"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 15, 2012
The Greatest Mystery in the History of Aviation - Pt. 2: What happened to Amelia Earhart? Radio Messages from the Crash Site?
In our program two weeks back, we presented the 1st part in the story of Amelia Earhart in her 2nd attempt at circumnavigating the world by plane at latitudes approximating the equator. The flight began officially from Miami, Florida with Amelia as the pilot and Fred Noonan as the navigator on Tuesday June 1, 1937.
After making a total of 24 overnight stops in the Americas, Africa, Asia and northern Australia, they arrived in Lae, New Guinea right just before the end of the month. Three days later, at 10:00 am local time on Friday July 2, they flew out of Lae in their heavily laden Lockheed Electra 10E filled with aviation fuel, and 18 hours later, they disappeared into history, never to be seen again.
The last verified radio transmission from Amelia Earhart, KHAQQ, aboard the Electra was at 8:45 am local time on the same day, Friday July 2, 1937, though by now they had flown eastward across the other side of the International Date Line, quite near to Howland Island. This message stated that they were flying on a line approximately NW-SE, though in which direction, it was not stated. The radio signal was quite strong and loud, indicating that they were indeed quite close in the air to the co-ordinating Coast Guard vessel, USS "Itasca."
When no one in the Howland area actually saw nor heard the plane, and it did not land as planned on the new airstrip on Howland Island, rescue procedures were quickly implemented, just one hour later. Over a period of nearly a month, large areas of the ocean to the north of Howland Island were searched, but no evidence of a downed airplane was ever found.
During the subsequent 75 years since the mysterious disappearance of Amelia Earhart, many different theories have been proposed as to what happened; some quite plausible, but even more quite wild.
In view of the best available information, we would suggest that Amelia Earhart and Fred Noonan in their shiny Lockheed Electra had actually flown a little south in their flightpath towards the expected Howland Island, due to the fact that they veered a little south soon after they took off from Lae in order to avoid a rough weather pattern. According to a radio message, Amelia descended to 1,000 feet when they thought that they were close to Howland Island, though in actual fact this descent was apparently 50 miles, less or more, too early.
We would suggest that they thought their route lay a little north of Howland, when in reality they were veering a little south. They did not see the smoke trail from the ship itasca, which billowed out some 10 miles, probably towards the northwest. In addition, the flight charts of that era showed Howland Island mis-placed on the map by about 5-1/2 miles, though it is not stated in what direction.
Consequently, when the flying pair travelled south along the NW-SE line that they announced over the radio, instead of flying closer to the desired Howland Island, they were actually flying away from it.
Hence, with even the emergency fuel running low, when they saw a small island then they landed on it. Current research suggests that this island was Gardner Island, now known as Nikumaroro Island, some 300 miles south east of Howland.
It is stated these days that there were more than 300 post crash radio messages noted on the air back then, and these were heard mostly on 3105 kHz, with some on 6210 kHz. These two radio channels are the only ones that Amelia was known to use on this round-the-world flight, and 6210 kHz is itself the 1st harmonic (or if you prefer these days, the 2nd harmonic) of the fundamental frequency 3105 kHz.
Many of the radio signals noted on these two channels during the next few days were direct transmissions from searching parties, boats and planes and islands, and some were legitimate calls to the downed plane on their recognized channels. However, it is understood that some of the radio transmissions heard during this era were hoax calls; some with good intent, and some with mal-intent.
These days, current thought is that a small number of these so-called post landing radio transmissions were actually genuine, though not recognized as such at the time. It would appear from a detailed analysis of the post loss transmissions, that the plane landed somewhat safely, that it was on its wheels, and that the right hand motor was running at times in order to generate electricity for the batteries that powered the radio equipment.
None of these transmissions were heard well at any location, and none were correctly understood at the time. Some were in a garbled voice mode, and some were in clumsy Morse Code.
The two well known mediumwave stations in Honolulu, Hawaii, KGU with 2-1/2 kW on 750 kHz and KGMB with 1 kW on 1320 kHz, both transmitted direct messages to Amelia Earhart asking for a specific response to indicate her location. These days, it is now thought that Amelia did give a response with a transmission from the downed plane, a series of indistinct keyed dashes to indicate location.
Government and private search parties utilizing a dozen ships, more than 100 planes, and more than 3,000 men, hunted all over the neighboring areas for nearly a month, with no positive indication of what had happened to the downed fliers. We would conjecture that they simply died subsequently from one cause or another on that island.
In North America, four different people claimed that they heard the voice of Amelia Earhart on their radio receivers in the days immediately after the flyers were declared lost. One was Betty Klenck in St. Petersburg Florida, a 15 year old school girl at the time, and she wrote down a brief diary of what she heard on the family's shortwave radio receiver. Then there was Dana Randolph, aged 16, in Rock Springs Wyoming; and Mabel D. in Amarillo Texas; and Thelma L. at St. Stephen in New Brunswick, Canada.
Each of these people heard the same sort of information on shortwave on their family radio receiver and they believed that they heard direct transmissions from Amelia Earhart in the downed airplane. It has been suggested that each of these four listeners heard the transmissions from the plane on a harmonic of the fundamental frequency 3105 kHz.
On Thursday July 8 and Thursday July 15, just days after the loss of the Lockheed Electra, a commercial radio program under the title, "March of Time" was syndicated across the United States on mediumwave, and probably also on shortwave. Each of these two programs contained voice excerpts from both Amelia Earhart and Fred Noonan.
What was it that these four people in North America heard on their family shortwave receivers?We would suggest that each of these four people could have heard genuine news reports on radio about the lost fliers and/or the "March of Time" broadcasts on shortwave. The reception on the family radio receivers could have been a relay from one of the known shortwave stations that were on the air during that era, or a harmonic from a local mediumwave station, or an image frequency due to the shortcomings of receiver circuitry.
Regardless of what they heard, we would emphatically state that there was no way that a harmonic signal from a low powered 50 watt transmitter in an airplane on the ground in the central Pacific could propagate adequately into continental North America and be heard on family owned shortwave receivers with simple aerial systems. The aircraft radio, even when the plane was in the air, could not be heard well on dozens of professional radio receivers with directional antenna systems throughout the Pacific basin.
Currently, plans are underway for another expedition to Gardner Island in the hopes of finding some left over part of the missing plane; and currently, many people in many places are honoring the pioneer spirit of the famous aviatrix, Amelia Earhart, and her experienced navigator, Fred Noonan.
We might add, that another girl named Amelia Earhart is currently training in the United States with the intent that she will attempt some time soon to circumnavigate the Earth by plane. She claims to be distantly related to the original Amelia Earhart, she was named in honor of the 1937 aviatrix, and she plans to follow as much as possible the same route taken by her famous namesake in the 1937 event.