Gray’s “Amelia Didn’t Know Radio” Conclusion
Today we present the conclusion of Almon Gray’s “Amelia Didn’t Know Radio,” which appeared in the December 1993 edition of the Amelia Earhart Society Newsletters. (Boldface emphasis mine throughout.)
THE HOWLAND ISLAND RADIO DIRECTION FINDER: Earhart obviously had misconceptions concerning the radio direction finder on Howland. She apparently thought it was a functional equivalent of the Pan American Adcock systems that had furnished her bearings from her 3105 kcs signals during the Alameda-Honolulu flight, and she expected that the DF station would be monitoring her signals and it would take a bearing when she asked the Itasca for one. The bearing would be passed to the ship, which would send it to her on the next schedule. This explains why she repeatedly asked the Itasca for bearings on 3105 kcs. She did not expect the ship to take the bearings with its own DF gear — she was counting on the Howland Island DF.
I think there was some basis for her misconception. After changing to an east-about route, and while the Lae-Howland leg was being studied, Earhart and Noonan suggested to the Coast Guard that a radio direction finder be set up on Howland. According to an unpublished manuscript by the late Capt. Laurance F. Safford, U.S. Navy, (Retired) [which later became Earhart’s Flight Into Yesterday: The Facts Without the Fiction, 2003], it was Richard Black, scheduled to go to Howland in the Itasca, who arranged for the Howland DF.
Unfortunately, Earhart did not understand the relationship between wavelength and frequency nor how to convert one to the other.
Apparently reacting to Noonan’s suggestion, he recommended to George P. Putnam, Earhart’s husband and business manager, that they borrow a high-frequency radio direction finder from the Navy. Subsequently Black, assisted by Lt. Daniel A. Cooper of the Army Air Corps, also going to Howland in the Itasca, obtained the desired apparatus from a Navy patrol plane at Pearl Harbor and took it to Howland, where it was jury-rigged to provide a temporary DF capability. An Itasca radioman operated it.*
*[Incorrect: Navy Radioman 2nd Class Frank Cipriani was temporarily assigned to operate the Howland Island direction finder for the Earhart flight.]
According to Captain Safford, the apparatus was “ . . . a 24-volt aircraft type of loop-direction-finder similar to the one installed in Miss Earhart’s plane — possibly its twin.” Black later described it to author Fred Goerner as an “experimental model of some of the direction finders we used in the war.” It may have been one of the three experimental receivers built by Bendix, and thus a twin to Earhart’s. Cooper, who helped Black obtain the DF gear, wrote in his official report: “It is true that an airplane direction finder capable of working 3105 KC had been borrowed from the Navy just prior to sailing. This was set up on Howland mainly as a standby in case the ship’s direction finder on 500 KC should go out.”
This clearly shows that Cooper, Black, and Putnam believed that inasmuch as the frequency range of the receiver included 3105 kcs, it would be able to take bearings on that frequency. Putnam communicated frequently with Earhart and certainly would have kept her apprised of developments regarding the Howland DF: when he told her (while she was in Darwin) that the Itasca reported the DF had been installed on Howland, she had good reason to believe that en route to Howland she would be provided with bearings taken on her 3105 kcs signals just as they had been provided her by PAA on the Alameda-Honolulu flight.
She was wrong. The apparatus undoubtedly was an excellent receiver and was capable of receiving a wide array of frequencies well above Earhart’s 3105 kcs. For direction finding, however, it used a simple rotatable loop-type antenna, which because of the very nature of radio wave propagation, is incapable of obtaining meaningful bearings over significant distances on frequencies higher than about 1800 kcs. On higher frequencies, signals can be heard but no steady null or “minimum” (which indicates the bearing) can be obtained. It should have been no surprise then that the Howland DF was unable to get bearings on the plane. The operator complained that Earhart had not transmitted signals long enough for him to take a bearing, but this was irrelevant; longer transmissions would not have helped.
- Nauru. On July 3 (GMT date) an operator at Nauru radio station VKT sent the following “wire note” to RCA radio station KPH at San Francisco, with the request that it be passed to the Itasca:
VOICE HEARD FAIRLY STRONG SIGS STRENGTH TO S3 0843 0854 GMT 48.31 METERS [6210 kcs] SPEECH NOT INTERPRETED OWING BAD MODULATION OR SPEAKER SHOUTING INTO MICROPHONE BUT VOICE SIMILAR TO THAT EMITTED FROM PLANE IN FLIGHT LAST NIGHT WITH EXCEPTION NO HUM ON PLANE IN BACKGROUND.
The Nauru operator was a professional wireless operator, well qualified to judge the quality of radio signals. He had heard some of Earhart’s transmissions the night before and was familiar with the sound of her voice and of the cockpit background noise. That he was able to recognize the voice but was unable to understand what was being said, and his diagnosis of probable over modulation, jibe with the reports of the wireless operator at Lae and the DF operator at Howland. He had nothing to gain by fabricating information. Given this — and because Earhart probably was the only woman in that part of the world transmitting voice signals on 6210 kcs, there is a strong case for ascribing the signals to Earhart’s plane. Since more than 12 hours had elapsed between the time the Itasca last heard the plane and the time the Nauru operator intercepted the signals, the aircraft certainly was no longer in flight. The absence of the “hum” (engine noise) in the intercept tends to confirm this.
- Pan American Airways. Shortly after Earhart became overdue at Howland, the Coast Guard requested PAA assistance in the search. The stations at Mokapu Point, Midway, and Wake almost immediately began to monitor the plane’s frequencies consistent with available personnel, and were prepared to take bearings on any signals reasonably believed to be coming from the plane. The airline established a special radio circuit linking the three stations. Numerous weak signals were heard but nothing of interest was picked up until July 5 (GMT). The following is extracted from a report made by the Radio Operator-in-Charge at the Wake Island station, R.M. Hansen:
“At 0948 a phone signal of good intensity and well modulated by a voice but wavering badly suddenly came on 3105. While the carrier frequency of this signal did not appear to vary appreciably, its strength did vary in an unusually erratic manner and at 0950, the carrier strength fell off to QSA2 [2 on a scale of 0 to 5] with the wavering more noticeable than ever. At 0952, it went off completely . . . . At 1212 [GMT 5 July] I opened the DF guard on 3105 KC. At 1223 a very unsteady voice-modulated carrier was observed on 3105 KC appx [sic]. This transmission lasted until 1236. I was able to get an approximate bearing of 144 degrees. In spite of the extreme eccentricity of this signal during the entire length of the transmission, the splits were definite and pretty fair. . . . After I obtained the observed bearing, I advised Midway to listen for the signal (couldn’t raise Honolulu). He apparently did not hear it. This signal started in as a carrier strength of QSA5 and at 1236, when the transmission stopped it had gradually petered out to QSA2 during the intervals when it was audible.
“The characteristics of this signal were identical with the signal heard the previous night (0948 GMT) except that at DF the complete periods of no signal occurred during shorter intervals. . . . While no identification call letters were distinguished in either case, I was positive at that time that this was KHAQQ [Earhart’s aircraft call letters]. At this date I am still of this opinion.”
- Midway. At 0638 5 July (GMT), the station heard a signal having the same characteristics, and almost certainly the same station. The operator computed a quick bearing of 201° True, but the signal was not audible long enough to take a really good bearing and the 201° figure was labeled “approximate.”
- Honolulu (Mokapu Point). This station also heard the 3106 [sic] kcs “peculiar signal” several times. From 1523 to 1530 on 4 July (GMT), the station attempted to get a bearing; the signal was weak and shifting, and only a rough bearing was obtained. It was logged as 213° but was by implication a doubtful bearing. Sometime between 0630 and 1225 GMT another bearing was attempted. The log describes it thus: “Signals so weak that it was impossible to obtain even a fair check. Average seems to be around 215 degrees — very doubtful bearing.” It is obvious that the bearings from Honolulu were much inferior to those taken from Wake and Midway; they are useful mainly that the unknown station continued to function.
Few paid any attention to these intercepts at the time because no one was aware that Earhart’s radio signals had been abnormal. Had it been known that she was having over-modulation problems more attention probably would have been given them because the wavering in the carrier strength is consistent with a varying degree of over modulation rapidly increasing and decreasing carrier power. The gradual drop in signal strength from QSA5 to QSA2 over a span of 13 minutes is consistent with the further discharge of an already partially discharged storage battery power supply. The peculiar signals on 3105 kcs heard by Wake, Midway and Honolulu may very well have come from the Earhart plane, and it is likely that the radio bearings taken on these signals by Wake was accurate within a degree or so. The one from Midway may have had a slightly larger error.
FREDERICK J. NOONAN: From personal observation, the writer knows that as of late 1935 Noonan could send and receive plain language at slow speeds, around eight to 10 words per minute. Recent research by Noonan biographer Michael A. Lang has revealed that circa 1931 Noonan held a Second Class Commercial Radio operator license issued by the Radio Division of the U.S. Department of Commerce. The license, which was valid for two years, certified that the holder was capable of: “Transmitting and sound reading at a speed of not less than 16 words a minute Continental Morse in code groups and 20 words a minute in plain language.”
CONCLUSIONS: Earhart failed to reach Howland, because she was unable to use the electronic aids that had been set up to help her find the Island. Her inability to hear the Itasca on the communication channel precluded any possibility of receiving aid from the Howland DF. Therefore she was completely dependent upon bearings she could take on the Itasca beacon with her own DF.
When it became evident that she would get no help from the Howland DF, Earhart prepared to take bearings on the Itasca’s beacon. She tuned in the beacon on her DF and heard the signals clearly. When she tried to take a bearing, however, she was unsuccessful because she could not get a “minimum.” She had no idea why she could not get a bearing, nor did she know what to do to improve the situation. Lack of two-way communication with the ltasca prevented her from getting advice from the ship. Apparently, after a final unsuccessful attempt to have a bearing taken on her 3105 kcs frequency, she gave up on radio navigation and left the area.
The direct cause of the flight’s failure was Earhart’s unwitting error in designating 7.50 Mcs as the beacon frequency for the Itasca.
The probable cause for the antenna system failure was malfunctioning of the “send-receive” relay, located physically in the transmitter unit, which left the receiver without an antenna. The relay probably malfunctioned because of damage by lightning or heavy static discharge. (End of Almon Gray’s “Amelia Didn’t Know Radio.”)
As a layman whose technical knowledge and ability barely extends to mowing the lawn, something that’s becoming increasingly difficult as I progress into my 70s, Almon Gray’s radio sophistication boggles my mind. But Gray’s entire, comprehensive radio analysis is based on one key assumption, which is that Amelia and Fred were actually trying to reach Howland Island. Without that one overriding element, Gray’s scenarios become strictly academic.
Over decades of study and discovery since the disappearance of Amelia Earhart, many researchers have concluded that Howland Island was not the real destination of her final flight, but was just another official piece of a larger puzzle, whose intricacies have yet to be definitively unraveled to reveal the true picture.
Indiana lawyer’s instructive ’92 letter to Goerner: U.S. cryptanalysis “reaching its zenith in 1937/1938”
In Chapter XIV of Amelia Earhart: The Truth at Last, “The Care and Nurture of a Sacred Cow,” I discuss several compelling aspects of the U.S. government’s longstanding refusal to disclose the truth that’s been hiding in plain sight in the Earhart matter for over 82 years, including a 1992 letter from Highland, Ind., attorney Michael Muenich to Fred Goerner. The Muenich letter brings the complex world of cryptanalysis into better focus, and strongly supports Goerner’s claim that we knew the Japanese had Earhart in their clutches, despite their assurances of assistance in the July 1937 search, which were later proven to be blatant lies. Boldface and italic emphasis mine throughout.
In his letter, Muenich, a civilian with a solid understanding of Navy radio intelligence capabilities, begins with a brief history of Navy cryptanalysis and code-breaking. He cites Admiral Edwin T. Layton’s 1985 book, And I Was There, not only for study of the days and months leading to Pearl Harbor, but “the first several chapters detail radio surveillance, intelligence, and capabilities during the 1930s.”
Muenich tells Goerner that our “level of sophistication” in reading the Japanese naval and diplomatic codes “was apparently reaching its zenith in 1937/1938,” and describes the overall intelligence situation in the Earhart disappearance as well as any single missive I can recall. Here’s the letter, with minimal editing:
March 30, 1992
Mr. Fred Goerner
Frederick Allan Goerner
Twenty-four Presidio Terrace
San Francisco, California 94118
RE: Amelia Earhart
Dear Mr. Goerner:
I presume by now you have seen the April issue of Life magazine, which has an article under the byline of Richard Gillespie and accompanying photos regarding the disappearance of Ms. Earhart. I, however, remain a skeptic. I have now had an opportunity to secure and review copies of your original volume and Klass’s [sic] volume and have reviewed them with an eye towards your theory of a landing in the Marshalls and ultimate transportation to Saipan. I also picked up a newer volume “Amelia Earhart: The Final Story” by [Vincent V.] Loomis and [Jeffrey] Ethel, published in 1985. If you have not yet had an opportunity to read this volume, I commend it to you as an excellent examination of the mystery.
Like you in Saipan, they have interviewed numerous witnesses in the Marshalls which place Earhart and Noonan on Mili atoll, specifically ditching off Barre Island. They have also located a number of Japanese witnesses which corroborate the recovery of Earhart and Noonan, together with their aircraft, by the naval research vessel Koshu thence to Jaluit, Truk and ultimately Saipan. Their theory closely parallels yours, with the exception of the routing from Lae, in that they do not subscribe to the “spy theory” of over flights in the vicinity of Truk or Saipan, but rather have them diverting South across Nukumanu and Nauru Islands. Unfortunately you, Messrs. Loomis and Ethel have witnesses, but no “hard” evidence, and Gillespie has “hard” evidence [sic], which isn’t conclusive as to Earhart, and no witnesses.
What caught my attention in the article, your book, and the book of Loomis/Ethel is the reference to radio transmissions, either from the vicinity of the Marshall or the Phoenix group. Gillespie referred to a Navy flying boat, HMS Achilles, and various stations over the Pacific, apparently Pan Am at Hawaii, Midway and Wake Islands, and advised the Navy that triangulation placed the aircraft in the Phoenix group. I believe your book makes reference to Navy stations on the west coast which picked up similar signals, possibly emanating from the Marshalls. I believe it may be radio signals that created the Navy’s secrecy and paranoia concerning this entire affair.
Also published in 1985 was “And I Was There” by Rear Admiral Edwin T. Layton. While the volume is directed to and addresses the issues of naval intelligence and the attack on Pearl Harbor, the first several chapters detail radio surveillance, intelligence and capabilities during the 1930s. I have enclosed copies of certain pages that detail this information; however the synopsis is as follows: Beginning with World War I, Herbert O. Yardley organized the first code breaking offices for the U.S. military. The cipher bureau was called MI-8 and worked with the British and French through the end of World War I. This office continued in existence until 1929 when it was prohibited by the U.S. Secretary of State, Stimson, against “reading other people’s mail.” However, prior to ceasing the operations, the Americans were able to establish the 5:5:3 – Ship tonnage ratio between Britain, the U.S., and Japan. The U.S. was reading Tokyo’s telegraphic instructions to its delegations, which allowed the Americans to read Japan’s hand in the poker game.
Apparently the Navy became very proficient in their trade and completely replicated what was then known as the Japanese Red code. While the operations were supposed to be terminated after the naval conference, they apparently became, at best, dormant throughout the late 20s and early 30s. You will repeatedly find the names of Joe Rochefort, Joe Wenger, Agnes Driscoll, Lawrence Safford, Tommy Dyer, Wesley A. “Ham” Wright, and other apparent geniuses in radio intercepts, intelligence, and cryptoanalysis throughout Layton’s book. The Navy operated a full network with listening stations in Guam, Shanghai, Peking, Cavite, Australia, Hawaii, and the west coast with all of the material ultimately delivered to Washington, cryptoanalysis stations Negat (Washington) Hypo (Hawaii) and Cast (Cavite).
In late 1930 the Japanese changed their naval code system and went from the Red book to the Blue book. Breaking the Red book had taken approximately three years, however given the level of experience and talent then available, the key to the Blue code was broken in September, 1931. Thereafter the Navy continued penetrating the new cipher system and for a period of eight years continued to read the Japanese “mail.” The level of sophistication with the blue code was apparently reaching its zenith in 1937/1938. In November, 1938 the eight-year-old Blue book was suspended and the Japanese adopted the “AD” code, then in June, 1939 the “AN” code, later to be designated as JN-25 which we penetrated and read throughout World War II.
In addition to reading the naval code we were also apparently reading merchant code and most significantly the Japanese diplomatic codes. Examples are the Japanese low-grade ciphers designated “PA-K2,” “LA,” “J-19” and the high-grade diplomatic code “Purple,” frequently referred to as “Magic.” Purple became effective in February, 1939. Its predecessor was Red, not to be confused with the Navy’s red code book. Both the Red and Purple diplomatic codes were machine code, with Red first coming into use in 1935. Colonel William F. Friedman developed the “M3” machine which was being used by the Japanese foreign ministry in 1935 to encode its most confidential communications. By 1936 we were regularly reading Tokyo’s diplomatic messages on this device. Ultimately a “Purple” machine was developed to read the diplomatic codes after 1939.
The point of this history is this: If the U.S. Navy was prepared to spend $4,000,000 and the allocation of numerous naval vessels to the search for Amelia Earhart, I found it inconceivable, given the ability of the U.S. Navy to read both the diplomatic and naval codes, and the extent of their direction finding and cryptoanalysis [sic] stations around the Pacific, that they did not listen in on Japanese communications and follow the “search” from the Japanese side. . . . Most interestingly, most of the Japanese “fleet” that was supposed to be scouring the Pacific was in fact tied up in Japan preparatory to its operations in China which began on July 5th.
Navy signal traffic would have clearly indicated that this “fleet” was not where the Japanese claimed it to be, and may even have been able to determine the activities of the Koshu in the Marshalls. It must have driven the Navy crazy to read Japanese communications about the great search, if it did, in fact, know that no such search was being made. It is also quite possible that Navy direction finders pinpointed Earhart’s aircraft or even the Japanese recovery, since they certainly had that capability, however were unable to get our naval vessels near that area because the Japanese, knowing Earhart to be down in the Marshalls, had grabbed her first and refused to allow our Navy into the area.
Finally none of this material could be released to the public without compromising our signals intelligence and warning the Japanese that we were reading their mail. That, in my opinion, would be more than sufficient basis for the Navy’s paranoia about secrecy in this entire matter, since little, if any, of the signals intelligence was released until the 1970’s or later.
Your search and other searches at “naval intelligence” probably would not have revealed the information and files at “naval communication” which apparently were two separate and distinct operations which frequently did not share information. Unfortunately that led to the debacle at Pearl Harbor and may have also been involved in the Earhart mystery. According to the bibliography attached to Layton’s book, record group 457 of the National Security Agency on file in the national archives contains portions of the radio traffic between 1940 and 1945 and encompass over 300,000 messages intercepted and decrypted. I presume there are similar record groups that cover the summer of 1937. . . . [A]n examination of naval communication records, records of OP-20-G and the National Security Agency of signal intercepts during June, July, and August of 1937 might well locate the key to resolving the mystery.
Very Truly Yours,
Michael L. Muenich
The records of OP-20-G and the National Security Agency of signal intercepts during June, July and August of 1937 referenced by Muenich are precisely the point: If these records contain Navy intercepts of Japanese messages indicating they had Earhart and Noonan in custody or even knew of their whereabouts, as some believe, it would be the smoking gun many have long sought. Although I haven’t personally searched the National Archives for these records, others more inclined to navigate and endure the stifling NARA bureaucracy have done so and confirmed what many have strongly suspected—a gap exists where the records of intercepted Japanese radio transmissions would normally be found, from 1935 to 1940.
Are these intercepts still being kept at Crane, Ind., as Carroll Harris suggested to Goerner in 1980, or do they even exist at all anymore? Were the top-secret files destroyed “in the interest of national security” somewhere along the line, perhaps? Barring some unimaginable development — a miracle, in my opinion — we’ll never know the answers to these vexing questions, as it appears the key to the vault that holds Earhart secrets was thrown away long ago.
For further discussion of U.S. and Japanese radio transmitting and intercept capabilities, please see pages 263-264 and “Chapter III: The Search and the Radio Signals” in Amelia Earhart: The Truth at Last.
Conclusion of Gray’s “Amelia Earhart and Radio”: Former PAA flight officer’s findings still fascinate
In the conclusion of Almon Gray’s “Amelia Earhart and Radio,” the former Pan American Airways radio flight officer examines further technical and other aspects of Amelia Earhart’s final flight, including the origin and effectiveness of the radio direction finder on Howland Island, some of the possible post-flight radio transmissions that may have originated from the Earhart Electra, and Fred Noonan’s alleged drinking problem as it may have affected the flight. As always, the real mystery is what transpired aboard the Electra in the hours before and after her last radio transmission, and the biggest question remains unanswered: Was Amelia actually attempting to reach Howland Island? If she was, then Gray’s conclusions remain highly relevant today.
“Amelia Earhart and Radio,” Conclusion
By Almon Gray
THE HOWLAND ISLAND RADIO DIRECTION FINDER
Obviously Earhart had a misconception of the radio direction finder installed on Howland Island. She apparently envisaged it as being a PAA type Adcock high frequency system, or its functional equivalent, which would take bearings on her 3105 kHz signals and send them to her just as the PAA station at Mokapu Point had done during her flight from Oakland to Honolulu. Because of that she repeatedly asked Itasca to take bearings on 3105 kHz and transmitted signals upon which bearings were expected to be taken. It appears that there may have been some justification for her having that concept.
When the decision was made to fly easterly around the world, and the long Lae-Howland leg was being studied, Earhart and Noonan suggested to the Coast Guard that a radio direction finder be set up on Howland (“PLANE SUGGESTS DIRECTION FINDER BE SET UP ON ISLAND, IF PRACTICABLE”). According to the research of Capt. Laurance F. Safford, USN, it was at about this time that Mr. Richard B. Black, the Department of the Interior representative, who was to go to Howland in Itasca, conceived the idea of “borrowing” a so-called high frequency radio direction finder from the Navy to use on Howland Island. Black advised G.P. Putnam, Earhart’s husband and business manager, of his plans and advised him when the gear had been obtained and put aboard Itasca. No doubt Putnam passed this information along to Earhart.
In a message sent June 27 to Commander, San Francisco Division, USCG, the C.O. Itasca [Cdr. Warner K. Thompson] reported on his readiness for supporting the upcoming flight. One item was “DIRECTION FINDER INSTALLED ON HOWLAND.” This fact was reported to Mr. Putnam, then in San Francisco, and he in turn passed the news to Earhart, who was then at Darwin, Australia. While the Itasca message did not specifically say “High Frequency Direction Finder,” there apparently had been sufficient other information, probably via telephone from Putnam, to cause Earhart to believe that it was such a device. She likely assumed that the DF had been installed at Howland in response to the suggestion made earlier by Noonan and herself , and fully expected it to be a functional equivalent of a PAA-Adcock system.
According to Capt. Safford, who was in an excellent position to know, the direction finder station on Howland Island actually consisted of an aircraft type radio receiver and an aircraft type rotatable loop antenna which had been “hay-wired” together into a temporary DF installation. It operated off storage batteries borrowed from Itasca. The receiver and loop had been “moon-light requisitioned” (obtained by informal means) by Mr. Black and Lt. Daniel Cooper of the Army Air Corps, from a Navy patrol plane at Fleet Air Base, Pearl Harbor.
The equipment appears to have been a military version, or perhaps a twin, of the Bendix receiver and loop in the Earhart plane. At any rate, with a loop antenna, it certainly was not a high frequency direction finder and the probability of taking meaningful bearings with it on 3105 kHz over any significant distance, was practically nil. The Howland DF operator [Radioman 2nd Class Frank Cipriani] had only two opportunities to try taking a bearing on the plane, and in each case the plane’s transmission was so short that a really good attempt could not be made. Had the transmissions been sufficiently long the operator no doubt would have found that he could get no “minimum” and hence no bearing.
On July 3 (GMT date) an operator at public service radio station VKT, Nauru, sent the following “wire note” (an informal communication between operators) to RCA radio station KPH at San Francisco, with the request that it be passed to Itasca:
VOICE HEARD FAIRLY STRONG SIGS STRENGTH TO S3 [at] 0843 and 0854 GMT 48.31 METERS (i.e. 6216 kHz) SPEECH NOT INTERPRETED OWNING BAD MODULATION OR SPEAKER SHOUTING INTO MICROPHONE BUT VOICE SIMILAR TO THAT EMITTED FROM PLANE IN FLIGHT LAST NIGHT WITH EXCEPTION NO HUM ON PLANE IN BACKGROUND.”
Note that these signals were heard about 12-and-a-half hours after Itasca last heard the plane.
There is nothing that directly and positively connects these signals with the Earhart plane, however there is indirect evidence that warrants serious consideration:
(a) The frequency (6210 kHz) was right for it being the plane. It was not a commonly used frequency in that area.
(b) The Nauru operator reported good signal strength and was able to judge the tone or timbre of the speaker’s voice yet was unable to understand what the speaker was saying. He suggested the possibility of modulation problems. The operator who had checked the plane at Lae and the DF operator at Howland who was trying to take a radio bearing on the plane, both had noted similar symptoms and suggested possible modulation problems.
(c) The probability of there being more than one transmitter in the area exhibiting the same symptoms of over-modulation on the same frequencies at essentially the same time is very small.
It is this writer’s opinion that the signals intercepted by Nauru were in fact from the Earhart plane no longer in flight.
PAN AMERICAN AIRWAYS
Shortly after the Earhart plane became overdue at Howland, the Coast Guard requested PAA to use its communication and radio direction finding facilities in the Pacific areas to assist in the search for the plane and survivors. Instructions were immediately issued for the stations at Mokapu Point, Midway and Wake to monitor the plane’s frequencies as much as limited personnel would permit and be prepared to take radio bearings on any signals heard which might reasonably be believed to be coming from the plane. A special radio circuit was set up to permit intercommunication among the three stations. Numerous weak signals were heard but nothing of interest until 0948 July 5, GMT time and date. The following is extracted from a report made by R.M. Hansen, the Radio Operator in Charge at the Wake Island station:
“At 0948 a phone signal of good intensity and well modulated by a voice but wavering badly suddenly came on 3105 kc. While the carrier frequency of this signal did not appear to vary appreciably, its strength did vary in an unusually erratic manner and at 0950, the carrier strength fell off to QSA 2 (2 on a scale of 0 to 5) with the wavering more noticeable than ever. At 0952, it went off completely. At 1212 (GMT July 5) I opened the DF guard on 3105 kc. At 1223 a very unsteady voice modulated carrier was observed on 3105 kc approximately. This transmission lasted until 1236 GMT. I was able to get an approximate bearing of 144 degrees. In spite of the extreme eccentricity of this signal during the entire length of the transmission, the splits were definite and pretty fair.
“After I obtained the observed bearing, I advised Midway to listen for the signal (couldn’t raise Honolulu). He apparently did not hear it. This signal started in at a carrier strength of QSA5 (5 on a scale of 0 to 5) and at 1236, when the transmission stopped, it had gradually petered out to QSA2 during the intervals when it was audible. The characteristics of this signal were identical with those of the signal heard the previous night (0948 GMT) except that at DF the complete periods of no signal occurred during shorter intervals. While no identification call letters were distinguished in either case, I was positive at that time that this was KHAQQ [Earhart’s plane]. At this date I am still of this opinion.”
Midway heard a signal having the same characteristics, and almost certainly the same station, at 0638 GMT July 5. A quick bearing of 201 degrees True was obtained, however the signal was not audible long enough to take a really good bearing and the 201 degree figure was labeled “approximate.”
Honolulu (Mokapu Point) also heard the “peculiar signal” on 3105 kHz several times. From 1523 to 1530 GMT July 4 an attempt was made to take a bearing on it, however due to weakness and shifting of the signal, only a rough bearing could be obtained. It was logged as 213 degrees, but it was implied that it was a doubtful bearing. Sometime between 0630 and 1225 GMT another bearing was attempted on the “peculiar signal.” The log describes it thus: “SIGNALS SO WEAK THAT IT WAS IMPOSSIBLE TO OBTAIN EVEN A FAIR CHECK. AVERAGE SEEMS TO BE AROUND 215 DEGREES — VERY DOUBTFUL BEARING.” It is obvious that the bearings from Honolulu were greatly inferior to those taken from Wake and Midway and are useful mainly as indications that the unknown station continued to function.
Not much attention was paid to these interceptions at the time because no one was aware that Earhart’s radio signals had been abnormal. Had it been known that she was having over- modulation problems more attention probably would have been given them because the “Wavering” in the carrier strength is consistent with a varying degree of over-modulation rapidly increasing and decreasing carrier power. The gradual drop of signal strength from QSA5 to QSA2 over a span of 13 minutes is consistent with the further discharge of an already partially discharged storage battery power supply. The peculiar signals on 3105 kHz heard by Wake, Midway and Honolulu may very well have come from the Earhart plane, and there is good reason to believe that the radio bearing taken on those signals by Wake was accurate within a degree or so. The one from Midway may have had a somewhat larger error.
(Editor’s note: A number of radio operators, including several in the continental United States, reported hearing signals that they believed originated from Earhart and Noonan, and some have already been presented on this blog. Please see “Earhart’s ‘post-loss’ messages’ Real or fantasy?” and “Experts weigh in on Earhart’s ‘post-loss’ messages.”)
FREDERICK J. NOONAN
There has been much speculation as to whether or not Fred Noonan could send and receive International Morse code. From personal observation the writer knows that as of late 1935 Noonan could send and receive plain language at slow speeds, around eight to 10 words per minute. Recent research by Noonan biographer Michael A. Lang has revealed that circa 1931 Noonan held a Second Class Commercial Radio Operator license issued by the Radio Division of the U.S. Department of Commerce. Second Class licenses of that vintage certify that the holder has been examined and passed the following elements:
(a) Knowledge of the general principles of electricity and of the theory of radio telegraphy and radiotelephony.
(b) Adjustment, operation and care of apparatus.
(c) Transmitting and sound reading at a speed of not less than sixteen words a minute Continental Morse in code groups and twenty words a minute in plain language.
(d) Use and care of storage battery or other auxiliary.
(e) Knowledge of international regulations and Acts of Congress to regulate radio communications.
Those writing about the Earhart disappearance have, in general, been very rough on Noonan because of his admitted problem with alcohol. In some cases much rougher than was justified by the facts. For example in one book it is related that the night before the departure from Lae for Howland, Noonan went on a binge and did not get to the airfield until just before the plane was due to take off, and even then was so intoxicated that he had to be helped aboard the plane. The implication being that he was largely responsible for the failure of the flight. The official report of Guinea Airways Ltd., at Lae, made in response to a request from the U.S. Government, paints quite a different picture. According to it the Lae wireless operator made attempts all throughout the day of June 30 to get time signals, requested by Earhart and Noonan, to permit Noonan to check his chronometer, but owing to local interference was unsuccessful that day. That indicates that Noonan spent most of June 30 at the radio station.
At about this point, Earhart decided to take off for Howland Island at 9:30 a.m. on July 1, subject to obtaining the time signal.
At 6:35 a.m. July 1st Earhart took the plane up on a 30-minute test hop after which the tanks were topped off and she was ready to go, except that a time signal had not yet been obtained. This day the difficulty was at the radio station which transmitted the signals. Extraordinary steps were taken to get a time signal but when one had not been obtained by 10:50 a.m. Earhart decided to postpone her departure until the next day, July 2. During the rest of the day constant watch was kept for the reception of time signals and finally at around 10:20 p.m. an excellent signal was received by Noonan which showed his chronometer to be three seconds slow. Noonan obviously had spent most of that day at the radio station.
On July 2 at 8:00 a.m. another time signal was received, this one from Saigon, and the chronometer checked the same as the previous night. Both Noonan and Earhart expressed their complete satisfaction and decided to leave at 10:00 a.m., which they did.
Only Noonan would have checked the chronometer, so the report seems to indicate clearly that Noonan was sober and in good shape at 8:00 a.m. and probably was that way when the plane took off.
From the standpoint of radio, Earhart’s decision to rely completely on radiotelephony, and her removal of the trailing antenna, showed poor judgment and introduced unnecessary and unjustifiable risks. However it cannot be denied that she got as far as Lae without trouble with what she had. It was her mistake in designating 7500 kHz as the homing frequency for Itasca that got her into deep trouble. Even that difficulty probably could have been overcome had she been able to communicate with Itasca and agree on a suitable homing frequency. Fate intervened, however, and something occurred in her receiving system which made it impossible for Earhart to hear any signals with her gear set up in the configuration she was accustomed to use for communications.
She did not understand the technical aspects of radio well enough to diagnose her problem and was not sufficiently familiar with the radio gear to know all the options available to her. She had been taught to shift the receiver to the loop antenna when she wanted to take a bearing, but probably no one had ever explained to her how the loop also could be used in carrying on communications. Had she been aware of that option and listened on the loop for Itasca‘s voice signals on 3105 kHz, no doubt she would have heard the ship and been able to establish two-way communications.
The probability is very high that the failure of the receiving system to receive signals when using the fixed antenna was due either to a defective feed line between the receiver unit and the “send/receive” relay in the transmitter, or a defect in that relay itself. The odds are about 95 to 5 that the relay was at fault. It is considered therefore that a failure of that relay was the one single thing most responsible for the failure of the Earhart flight.
If it is assumed that the “peculiar signals” intercepted by Nauru and the PAA stations at Wake and Midway were in fact from the Earhart plane then the following may be deduced from the radio signals:
(a) The landing was fairly successful. The plane did not nose over or break up, otherwise the radio could not have been used.
(b) The landing was not in the open sea. Had it been, enough salt water would have seeped in to enter the wiring and disable the radio transmitting gear in a relatively short time.
(c) Earhart survived the landing. She was heard by the Nauru operator long after the plane would have run out of gas.
(d) Noonan survived. A man’s voice was distinctly heard on the “peculiar signal” by Midway. It was unintelligible.
(e) Either Earhart or Noonan, or both, were alive and with the plane at least until 0948 July 5, 1937 GCT time and date. The “peculiar signals” were last heard then.
(f) The “peculiar signals” probably were coming from the eastern or southeastern part of the Marshall Islands. (End of Almon Gray’s “Amelia Earhart and Radio.”)
Bill Prymak’s note: Capt. Gray, USNR (Ret.) received his Commercial Radio Operator License in 1930, and went with Pan American in 1935, when they started the trans-Pacific service. He became Flight Radio Officer on China Clipper type aircraft, and later was promoted to Assistant Superintendent of Communication in 1937.
The AMELIA EARHART SOCIETY finds the above radio analysis of the last flight to be one of the finest pieces of work ever presented on this subject.
Editor’s note: We should remember that in considering this analysis of Earhart’s final flight, Almon Gray took the position that the fliers were actually trying to reach Howland Island, and that all their actions were directed toward that goal. If Amelia and Noonan were not trying to reach Howland, but were engaged in some sort of covert operation, which certainly cannot be ruled based on our limited knowledge of what transpired during those final hours, then many of Gray’s findings become largely irrelevant.