Failure to communicate - Revision history

Moleski: /* Abandonment of CW (Morse Code) */

2026-10-27T12:59:46Z

Abandonment of CW (Morse Code)

← Older revision		Revision as of 12:59, 27 October 2026
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	"On enquiry Miss Earhart and Captain Noonan advised that they entirely depended on radio telephone reception as neither of them were able to read morse at any speed but could recognise an individual letter sent several times. This point was again mentioned by both of them later when two different sets at Lae were used for listening in for time signals."<ref>[http://www.tighar.org/Projects/Earhart/Documents/Chater_Report.html The Chater Report.]</ref>		"On enquiry Miss Earhart and Captain Noonan advised that they entirely depended on radio telephone reception as neither of them were able to read morse at any speed but could recognise an individual letter sent several times. This point was again mentioned by both of them later when two different sets at Lae were used for listening in for time signals."<ref>[http://www.tighar.org/Projects/Earhart/Documents/Chater_Report.html The Chater Report.]</ref>

	"Miss Earhart and Captain Noonan spent a considerable time in the radio office and as previously mentioned it was learned that neither of them could read morse at any speed but could only distinguish letters made individually slowly and repeated often; in that case their direction finding apparatus would be useless or misleading unless they were taking a bearing on a station using radiophone which could give the station position on voice. We understand the ''Itasca'' was to do this but if the plane was unable to pick up the ''Itasca'' it is doubtful if the ~~drection~~ finder would be any use to her."<ref>[http://www.tighar.org/Projects/Earhart/Documents/Chater_Report.html The Chater Report.]</ref>		"Miss Earhart and Captain Noonan spent a considerable time in the radio office and as previously mentioned it was learned that neither of them could read morse at any speed but could only distinguish letters made individually slowly and repeated often; in that case their direction finding apparatus would be useless or misleading unless they were taking a bearing on a station using radiophone which could give the station position on voice. We understand the ''Itasca'' was to do this but if the plane was unable to pick up the ''Itasca'' it is doubtful if the direction finder would be any use to her."<ref>[http://www.tighar.org/Projects/Earhart/Documents/Chater_Report.html The Chater Report.]</ref>

	=== Removal of equipment ===		=== Removal of equipment ===

Moleski: /* Apparent ignorance of the limitations of her equipment */

2015-03-06T22:29:09Z

Apparent ignorance of the limitations of her equipment

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	:...Report in English, not code, especially while flying. Will broadcast hourly quarter past hour GCT. ...		:...Report in English, not code, especially while flying. Will broadcast hourly quarter past hour GCT. ...
	::''Now she plans just one broadcast per hour.''		::''Now she plans just one broadcast per hour.''

			==== A possible explanation ====

			:; Elgen M. and Marie K. Long, ''Amelia Earhart: The Mystery Solved,'' p. 116.

			:: By pure happenstance the first three bands of the radio receiver and the direction-finder loop were closely matched, and the direction-finder loop could obtain a bearing on bands 1, 2, and 3. However, the frequencies of the Bendix receiver's bands 4 and 5 were completely out of the design range of the direction-finder, and the loop could not process the signals to obtain bearings. But because both the loop coupler band selector and the Bendix receiver were marked with bands 1 to 5, Earhart thought she could take a radio bearing with her direction-finder loop on any signal between 200 and 10,000 kilocycles. She could not. Without Manning, the information provided earlier by the Bendix representative, Cyril Remmlein, could not be conveyed to Earhart. None of the radiomen was aware of Earhart's mistaken assumption.

	=== Earhart unclear on the concept of what ''Itasca'' needed ===		=== Earhart unclear on the concept of what ''Itasca'' needed ===

Moleski: /* Failure to anticipate difficulties of finding a minimum */

2013-01-21T01:48:34Z

Failure to anticipate difficulties of finding a minimum

← Older revision		Revision as of 01:48, 21 January 2013
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	=== Failure to anticipate difficulties of finding a minimum ===		=== Failure to anticipate difficulties of finding a minimum ===

			On July 1, Earhart tried to use her [[loop antenna]] to [[Failed direction finding test in Lae\|take a bearing on the airfield at Lae.]]

			:; [[Ric Gillespie]], ''[[Finding Amelia]]'', p. 74

			:: During the test flight, Earhart found she could receive Lae’s signal, but the intensity of the sound did not change when she rotated the loop. In the terminology of the time, she could not 'get a minimum,' and so could not get a bearing on the sending station. The problem was that although the radio receiver could pick up the signal and she could hear the tone in her headphones, the direction-finding aspect of the system could not respond to such a high frequency. Amelia, however, decided that the test had failed because the airplane was too close to the station and the signal was too strong.

			The onboard direction-finding system failed again two days later on the last flight.

	:1928 GMT: "KHAQQ calling ''Itasca'' we are circling [?] but cannot hear you go ahead on 7500 with a long count either now or on the schedule time on 1/2 hour"		:1928 GMT: "KHAQQ calling ''Itasca'' we are circling [?] but cannot hear you go ahead on 7500 with a long count either now or on the schedule time on 1/2 hour"
	:1930 GMT: "KHAQQ calling ''Itasca'' we received your signals but unable to get a minimum. Please take bearing on us and answer 3105 with voice." Another radioman reports this message as: "Amelia on again at 0800 [local time] says hears us on 7.5 megs go ahead on 7500 again."		:1930 GMT: "KHAQQ calling ''Itasca'' we received your signals but unable to get a minimum. Please take bearing on us and answer 3105 with voice." Another radioman reports this message as: "Amelia on again at 0800 [local time] says hears us on 7.5 megs go ahead on 7500 again."

Moleski: /* Inadequate coordination */

2012-04-15T14:35:13Z

Inadequate coordination

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	::ASK ONTARIO BROADCAST LETTER N FOR FIVE MINUTES TEN MINUTES AFTER HOUR GMT FOUR HUNDRED KCS WITH OWN CALL LETTERS REPEATED TWICE END EVERY MINUTE.		::ASK ONTARIO BROADCAST LETTER N FOR FIVE MINUTES TEN MINUTES AFTER HOUR GMT FOUR HUNDRED KCS WITH OWN CALL LETTERS REPEATED TWICE END EVERY MINUTE.
	:This message could indicate that Earhart realized that she had no way to request [[Ontario]] to transmit the desired signal, so she changed the procedure from "on request" to "broadcast". This would have fixed the problem had the message been relayed to the Ontario. But there's no record of Black having relayed the message to the Ontario. The message was relayed from Earhart in Lae to Black on the ''Itasca'' via the Navy radio station at Tutuila, so it is possible that Tutuila took the initiative and relayed the message directly to the Ontario - - although there is no record of that having happened.		:This message could indicate that Earhart realized that she had no way to request [[Ontario]] to transmit the desired signal, so she changed the procedure from "on request" to "broadcast". This would have fixed the problem had the message been relayed to the Ontario. But there's no record of Black having relayed the message to the Ontario. The message was relayed from Earhart in Lae to Black on the ''Itasca'' via the Navy radio station at Tutuila, so it is possible that Tutuila took the initiative and relayed the message directly to the Ontario - - although there is no record of that having happened.

			:: ''N.B. In this next paragraph, Brandenburg talks about a suspicion that Earhart's [[direction finding]] system may have been incapacitated on takeoff at Lae. His line of reasoning is not given here, but it may involve assumptions about the use of the [[dorsal antenna]] in conjunction with the [[loop antenna]]. The sole point of quoting this material is to call attention to the inadequate communications between Earhart and the <u>[[Ontario]]</u>.''

	:In any case, it would be reasonable for Earhart to assume that the second message was relayed to the Ontario, and that the Ontario would be broadcasting the requested signal on the requested schedule. If Ontario did get the message, the broadcast would have occurred and if, as we suspect, Earhart's DF ([[direction finding]]) gear was rendered inoperable on [[lost antenna\|takeoff at Lae]], she would not have been able to get a bearing on the Ontario--and she could have turned back to Lae. If Ontario did not get the message, the signal expected by Earhart in her second message would not have been sent by Ontario, and Earhart would have heard nothing. In this case, as well, Earhart would have had a warning that her DF gear wasn't working, and could have turned back to Lae.		:In any case, it would be reasonable for Earhart to assume that the second message was relayed to the Ontario, and that the Ontario would be broadcasting the requested signal on the requested schedule. If Ontario did get the message, the broadcast would have occurred and if, as we suspect, Earhart's DF ([[direction finding]]) gear was rendered inoperable on [[lost antenna\|takeoff at Lae]], she would not have been able to get a bearing on the Ontario--and she could have turned back to Lae. If Ontario did not get the message, the signal expected by Earhart in her second message would not have been sent by Ontario, and Earhart would have heard nothing. In this case, as well, Earhart would have had a warning that her DF gear wasn't working, and could have turned back to Lae.

Rickerjones: /* References */ add llink to Air Navigation

2011-03-07T17:18:08Z

References: add llink to Air Navigation

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	== References ==		== References ==
	<references/>		<references/>

			==Related==
			* [[Air Navigation: State of the Art in 1937]]


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Thomas: italicize ships' names

2011-02-26T19:04:28Z

italicize ships' names

Show changes

Thomas: correct TTracks URL

2011-02-21T13:05:06Z

correct TTracks URL

← Older revision		Revision as of 13:05, 21 February 2011
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	=== Preference for voice communication (telephony) ===		=== Preference for voice communication (telephony) ===

	Earhart and Noonan were ahead of their time in asking that the ''Itasca'' communicate with them solely via [[voice\|voice transmissions.]] That is now the worldwide norm for aircraft. In 1937, the worldwide norm was [[Morse code]] transmitted on [[continuous wave]] (CW) or [[MCW\|modified continuous wave]] (MCW). The ''Itasca'' could not transmit voice on all frequencies (e.g., 7500 kHz).<ref>[http://www.tighar.org/TTracks/12_2/logjam.html "Log Jam."]</ref>		Earhart and Noonan were ahead of their time in asking that the ''Itasca'' communicate with them solely via [[voice\|voice transmissions.]] That is now the worldwide norm for aircraft. In 1937, the worldwide norm was [[Morse code]] transmitted on [[continuous wave]] (CW) or [[MCW\|modified continuous wave]] (MCW). The ''Itasca'' could not transmit voice on all frequencies (e.g., 7500 kHz).<ref>[http://www.tighar.org/Publications/TTracks/12_2/logjam.html "Log Jam."]</ref>

	"As the result of a talk with Mr. E. Chater and Mr. Balfour the Lae radio operator it is very apparent that the weak link in the combination was the crew’s lack of expert knowledge of radio. Their morse was very slow and they preferred to use telephony as much as possible."<ref>[http://www.tighar.org/Projects/Earhart/Documents/Collopy_Letter.html James A. Collopy]</ref>		"As the result of a talk with Mr. E. Chater and Mr. Balfour the Lae radio operator it is very apparent that the weak link in the combination was the crew’s lack of expert knowledge of radio. Their morse was very slow and they preferred to use telephony as much as possible."<ref>[http://www.tighar.org/Projects/Earhart/Documents/Collopy_Letter.html James A. Collopy]</ref>

Moleski: /* References */

2010-06-09T17:03:00Z

References

← Older revision		Revision as of 17:03, 9 June 2010
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	<!-- Please leave this category marker at the bottom. You may add this article to other categories if you wish -->		<!-- Please leave this category marker at the bottom. You may add this article to other categories if you wish -->
			[[Category:Navigation]]
			[[Category:Final Flight]]
	[[Category:Radio considerations]]		[[Category:Radio considerations]]
	~~[[Category:Final Flight]]~~

Moleski: /* References */

2010-01-10T20:43:36Z

References

← Older revision		Revision as of 20:43, 10 January 2010
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	<!-- Please leave this category marker at the bottom. You may add this article to other categories if you wish -->		<!-- Please leave this category marker at the bottom. You may add this article to other categories if you wish -->
	[[Category:Radio considerations]]		[[Category:Radio considerations]]
			[[Category:Final Flight]]

Moleski: /* Removal of equipment */

2009-10-27T20:48:59Z

Removal of equipment

← Older revision		Revision as of 20:48, 27 October 2009
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	500 kHz was a universal [[frequency]] used by ships at sea for two purposes: emergency calls and for making contact with other stations (once contact was made, the subsequent transmissions would take place on a different frequency). As a matter of convention, all of the traffic on 500 kHz was conducted in [[Morse code]] using [[continuous wave]] or [[modulated continuous wave]] transmission.		500 kHz was a universal [[frequency]] used by ships at sea for two purposes: emergency calls and for making contact with other stations (once contact was made, the subsequent transmissions would take place on a different frequency). As a matter of convention, all of the traffic on 500 kHz was conducted in [[Morse code]] using [[continuous wave]] or [[modulated continuous wave]] transmission.

	During the [[first around-the-world attempt]], [[Manning]] was equipped and trained to handle communication on 500 kHz. When he was unwilling or unable to participate in the second attempt, Earhart and Noonan decided to rely solely on [[voice transmission]] (radiotelephony) on 3105 kHz and 6210 kHz. The 500 kHz equipment was then just dead weight and some (or all?) of it was removed to save weight (and thereby gain range).		During the [[first around-the-world attempt]], [[Manning]] was equipped and trained to handle communication on 500 kHz. When he was unwilling or unable to participate in the second attempt, Earhart and Noonan decided to rely solely on [[voice\|voice transmission]] (radiotelephony) on 3105 kHz and 6210 kHz. The 500 kHz equipment was then just dead weight and some (or all?) of it was removed to save weight (and thereby gain range).

	==== Trailing antenna ====		==== Trailing antenna ====