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"Wavescan" is a weekly program for long distance radio hobbyists produced by Dr. Adrian M. Peterson, Coordinator of International Relations for Adventist World Radio. AWR carries the program over many of its stations (including shortwave). Adrian Peterson is a highly regarded DXer and radio historian, and often includes features on radio history in his program. We are reproducing those features below, with Dr. Peterson's permission and assistance.

Wavescan N446, September 10, 2017

VOA Mediumwave Stations in the Florida Keys - 2

On a previous occasion here in Wavescan [N391, August 21, 2016], we presented the story of the short term VOA mediumwave relay station that was established on Garden Island in the cluster of keys known as the Dry Tortugas, in the chain of small islands known as the Florida Keys. This station was subsequently reinstalled on Sugarloaf Key. The 50 kW transmitter for this station came from the mediumwave broadcast station WBAL in Baltimore, Maryland, and it operated in the Florida Keys under VOA on 1040 kHz from 1962 to 1966.

Over a period of time, there were two other radio transmitters in the Dry Tortugas Islands and these were installed on Garden Island and Loggerhead Key. The seven keys and associated islets and rocks in the Dry Tortugas are these days clustered together into a United States National Park at the western end of the Florida Keys.

Wireless station RF was installed in Fort Jefferson on Garden Island in 1902, and it was in use for just seven years. The reason for its closure was the difficulty in providing logistical support for personnel serving on the isolated Garden Key, and also the cost of providing all of this necessary support.

There was another radio station in the Dry Tortugas, and this was installed in the Radio Room at the base of the Dry Tortugas Lighthouse on Loggerhead Key, three miles west of Fort Jefferson. The Dry Tortugas Lighthouse on Loggerhead Key stood 150 ft. tall and its light could be seen 35 miles distant.

The first HYPERLINK "http://www.lighthousefriends.com/drytortugas_radiobeacon.jpg"radiobeacon in Florida, as a wireless guide for passing shipping, was established on Loggerhead Key on December 21, 1927. A small communication transmitter was installed in the Radio Room at the lighthouse and this was on the air on 3410 kHz under the callsign WST.

Another VOA mediumwave relay station was installed on Sister's Creek Island in Marathon Key and it was taken into regular service on November 12, 1962. This VOA station was made up of three transportable vans with a three tower antenna array, and the normal operating frequency of its 50 kW transmitter was 1180 kHz. However, during the Cuban Missile Crisis in the previous month of October, this station was temporarily on the air on 1040 kHz, the same channel as the other VOA station on Garden Island.

During the year 1982, the United States navy constructed another 50 kW medium radio station with four antenna towers at its communication center on Saddlebunch Key. Seven years later, during a massive rebuilding of the VOA station on Sister's Island-Marathon Key, the Saddlebunch station took over the regular VOA-Radio Marti programming that was beamed to Cuba.

During the Cuban crisis, which was precipitated by the collapse of the Soviet Union two years later in 1991, approval was granted for the usage of the full power output of 100 kW from VOA Marathon. The output from the twin 50 kW Continental transmitters was combined to provide the power level of 100 kW.

A new transmitter complement at 100 kW was installed in 2008, and during the following year new antenna towers were erected.

In our two part series on the mediumwave VOA relay stations in the Florida Keys, we have presented the story of four different stations. These have been:

Australian Shortwave Callsigns VLO

The good ship Moana was built in Dumbarton, Scotland for the Union Steamship Company of New Zealand and it was launched in 1897. At the time, the Moana was the largest Union ship afloat, and it carried passenger traffic and cargo in the Pacific service.

In 1903, the Moana was stranded on rocks near Victoria in British Columbia, and in 1911 it ran aground at Otago Harbour in New Zealand. After World War 1, this ship served mainly in the Trans Tasman service between New Zealand and Australia.

In 1921, the Moana was laid up in reserve at Port Chalmers in New Zealand, and then six years later she was hulked and towed to the Outer Mole at Otago Heads in South New Zealand where she was deliberately sunk as a breakwater barrier. This ship can still be seen to this day as a sunken wreck by local divers, and it can be seen on Google Earth as a dark shadow on the inner edge of the Outer Mole, parallel with the broken remnants of the old railway line.

On January 28, 1911, wireless apparatus was installed on the Moana and the given callsign was VLO. This identification callsign was retained by the Moana until she was laid up in 1921.

In the mid-1920s, this callsign VLO was recycled and applied to a small communication radio station on the small holiday island called Kawau in the eastern gulf, 25 miles north of Auckland in New Zealand. The radio station was installed in Mansion House by the experienced radiotrician Mr. T. Clarkson from Wellington.

That is the last known occasion for the usage of the callsign VLO. In 1927, New Zealand dropped the radio prefix V and accepted the radio prefix Z. It is true, VLO would have to be an Australian shortwave callsign, but there are no known records that list the callsign VLO anywhere, not in Australia, neither in New Guinea, nor in any of the other Pacific islands.

However, soon after the radio prefix in New Zealand was changed from V to Z in 1927, there was a usage of the callsign ZLO and it was applied to a small communication station located at Half Moon Bay on Stewart Island, south of the South Island of New Zealand. This ZLO was inaugurated in 1931, but it was closed during the following year after a new underwater cable connected Stewart Island with the island of South New Zealand.

Then, there was a new ZLO that was heard in the United States at a very good level in September 1935. This new station was described as a commercial station and it was noted on 12.1 MHz. The station was listed as Radio Wellington with 1 kW, and this would suggest that the callsign ZLO was not a new transmitter, but rather a channel callsign for either of the already established communication stations ZLT or ZLW.

There was one other radio station in New Zealand with the callsign ZLO and this was the navy communication station at Waiouru in the North Island; but that is a long story for another occasion.