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WCAU Used Shortwave in Philadelphia

Between the Wars, the Station Launched a Shortwave Operation Under Call Sign W3XAU

This is the third in an occasional series about shortwave broadcasting stations in the United States and its territories, published in cooperation with the National Association of Shortwave Broadcasters. Some stations are almost forgotten, others can still be heard today.

During the radio era before World War II, many broadcasters in the United States and abroad sought to establish shortwave relay stations in an endeavor to give them wider coverage.

At the time, television was more a concept than market reality, and FM radio as we know it was still in the future. The medium-wave band was not overcrowded, though the medium-wave signal generally gave only local coverage. However, shortwave transmissions could give wide-area coverage within the country and even international coverage on a wider scale.

‘The Spirit of WCAU,’ a pamphlet from the 1930s, courtesy of Charles A. Higgins. Many medium-wave stations in the United States established shortwave relay transmitters during the late 1920s and 1930s to carry programming to distant listeners. In fact, some radio historians estimate that there have been somewhere around 100 shortwave stations on the air in the United States during the past 80 years; probably more than half of these were active in the pre-war era.

One of the shortwave stations that enjoyed a high reputation during the early years was in Philadelphia. Engineers at AM WCAU constructed the transmitter for this collocated shortwave station, which was licensed by the Federal Radio Commission under the experimental call sign W3XAU.


A casual glance would seem to indicate that this was an amateur radio station, but that is not the case. The X in a prewar call sign indicated an experimental station, either amateur or professional. Station W3XAU was a professional station, relaying the programming from medium-wave WCAU.

It was in 1922 that the Philadelphia Radiophone Company had launched medium-wave station WCAU as a small operation in the back room of a radio shop in Philadelphia. Ten years later, following a couple of intermediate migrations, a professionally built studio complex became the new home for WCAU; this was the first building in the United States constructed specifically as a radio station. The modern facility was located at 1622 Chestnut Street.

The WCAU-W3XAU transmitter building at Newtown Square, Pa., around 1930, from a QSL postcard. At the same time, the WCAU engineering staff installed a new 50 kW medium-wave transmitter in a new building at Newtown Square. The initial broadcast from this grand new WCAU was Sept. 19, 1932. At this stage William Paley owned WCAU and looked upon it as the flagship station for his fledgling CBS network.

Early in 1930, the staff installed a small, locally made 1 kW shortwave transmitter with the call sign W3XAU with the regular medium-wave unit in Philadelphia. WCAU personnel believe that this was the first license issued by the FCC for an international shortwave broadcast station as a commercial operation.

The main purposes for adding a shortwave transmitter as a slave relay of the medium-wave unit were to extend the station’s coverage area, even internationally, and to provide a program service that could be relayed locally by distant medium-wave stations. Management saw this additional programming coverage as an incentive for advertisers to purchase time on such stations.

Two years after the Newtown Square facility was inaugurated, engineers rebuilt the 1 kW shortwave transmitter and installed it alongside the huge 50 kW medium-wave unit. Four years later, they re-built the transmitter to 10 kW capacity and two V-type antennas were erected for coverage into Europe and South America.

WCAU became even more ambitious for an international outreach with the erection in late 1938 and early 1939 of two large curtain antennas for coverage of those two continents. At the same time, the station made a request to federal licensing authorities for 50 kW operation on shortwave. On several occasions in the late 1930s and early 1940s, they had already submitted similar applications, but on each occasion the request was denied.


With the threat of war spreading in Europe in 1939, the FCC took a hard look at the international shortwave scene in the United States and issued a set of new rules.

WCAU studio building at 1622 Chestnut Street in Philadelphia, seen on a QSL postcard postmarked 1935. The edict, issued on May 23, 1939, required that shortwave call signs should be regularized; power should be increased to 50 kW; and directional antennas should be installed.

The ruling provided time for consideration and negotiation regarding desired call letters. Initially, the first new call sign chosen to replace W3XAU was WCAI. This call sign for the shortwave outlet proved temporary.

According to information in Time magazine, FCC news releases and several other sources, “WCAI” was in use for a little less than two weeks beginning in mid-August of 1939.

The FCC subsequently ruled that all call sign changes for the shortwave stations should become effective on Sept. 1. However, some stations introduced their new call signs prematurely, and at least a couple were tardy. As far as W3XAU was concerned, the station changed the call from WCAI to WCAB on Aug. 26, one week before the official date.

No known meanings have been attached to the call signs WCAI or WCAB; it is probable that these were vacant call signs still available in the WCA series, thus associating the new shortwave call with the parent station WCAU. As for the directional antennas, they were in place. And the power increase to 50 kW? They had already applied on several occasions previously and been denied.

However, there was another factor to consider: CBS had a large new shortwave station under construction at Brentwood on Long Island.

Just prior to World War II, CBS owned and operated two shortwave stations, the 10 kW W3XAU in Pennsylvania and another 10 kW unit, W2XE in Wayne, N.J. However, with the escalation of the conflict, CBS was involved with two large additional shortwave stations; Brentwood as well as Delano in California.

Shortwave transmitter W3XAU in the 1930s, co-sited with AM-MW transmitter at Newtown Square, on another QSL card from W3XAU. Initially, the concept was for WCAB in Philadelphia to supplement Brentwood. However, in view of the FCC power restriction, CBS finally decided to close the Pennsylvania station in favor of the large new facility under development on Long Island.

New Year’s Eve

Programming from the Philadelphia shortwave station initially was a tandem relay from medium-wave WCAU, though separate identification announcements were given live over the air.

However, when the station became a genuine international broadcaster, much of the scheduling specifically was prepared programming for the target areas, Europe and Latin America. Programming in foreign languages was taken on relay from W2XE in Wayne, and programming in English was also taken live from the CBS national network. This shortwave station was heard frequently throughout the Americas, in Europe and in the South Pacific.

The 50 kW shortwave transmitter WCRC at Brentwood was inaugurated on Jan. 1, 1941. Just one year later, the 10 kW W3XAU-WCAI-WCAB at Newtown Square was switched off. This nostalgic event occurred at midnight on Dec. 31, 1941.

However, that is not the end of the story. The large new international shortwave station at Brentwood was taken into service with OWI-VOA (Office of War Information & Voice of America) programming less than two months later, on Feb. 24, 1942 and the 10 kW unit in Philadelphia was packed up and sent over to England for use by the BBC in London.

How interesting it would be to find out what happened to this famous American transmitter while it was in service over there.

Dr. Adrian M. Peterson is a board member of the National Association of Shortwave Broadcasters. He was born in South Australia in 1931; since 1944 he has written several thousand articles on radio history, which have been published in 25 languages. He is advisor to the program “Wavescan” and coordinator of international relations for Adventist World Radio.