Scanned articles covering the history of FM broadcasting in the United States. Unless otherwise noted, these scans were done by John Atwood. Articles marked "*" were extracted from americanradiohistory.com scans. Listed chronologically.
Armstrong 1936 A Method of Reducing Disturbances in Radio Signaling by a System of Frequency Modulation * - From Proceedings of the IRE (Vol. 24, No. 5, May 1936), a long (52 page) article by Armstrong on his development of FM. Extensive coverage of various tests from 1933 to 1935, including experiments of multiplexing a second channel (either audio or facsimile) above the base-band signal. Very interesting reading!
Electronics 1936 High Power Frequency Modulation * - Report on Armstrong's proposal to set up a 40 KW FM station.
Electronics Fink 1939 Frequency Modulation Demonstrated * - Demonstration of Armstrong's two experimental FM stations: 42.8 MHz in Apine, N.J. and 110 MHz in Yonkers, N.Y. The 400 foot tower in Alpine still stands today and was used to host TV transmitting antennas after the fall of the World Trade Center in 2001.
Day 1939 A Receiver for Frequency Modulation - An article by J.R. Day of the Marcellus Hartley Laboratories, Columbia University (where Armstrong developed FM) on "The first published data for the construction of an f-m receiver". From the June 1939 issue of Electronics.
Electronics Fink 1939 Frequency Modulated Transmitters * - FM broadcasting moves from being a one man (Armstrong) show towards being a commercial reality. Twenty-five stations are either on the air or have construction permits. The two transmitter manufacturers are R.E.L. and General Electric.
Armstrong 1940 Evolution of Frequency Modulation - from the Dec. 1940 issue of Electrical Engineering, the journal of the American Institute of Electrical Engineers (A.I.E.E). A good overview of the growth of FM broadcasting by the inventor himself.
Walter 1940 Design Notes on a Frequency Modulation Receptor - A pre-war FM tuner, available as a kit from Meissner. From May, 1940 issue of Radio News.
Toombs 1941 The Radio Battle of 1941 FM vs AM * - From Radio News, March 1941. Investigative reporting on the battle between the entrenched AM interests and the new FM upstarts. On the AM side are the existing broadcasters, RCA, and AT&T. On the FM side are the FCC and its chairman, J.L. Fly, a new generation of broadcasters, manufactureres such as GE, Zenith, Stromberg-Carlson, etc, and, of course, Major Armstrong. This article clearly sets up the players and conflicts that will come into play when Paul Porter becomes FCC chairman and the band allocations are changed in late 1944.
Electronics 1942 FM Network * - The cover of Electronics from Feb. 1942. These stations are linked by receiving then retransmitting programs from a distant station. The noise-reduction capabilities of FM permit this. No more expensive and low-fidelity rented lines from AT&T! The stations in Massachusetts and New Hampshire are part of the Yankee Network.
Radio-Craft 1944 FM Expansion Rapid - 44 stations on the air on the old 44-49 Mc. band. These were essentially frozen due to the war-time construction freeze, but it was noted that there were 154 applications pending. All the transmitters, antennas, and listener's receivers would become obsolete with the shift to the 88-108 MHz band in 1945.
Brown 1944 FM and Its Post-War Future * - An optimistic analysis of the expansion of FM broadcasting after the war. Assumptions: existing 42-50 Mc band with possible extentions in frequency, "super-power" stations covering broad areas. The surprise move to 88-108 Mc will nuke this analysis. Note that the author is from Zenith, which fought the move to 88-108 Mc the hardest.
Electronics 1944 RTPB on FM * - The RTPB (Radio Technical Planning Board) generated recommendations to the FCC. They propose expanding the 42-50 Mc band, keeping the 75 Kc deviation, use horizontal polarization. The surprise move to 88-108 Mc ignored this.
Electronics December 1944 A Report on the FCC Frequency Allocation Hearing - (Note: go to page 92 of the magazine, page 96 of the pdf). This is a report on the hearings for docket 6651 - the 10 kc to 30,000 Mc post-war frequency allocations. The relevant part for the history of FM broadcasting is the sudden move of the FM band to 88 Mc. This change was supported by the new FCC chairman, Paul Porter, and the testimony of Dr. K.A. Norton and Dr. L.P. Wheeler who claimed that sporadic E-layer skip and tropospheric bursts would harm FM reception in the low band. This was based on studies of military communications whose data was classified. It later turned-out that this study was bogus - see the De Mars 1945 article below. Also, Paul Kesten, vice president of CBS, pushed for a "single-market plan" to restrict FM coverage to similar commercial markets as AM. This would eliminate the super-power FM stations and crimp the ability to do over-the-air networking.
The implications of this hearing are well-described in chapter 10 of Scott Wooley's recent book The Network (Ecco Press, 2016). This change in frequency allocation obsoleted over 75 million dollars of transmitting and receiving equipment, and, in fact crippled FM up through the late 1950s. There was speculation that this change was orchestrated by the NAB (National Association of Broadcasters) and its AM broadcasters, who viewed FM as potential competition. AT&T also was behind this, since they stood to loose the lucrative leased line business that enabled AM networking. See the March 1941 Radio News article above for more details. Woolley's book also describes other examples of "regulatory capture" of the FCC. The problem is that when these cases go to court, the FCC is considered, by definition, the experts in this technical area.
I did not extract and clean-up this article, since the quality of the original scan was below my quality standards, hence the direct link to the AmericanRadioHistory magazine file. If I can find a better quality scan, I will link to it.
Electronic Industries 1945 IRE Stages Largest Technical Meeting * - Summary of the Winter Technical Meeting of the Institute of Radio Engineers (IRE) on January 24 to 27, 1945. This was dominated by the controversy of moving the FM broadcast band "upstairs".
Electronic Industries 1945 Allocations Nearer * - More on the FM move "upstairs", as well as proposed television allocations. Includes tables showing units and dollars of installed FM receivers ($76 milliion) and transmitters/antennas ($1.9 million) which would be made obsolete by the move.
Electronics 1945 FCC Places FM in 88-106 Mc Band * - The move to the FM high band is now a fait accompli. 106-108 Mc was allocated to facsimile service, but this never materialized, so it later passed to commercial FM.
De Mars 1945 Discussion of the Secret FM Hearing - As described in the Dec. 1944 Electronics article above, the justification for moving the FM band from 42-50 mc to 88-106 mc was based on Prof. Norton's claim of excessive F2-layer skywave interference on the lower band. His sources were military classified, so couldn't be discussed at the public meeting. A subsequent closed-door meeting was held on March 12 and 13, 1945 to review the classified information. This quote from the introduction to the article summarizes what happened:
"One of those conclusions was that F2-layer transmission would go twice as high in frequency as had been considered possible by others. Much publicity was given to this finding as a reason for shifting FM broadcasting to 88 to 108 mc. At the Secret Hearing, it was determined that the frequency increase was not 100% but 7%. Nevertheless, the Commission suppressed this information, and continued to offer the erroneous conclusion as a reason for shifting the FM band."
The fix was in - the FCC was clearly complicit in hobbling FM broadcasting.
Allen Jr 1947 VHF and UHF Signal Ranges as Limited by Noise and Co-channel Interference * - This is the study used by the FCC to justify moving the FM band to 88-108 mc. It was originally co-authored by K.A. Norton of the Signal Corps, but Norton begged to be omitted as co-author. After looking at ground-wave coverage, it argues that sporadic-E-layer interference (i.e. "skip") is unacceptable at the low-band frequency of 50 mc. What makes this article interesting is the "discussion" by others. C.M. Jansky, E.H. Armstrong and others basically rip this study to shreds. Unfortuneately, the die had been cast and "low-band" FM was already lost.
Carnahan et al 1947 Field Intensities Beyond Line of Sight at 45.5 and 91 mc * - This paper is the results of propagation tests in 1945 of both low-band (45.5 mc) and high-band (91 mc) over a 76 mile path. The authors are from Zenith who was a strong low-band supporter. Basically, the high-band had much more variable and worse propagation, resulting in a smaller acceptable coverage area.
Electronics McKenzie 1947 FM Chain Broadcasting * - The idea of chain broadcsting or over-the-air networking is revived. The Continental Network used both leased lines (8 kc) and radio relays and other possible networks are explored. Good history of pre-war over-the-air networking.
Radio-Craft 1948 FM Station List - All the commercial FM stations on the air in early 1948 (non-commercial/educational not included). Note that Armstrong's W2XMN in Alpine, N.J. is the only one still on the "low band".