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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, July 1, 2012

The Greatest Mystery in the History of Aviation: What happened to Amelia Earhart? The Radio Story-Pt. 1

It is now 75 years since the unsolved disappearance of America's "queen of the air", the world-famed aviatrix, Amelia Earhart, the "darling of the sky." Amelia was born in Atchison, Kansas on July 24, 1897 as the middle child of three siblings. She made her first airplane flight, as a passenger, at Long Beach, California in 1920 at age 22. Then twelve years later, she flew a record breaking solo across the Atlantic, making an unscheduled landing in an open field in Ireland.

On March 17, 1937, Amelia Earhart set out westward on a round the world flight, leaving Oakland on the first leg of this record attempt, and landing in Honolulu nearly 16 hours later. At take off in Honolulu on March 20, the plane groundlooped; it was badly damaged, and it was shipped back to California for extensive repairs.

Two months later, 40 year old Earhart set out again on her second attempt at a round the world flight; this time, flying in an eastward direction. Her co-traveler was ex-PanAm navigator, 44 year old Fred Noonan.

They left Oakland, California without publicity on May 21, 1937, arriving in Miami, Florida with two intermediate overnight stops on the way. It was here in Miami that they faced the usual blaze of publicity when it was publicly announced that they intended to fly completely around the globe, via South America, Africa, Asia and the Pacific.

The official flight began from Miami on June 1, 1937, and in their onward flight, they made one stopover in the Caribbean, four in South America, eight in Africa, nine in Asia, and one in Australia, at Darwin, before arriving in Lae, New Guinea almost a complete month later on June 29.

While en route at Bandoeng in Java, Indonesia, they had the long distance flight instruments repaired, and it was here that Amelia came down with dysentery. In Darwin, the radio direction finder was repaired, and they also off loaded some items from the plane that were no longer necessary on their long flight. After a two day stay at Lae in New Guinea, they flew out mid morning on July 2 on the flight from which they never returned.

The airplane that Amelia Earhart was flying was a Lockheed Electra, model 10E, with registration number NR16020. This model was intended for use in civilian flights, with two crew and ten passengers. It was the first all metal airplane manufactured by Lockheed at their factory in Burbank, California.

The Electra was originally developed in 1934 and it was noted for its unusual design with a twin tail. The plane was powered by twin motors manufactured by Pratt & Whitney, and the cockpit contained a two position flight deck. The plane was fitted with variable pitch propellers, and retractable landing gear.

The Earhart plane, model 10E, was specially modified for long haul usage. Most of the cabin windows were blanked out, leaving only those that would enable visual observations by the flight personnel.

A total of 12 additional fuel tanks were installed; 6 in the wings, and 6 in the passenger cabin in the empty space where the passenger seats would normally be installed. The total fuel capacity was 1150 gallons, thus enabling a range of more than 4,000 miles at a cruising speed of 190 mph, and a flight ceiling of nearly 20,000 feet.

The two wings on this shiny aluminum alloy plane were painted a strong red, with the identification number NR16020 screened in black under the left wing and onto the top of the right wing, and also upon the tail. Amelia took delivery of this new production, her modern new airplane, on her 39th birthday, July 24, 1936. It was financed largely by Purdue University in West Lafayette, Indiana.

The radio equipment in this Lockheed Electra 10E consisted of a standard 12 volt aircraft transmitter and receiver manufactured by Western Electric. The three channel transmitter, model number WE13C, was rated at 50 watts, and it was factory adjusted for use on 500 kHz, 3105 kHz and 6120 kHz. A factory modification enabled the transmission of Morse Code, by switching in a BFO, beat frequency oscillator.

The operational controls for the transmitter were mounted in the cockpit but the transmitter itself was installed next to the navigator's table. The official American callsign was KHAQQ.

The aircraft receiver, model WE20B, was a regular 4 band aircraft receiver, with reception on longwave, mediumwave, tropical shortwave and international shortwave. The tuning controls were located in the console between the two pilot positions, and the receiver itself was installed under the right seat.

The main antenna was a V doublet on top of the plane, with stubby masts above the fuselage and on top of the twin tails. Another main antenna was a long trailing wire underneath the plane that needed to be unrolled and deployed when in use. However, the available evidence would suggest that this antenna was missing, either by removal before leaving the United States, or by accident as the plane was taking off from the unpaved, rough airstrip at Lae in New Guinea.

There was also a newly designed Bendix direction finder on the plane, with a rotatable loop above the cockpit, and complicated electronic equipment attached to the radio receiver.

At exactly 10:00 am local time in New Guinea, or midnight GMT (as it was in those days) on Friday July 2, 1937, Amelia Earhart took off from the airstrip at Lae for the 18 hour flight to the scheduled landing at the temporary air strip on Howland Island, way out in the central Pacific. The fuel tanks of the heavily laden Lockheed Electra 10E contained sufficient aviation fuel for the 18 hour flight of more than 2-1/2 thousand miles, plus an extra 4 hours for emergency usage.

The flight of the Electra took them out over the western Pacific, and 4 hours and 18 minutes later, Lae aviation radio, PAE, received a radio communication from Amelia Earhart, KHAQQ, on 6210 kHz, her daytime channel, stating all is well. One hour later, a similar message was received. Nauru Radio, VKT, also heard several similar transmissions from the aircraft on the same channel, 6210 kHz.

At 07:18 GMT, with darkness coming on, Amelia switched to the night time channel, 3105 kHz, and many weak and hard to decipher messages were heard by the Coast Guard Cutter, "Itasca," NRUI, stationed at Howland Island. Some ships in the area, and other island based radio communication stations in the Pacific, also heard several of these garbled messages.

On only one occasion, was there a two way transmission between the "Itasca" at Howland Island and the airplane. At 1930 GMT soon after local sunrise, Amelia acknowledged that she had heard a transmission from the relief ship "Itasca."

The final confirmed radio message from the Electra, KHAQQ, was received by the "Itasca," NRUI, at 2044 GMT, when Amelia stated that they could not see the "Itasca", nor Howland Island. She stated that the fuel was low, and they were running on a line, 157-337 degrees, SE-NW.

So what happened to Amelia Earhart and Fred Noonan in the Lockheed Electra 10E? There is much speculation, and we will continue this story here in Wavescan, in two week's time.