Plane in the lagoon at Orona

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Tom Maxwell
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Re: Plane in the lagoon at Orona

Post by Tom Maxwell »

During the search and after the 4 July, west coast hams Pierson, McMenamy and other experienced radio operators as well as Coast Guard radio San Francisco NMC began to hear and log calls by Itasca and replies from a radio they identified as the Electra. The Itasca radio room had consulted the transmitter technical manuals and resolved the voice tuning issue. During the critical approach and search, the flight could not hear (voice) from the Itasca because the 3105 Kc voice transmissions at long range were very weak or nonexistent and did not get fixed until the 4 of July. 

In 1937 the Navy/Coast Guard did not use voice for at sea communications. The communication was always done with keyed code. Where key code could be encrypted, the voice modulation could not. So the Itasca was not throughly familiar with voice transmission. In addition to the short and long timing, the modulated CW (mcw) used two low frequency modulating tones for the dit and dah of the code. A long range test of the mcw had been completed when San Francisco reported receiving Vs (dit dit dit dah) from the Itasca. With the low tone modulation, typically 650 cycles for dah and 800 cycles for dit, the transmissions were said to have “music”. 

The key code modulation and voice modulation used two separate tuned circuits prior to high power amplification. The key code modulation requires carrier time on and off and the “music” tones. The Itasca radio technicians assumed tuning a transmitter for key, all  they had ever done in the past, was good for both key and voice. The technicians were likely unaware of the voice modulation tuned circuits, having never used or tuned them.
 Several messages from the San Francisco CG headquarters questioned the 3105 Kc voice operations until the last day of June and requested a priority effort to check out the voice capability. The Itasca log has no record of a priority effort to do so or message that the 3105 Kc was operating properly before the flight left Lae. However, the Howland amatuer radio log recorded, on July 1 that Itasca was testing 3105 Kc “fone”-voice with San Francisco CG radio NMC. The Howland log does not indicate if the tests were successful. The Coast Guard station San Francisco NMC reported hearing voice from Itasca and termed it a “first test” on July 4. Also Itasca couldn’t transmit voice on 6210 Kc. Why not? What did Itasca intend to do if Amelia arrived later in the day using the daytime frequency 6210 Kc? No voice on 7500 Kc and no voice on 3105 Kc.

Elgen Long, at the end of his very long study, concluded the Itasca transmitter 3105 Kc or transmission antenna was faulty during the approach and search for Howland by the world flight.

Tom Maxwell
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Re: Plane in the lagoon at Orona

Post by Tom Maxwell »

Following the RDF plan of trying high frequency first, Amelia called Itasca at “200 miles out” to request a bearing as she made noise with the microphone (whistling?) and to ask Itasca to report on the half hour. The time of the radio call is logged :14//:15 past the hour, the normal scheduled time for her transmission. The anecdotal accounts from the Itasca radio room indicates the transmission lasted only seconds. But the log indicates as much as two minutes :14 through :15 after the hour. Again at “approx 100 miles” out, Amelia requested the radio bearing and whistling into the microphone for two minutes :44 through :45 past the hour. Once again the anecdotal reports from the Itasca radio room indicated only a few seconds of transmission. Why does the radio log indicate two minutes? The experimental RDF receiver on Howland did not get a bearing or receive any 3105 Kc signal in either case.
Not receiving any feedback from the Itasca and in accordance with the RDF plan, Amelia switched to the RDF loop antenna and tuned for low frequency signals at 333Kc and 545 Kc. No signals were detected because Itasca never transmitted a low frequency homing signal. An hour later, Amelia calls to say “been unable to contact you by radio”. The call 07:42 is a little before the scheduled time. All radio operators understood that radio covered communications and navigation. Why this call did not prompt the Itasca crew to transmit the homing signal Amelia had detailed in telegrams is not known. It did however, make the radio room aware that something had to be done so the Itasca began to broadcast repeating A….AAA on the emergency 500 Kc at 08:06. They had no way of telling the flight to look for the 500 Kc signal. By that time Amelia had returned to sending long dashes at 3105 Kc by using the microphone key in the hope of Itasca finding her location using the high frequency DF unit on Howland. Knowing the bearing of the long dashes would allow Itasca to easily find the Electra if ditching were required. But again, the Howland experimental unit failed to get the Electra's bearing.
With no communications and no homing signal, the flight turned south for the Phoenix islands. Noonan knew the only place to get the Electra down safely was on the quiet surface in the lagoon of one of the Phoenix Islands.

Tom Maxwell
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Re: Plane in the lagoon at Orona

Post by Tom Maxwell »

Fred Goerner was a through and respected researcher of the Amelia Earhart mystery. Also, after years of study and detective work, Fred remained open to alternative explanations. At the end of his extended review of his Saipan/Japanese capture investigations, he left this passage:

“Until the mystery reefs that lie between Howland and the Phoenix Islands are thoroughly searched and the lagoons of several of the islands are plumbed, the possibility that the aircraft can be found remains.”

Had investigators followed up on Fred Goerner's thoughts some 60 years ago, the aircraft would have been found. Most likely in much better condition than found today.
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