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FM Radio Turns 70

FM Radio Turns 70

Jun 11, 2005 12:00 PM, By John Landry, CSRE, and Dave Saviet

On June 11, the 70th anniversary of the first FM radio broadcast was celebrated at the site of that broadcast, in Alpine, NJ. The facility, which still stands today, was built by the inventor of FM radio, Major Edwin Howard Armstrong. A special temporary authority was granted by the FCC for the operation of a wide-band FM station, WA2XMN on 42.8MHz, the original frequency used by Armstrong.

The panel discussion, led by Judy DeAngelis, featured several historians and relatives of Armstrong’s friends and coworkers. Photo by Dave Saviet.

The broadcast commenced at noon with a panel discussion, followed by an audio documentary about Armstrong and his unusual three-armed tower. The panel featured guests Robert Brecht, Armstrong’s great nephew; Renville McMann, an Armstrong employee and later a well known radio and TV innovator; Henry Dietz, formerly of Radio Engineering Laboratories; Gilbert Houck of Houck and Bowen Engineers and a nephew of Armstrong friend and collaborator Harry Houck; Mike Katzdorn, a leading authority on Maj. Armstrong; Steve Hemphill of Solid Electronics Labs and builder of the vintage FM transmitter that was used to broadcast the ceremony live; and Charles E. Sackermann Jr. of CSC communications, the present owner of the Alpine Tower site. Jerry Minter, the former Armstrong employee and operator who signed station KE2XCC off for the final time the evening of March 6, 1954, was also in attendance. The panel was moderated by veteran New York broadcaster Judy DeAngelis.

The program was simulcast on the current FM band at 89.1 by Fairleigh Dickinson University’s radio station WFDU-FM, which rebroadcast the 42.8MHz signal transmitted from Alpine. WFDU received the signal at its Teaneck, NJ, facilities using a vintage 1940s EH Scott receiver. WFDU also streamed the broadcast online via its website.

The transmitter used for the commemorative broadcast was built by Steve Hemphill. Photo by John Landry.

After a brief introduction of the panel, DeAngelis invited questions from the audience live and over the air via e-mail. While many questions were answered by the panel members, many more could not be, because of the lack of time allotted for questions and answers during the 60-minute segment of the broadcast.

The transmitter for WA2XMN was recently hand-built with vintage parts by Steve Hemphill of Solid Electronics Labs. The 250W transmitter uses two 4-250 tubes for output. A single-element (modified Ringo) vertical antenna was mounted at the top of the 400-foot tower. The FM system used an original Armstrong type Phase-O-Tron tube. A specially modified Tivoli Audio receiver, as well as a 1940s Stromberg-Carlson console radio from the Armstrong estate was used for off-air monitoring of the broadcast. Reception range of the original FM broadcast band signal was estimated to be about 100 miles.

The transmitter building at the base of the Apline tower. Photo by Dave Saviet.

The present day users of the 42MHz band are state police and public safety agencies. Hemphill said that the STA to temporarily operate a wide-band FM station was granted only after approval was obtained from police and fire officials in four states. His inspiration to build the transmitter came from a memorial Hemphill had attended that commemorated the 50th anniversary of Armstrong’s passing.

Armstrong was a true pioneer in the development of radio. Not only was he the inventor of the regenerative detector circuit and later the Superheterodyne circuit, which revolutionized radio reception and is still in general use today, but he also developed early over-the-horizon RADAR systems and multiplexed wireless audio links. At the time of his death he was involved in a patent dispute over his FM radio invention with RCA and other radio manufacturers. His widow, Marion McInnis Armstrong continued the patent fight in court after his death and ultimately claimed victory.

The disctintive Alpine Tower today. Photo by Dave Saviet.

CSC Communications is the present owner of the Alpine Tower Company. CSC was founded by Charles H. Sackermann Sr. who realized the towers importance as a two-way radio and paging location and purchased it in the late 1950s from Columbia University, which owned the property following Armstrong’s demise. At 625 feet above sea level, the tower offers radio coverage of the New York metropolitan area that is comparable to many sites in Manhattan. Since Sept. 11, 2001, the Alpine tower has played a key role as an auxiliary site for many New York TV and FM broadcast stations and is currently considered a regional telecommunications site by local authorities. We are grateful to the Sackermann family for its hospitality and for hosting this event.

Landry is a maintenance technician at CBS Radio/Westwood One Technical Services, New York. Saviet is a broadcast operations technician at CBS Radio/Westwood One Central Control, New York.