The June 11 broadcast marked the 70th anniversary of Armstrong's first public demonstration of FM.

Steve Hemphill, WA3ZAE poses beside his homebrew work of art.

Armstrong's original building, with the call sign W2XMN, built in 1934, still stands today as a monument to the father of FM.

High above the New Jersey Palisades just north of Manhattan stands the Armstrong Tower. Total height above sea level is close to 1000 feet.

On Saturday, June 11, 2005, Steve Hemphill, WA3ZAE, had his dream come true. At 11:45 AM, with a flick of a switch, Steve returned to the air--for the first time in almost 6 decades--an FM broadcast transmitter on 42.8 MHz. This frequency was part of the original allocation for FM before broadcasters were moved to 88-108 MHz.

In commemoration of the first FM broadcast 70 years earlier by Major Edwin H. Armstrong, this special event under the call sign WA2XMN was authorized by the FCC under a Special Temporary Authority (STA). It was made possible by the efforts of Charles E Sackermann Jr, President of CSC Management, current owner of the Armstrong tower.

The transmitter, a homebrew beauty made by WA3ZAE, operated as a full bandwidth audio, +/-75 kHz deviation, with standard 75 microsecond preemphasized audio. The program content comprised a live interview of panelists along with prerecorded programming highlighting Armstrong's accomplishments. A radio version of the book Empire of the Air was also aired. The transmission concluded with the replay of the station KE2XCC's final sign-off recorded in March 1954.

Transmitting at 250 W (QRP when compared to the 50 kW used by the "Major"), the antenna was located on top of the Armstrong tower in Alpine, New Jersey, at a height of almost 1000 feet above mean sea level. Signals were received as far away as Philadelphia, with most of the reports confirming Q5 copy. The ceremony was simulcast on WFDU, 89.1 MHz and was also available via the Internet.

In addition to the program, Mike Katzdorn, KB3LFX, a collector of antique radio apparatus, put on display an original breadboard made by Armstrong. The Master Oscillator/Balanced Modulator used in 1934 during his research and testing of FM at the Empire State Building is now part of Mike's collection. Also on display were the first FM radios of the day.

A number of Amateur Radio operators were among the 125 invited guests at the ceremony. The STA will be in effect until October 2005, and there is talk of additional activity before its expiration. Also, the concept of recreating the first FM broadcast network that connected Alpine, New Jersey to Connecticut, Massachusetts and New Hampshire is under consideration for the 75th anniversary.

Three views of Armstrong's experimental breadboard station in the Empire State Building. The two right-hand photos of Armstrong's experimental station courtesy the Web site of Mike Katzdorn, KB3LFX. [Photos by the author]

More information about Armstrong's work and accomplishments can be found at Mike Katzdorn's Web site.

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