses, but Mcgraw never successfully sold their text books to other schools, their primary business. Their phase-out in the 1990s was inevitable.
They were located at 16th and N.W. U Street in Washington D.C. NRI was another learn-radio-by-mail schools. Uniquely, they publishing a magazine called the the National Radio News. E.R. Haas was the Editor. Powell Crosley wrote for the mag, Edwin Cohan of CBS, and Joseph Kauffman and members of the FRC (before the FCC). Newsletters confirm the company was operating as early as 1929. The newsleter continued to at least 1951. In 1961 they published a text book "Mathmatics for Electronics and Electricity" then in 1972 another "Servicing Electrical Appliances." "The object of the association is to cultivate fraternal relations among the alumni of the National radio Institute, to promote the welfare of each alumnus by interchange of helpful information, to foster the spirit of unity and loyalty to out alma mater, to encourage the institute in it's dissemination of radio knowledge and to promote it's interests..."The alumni included R.E. Hartzog of KFEC, John Fetzer of WEMC, K.W. Griffith KGJF, Bayard Keough of WJSV, Donnell O'Conner WBT, Polk Perdue of WAPI, Glen Gingles of KGBZ, and an unbelivably long list of others.
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