| Signals |
The Signal Identifier number is divided into these elements:
| Day |
Time |
Source |
| 5 |
0948 |
WD |
| (July) |
24hr |
List |
|
121
| Identifier |
50948WD |
| Z Time/Date |
0948-0952 July 5 |
| Local Time/Date |
0948-0952 Z July 5 |
| Gardner Time/Date |
2248-2252 July 4 |
| Agency/Person |
Pan American Airways Radio direction finding station |
| Location |
Wake Island |
| Freq (kHz) |
3105 |
| Content |
At 09:48 a voice signal of good intensity and well
modulated 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 09:50 the carrier strength fell
off sharply with the wavering more noticeable than ever. At 09:52 it went off
completely. |
| Source |
Pan Am memo from Operator in Charge, Communications,
Wake, to Division Superintendent, Communications, Alameda dated July 11,
1937. |
| Probability |
0.001 |
| Qual Factors |
Earhart’s transmitter was the only central Pacific Source
of voice signals on 3105 kHz. |
| Credibility |
Credible |
|
122
| Identifier |
51015CV |
| Z Time/Date |
1015 July 5 |
| Local Time/Date |
0215 PST July 5 |
| Gardner Time/Date |
2315 July 4 |
| Agency/Person |
COMFRANDIV |
| Location |
San Francisco |
| Freq (kHz) |
3105 |
| Content |
This was one of the series of carrier signals, seemingly
on an hourly schedule, heard at COMFRANDIV since 0730Z. |
| Source
|
MSG9.PDF, p. 394; Finding Amelia, pp 151 et seq. |
| Probability |
0.0017 |
| Qual Factors |
This signal appears to be one of those responding to the
0730Z KGMB broadcast to Earhart, heard at COMFRANDIV on an apparent hourly
schedule, at 15 minutes past each hour. This is the same schedule that
Earhart declared prior to departing Lae, New Guinea, enroute to Howland
Island. |
| Credibility |
Credible |
|
123
| Identifier |
51105HD |
| Z Time/Date |
1105 July 5 |
| Local Time/Date |
0035 HST July 5 |
| Gardner Time/Date |
0005 July 5 |
| Agency/Person |
Itasca detachment |
| Location |
Howland Island |
| Freq (kHz) |
3105 |
| Content |
An unidentified continuous wave signal was heard. No call
sign was heard. A direction finder bearing of either south-southeast or
north-northwest was obtained using a magnetic compass. The bearing ambiguity
was due to ionospheric multipath interference – “night effect.” The frequency
was reported as “slightly above” 3105 kHz. |
| Source |
MSG9.PDF, p. 389 |
| Probability |
0.78 |
| Qual Factors |
The bearing line, although directionally ambiguous, lay
approximately along the line between Howland Island and Gardner. The nearest
land north-northwest of Howland is Wake Island (1500 nmi); the Pan American
Airways direction finder station there would not be transmitting on any
frequency near 3105 kHz. The next nearest land beyond Wake is in the Kuril
Islands (about 3300 nmi), but there were no stations in that vicinity
operating on a frequency near 3105 kHz. This suggests that the signal
originated from a source south-southeast of Howland. Earhart’s transmitter
was the only plausible source in that direction. |
| Credibility |
Credible |
|
124
| Identifier |
51115CV |
| Z Time/Date |
1115 July 5 |
| Local Time/Date |
0315 PST July 5 |
| Gardner Time/Date |
0015 July 5 |
| Agency/Person |
COMFRANDIV |
| Location |
San Francisco |
| Freq (kHz) |
3105 |
| Content |
A carrier signal, one of the series of signals seemingly
on an hourly schedule since 0730Z. |
| Source |
MSG9.PDF, p. 394; Finding
Amelia, pp 151 et seq. |
| Probability |
0.0038 |
| Qual Factors |
This signal appears to be one of those responding to the
0730Z KGMB broadcast to Earhart, heard at COMFRANDIV on an apparent hourly
schedule, at 15 minutes past each hour. This was the same transmission
schedule that Earhart declared prior to departing Lae, New Guinea, enroute to
Howland Island. |
| Credibility |
Credible. |
|
125
| Identifier |
51130WE |
| Z Time/Date |
1130-1230 July 5 |
| Local Time/Date |
0100-0200 July 5 |
| Gardner Time/Date |
0030-0130 July 5 |
| Agency/Person |
Navy radio station Wailupe |
| Location |
Oahu |
| Freq (kHz) |
Not given. Assume 3105. |
| Content |
The following Morse code transmission, consisting of
fragmentary phrases, with extremely poor keying, was copied by three Navy
operators: “281 NORTH HOWLAND CALL KHAQQ BEYOND NORTH DONT HOLD WITH US MUCH
LONGER ABOVE WATER SHUT OFF” |
| Source |
MSG9.PDF, p. 388; Finding Amelia, p. 164. |
| Probability |
0.006 |
| Qual Factors |
The text of this fragmented message has been thoroughly analyzed
by TIGHAR, but no conclusive reconstruction was possible because neither the
boundaries of the fragments, nor the length of gaps between fragments, are
known. The characterization of the keying as “extremely poor” is consistent
with Earhart or Noonan – neither of whom was proficient at Morse
– having composed a message by writing dots and dashes on paper, then
transmitting it by using the microphone push-to-talk button to key the transmitter.
Fragmentation also could have resulted from signal fading. The phrase “281
North Howland” was misinterpreted by Itasca to mean the plane was 281 miles north of Howland – which was impossible
since the plane would be on water and unable to transmit. The Pan Am RDF
station at Mokapu Point heard weak carrier signals on 3105 kHz during the
night, some of which could have been this transmission. Mokapu got an
approximate bearing of 215° on a carrier signal at 1225 Z. On balance, the
evidence weighs in favor of the Wailupe signal being from Earhart. |
| Credibility |
Credible |
|
126
| Identifier |
51200ME |
| Z Time/Date |
1200 July 5 |
| Local Time/Date |
2200 July 5 |
| Gardner Time/Date |
0100 July 5 |
| Agency/Person |
Unnamed ham radio operator |
| Location |
Melbourne, Australia |
| Freq (kHz) |
3105 (assumed) |
| Content |
The Melbourne ham heard a “strange” signal at 10 p.m.
Melbourne time on Monday July 5, but did not perceive until the caller
“signed off” that it was “Mrs. Putnam,” i.e. Earhart. The ham reported the
signal to local civil aviation authorities. |
| Source |
Melbourne, Australia, newspaper “The Argus,” Saturday
July 10, 1937. |
| Probability |
0.002 |
| Qual Factors |
This signal was heard during the same period as the signal
heard at Wailupe above. The “strange” aspect of the signal would be
consistent with the fragmentary phases and extremely poor keying reported by
the Wailupe operators. The “sign off” reported by the Melbourne ham
apparently consisted of the call letters KHAQQ heard at Wailupe. There is no
basis for believing this was a hoax. The evidence suggests this was a
concurrent reception of the signal heard at Wailupe. |
| Credibility |
Credible |
|
127
| Identifier |
51213IA |
| Z Time/Date |
1213 July 5 |
| Local Time/Date |
0043 July 5 |
| Gardner Time/Date |
1343 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
7500 |
| Content |
Itasca called Earhart in Morse code. |
| Source |
RADREST.PDF, p. 177 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
128
| Identifier |
51215CV |
| Z Time/Date |
1215 July 5 |
| Local Time/Date |
0415 PST July 5 |
| Gardner Time/Date |
0115 July 5 |
| Agency/Person |
COMFRANDIV |
| Location |
San Francisco |
| Freq (kHz) |
3105 |
| Content |
A carrier signal, one of the series of signals seemingly
on an hourly schedule since 0730Z. |
| Source |
MSG9.PDF, p. 394; Finding
Amelia |
| Probability |
0.0038 |
| Qual Factors |
This signal appears to be one of those responding to the
0730Z broadcast to Earhart, heard at COMFRANDIV on an apparent hourly
schedule, at 15 minutes past each hour. This was the same transmission
schedule that Earhart declared prior to departing Lae, New Guinea, enroute to
Howland Island. |
| Credibility |
Credible. |
|
129
| Identifier |
51223WD |
| Z Time/Date |
1223-1236 July 5 |
| Local Time/Date |
1223-1236 Z July 5 |
| Gardner Time/Date |
0123-0136 July 5 |
| Agency/Person |
Pan American Airways Radio direction finding station |
| Location |
Wake Island |
| Freq (kHz) |
3105 |
| Content |
A very unsteady voice modulated carrier was observed at
1223Z, which lasted until 12:36 Z. Wake was able to get an approximate
bearing of 144 degrees, believed to be reasonably accurate. The signal began
at QSA 5 (a very strong signal)
and gradually reduced to QSA 2 (moderate strength) by 12:36Z. |
| Source |
Pan Am memo from Operator in Charge, Communications,
Wake, to Division Superintendent, Communications, Alameda dated July 11, 1937. |
| Probability |
0.0006 |
| Qual Factors |
It was not plausible for Earhart to key her transmitter
for 13 minutes. However, this could have been a series of short transmissions
separated by brief intervals, appearing as part of the perceived
unsteadiness. The fact that the voice was not readable could be explained by
severe multipath fading interference. It is unlikely that Wake was hearing a
west coast aircraft, due to the distance – about 4,000 miles –
and the poor signal propagation from the west coast, which was worse than the
propagation from Gardner by a factor of about 10,000. Wake described the
characteristics of the signal as identical to those of a signal heard the
previous night; that signal was heard during a period when Itasca was not transmitting. Earhart’s
transmitter was the only central Pacific source of voice signals on 3105 kHz,
other than Itasca. |
| Credibility |
Credible |
|
130
| Identifier |
51230PN |
| Z Time/Date |
1230 and 1251 July 5 |
| Local Time/Date |
0430 and 0451 PST July 5 |
| Gardner Time/Date |
0130 and 0151 July 5 |
| Agency/Person |
Karl Pierson, Radio engineer and Ham radio operator |
| Location |
Los Angeles, CA |
| Freq (kHz) |
Not given. 3105 kHz assumed |
| Content |
Pierson claimed to have heard Itasca asking Earhart to send 4 dashes, at the times above, and
claimed to hear 3 long dashes immediately following each Itasca transmission. Pierson said each dash “ended in a ripple,
as though the plane’s batteries were dead and the motor generator was being
run to furnish transmission power.” |
| Sources |
New York Herald
Tribune, July 6, 1937, p. 2; MSG9.PDF, p. 394; RADREST.PDF, p. 178 and p.
180; Finding Amelia, p. 171. |
| Probability |
0.00000005 at Los Angeles; 0.00009 at COMFRANDIV. |
| Qual Factors |
Itasca called Earhart on 3105 kHz at 1223Z and 1254Z, but not
at 1251Z. Pierson could have heard the Itasca calls, and his clock could have been a few minutes slow. However, COMFRANDIV
had radio operators listening for Earhart signals on 6 receivers, connected
to 2 high-gain rhombic antennas. COMFRANDIV heard dash signals, apparently
from Earhart, on 3105 kHz during the night, but Pierson did not report
hearing any of those signals. The propagation paths from Gardner to San
Francisco and Los Angeles were virtually identical. The fact that COMFRANDIV,
listening with highly sensitive antennas heard signals that Pierson did not
hear, but did not hear the two signals Pierson claimed to have heard,
suggests that Pierson was perpetrating a hoax. |
| Credibility |
Not Credible. |
|
131
| Identifier |
51235IA |
| Z Time/Date |
1235 July 5 |
| Local Time/Date |
0105 July 5 |
| Gardner Time/Date |
0135 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
This signal is not in the Itasca log. The Pan Am station at Midway heard Itasca calling Earhart (presumably in
voice), but no response was heard. |
| Source |
RADREST.PDF, p. 179 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
132
| Identifier |
51240IA |
| Z Time/Date |
1240 July 5 |
| Local Time/Date |
0110 July 5 |
| Gardner Time/Date |
0140 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
Itasca called Earhart in voice. A minute later, Howland Island
heard Itasca say “give us 4 long
dashes if you hear us.” |
| Source |
RADREST.PDF, p. 179 and p.180 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
133
| Identifier |
51245IA |
| Z Time/Date |
1245 July 5 |
| Local Time/Date |
0115 July 5 |
| Gardner Time/Date |
0145 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
Itasca called Earhart on 3105. (Assumed in voice). |
| Source |
RADREST.PDF, p. 180 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
134
| Identifier |
51250IA |
| Z Time/Date |
1250 July 5 |
| Local Time/Date |
0120 July 5 |
| Gardner Time/Date |
0150 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
Howland Island heard Itasca calling Earhart on 3105, and giving unspecified instructions. |
| Source |
RADREST.PDF, p. 180 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
135
| Identifier |
51254IA |
| Z Time/Date |
1254 July 5 |
| Local Time/Date |
0124 July 5 |
| Gardner Time/Date |
0154 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
Itasca called Earhart. |
| Source |
RADREST.PDF, p. 180 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
136
| Identifier |
51300IA |
| Z Time/Date |
1300 July 5 |
| Local Time/Date |
0130 July 5 |
| Gardner Time/Date |
0200 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
7500 |
| Content |
Itasca called Earhart in Morse code. |
| Source |
RADREST.PDF, p. 180 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
137
| Identifier |
51305CV |
| Z Time/Date |
1305 July 5 |
| Local Time/Date |
0505 PST July 5 |
| Gardner Time/Date |
0205 July 5 |
| Agency/Person |
COMFRANDIV |
| Location |
San Francisco |
| Freq (kHz) |
3105 |
| Content |
A carrier signal, one of the series of signals seemingly
on an hourly schedule since 0730Z. |
| Source |
MSG9.PDF, p. 394; Finding
Amelia. |
| Probability |
0.000000075 |
| Qual Factors |
This signal appears to be one of those responding to the
0730Z KGMB broadcast to Earhart, heard at COMFRANDIV on an apparent hourly
schedule, at 15 minutes past each hour. This was the same transmission
schedule that Earhart declared prior to departing Lae, New Guinea, enroute to
Howland Island. It is plausible that this was the last signal of this series
heard at COMFRANDIV because the propagation path from Gardner faded out at
1400Z. |
| Credibility |
Credible. |
|
138
| Identifier |
51350PU |
| Z Time/Date |
1350 July 5 |
| Local Time/Date |
0320 HST July 5 |
| Gardner Time/Date |
0250 July 5 |
| Agency/Person |
Pan American Airways Radio direction finding station |
| Location |
Mokapu Point, Oahu |
| Freq (kHz) |
3105 |
| Content |
Carrier on again briefly, not long enough to get a
bearing. |
| Source |
Pan Am memo from Section Supervisor, Communications,
Honolulu to Division Superintendent, Communications, Alameda dated July 10,
1937. |
| Probability |
0.0097 |
| Qual Factors |
This signal could have been sent by Earhart, on battery
power, or it could have been from a west coast aircraft. There is not
sufficient information to decide the credibility of this signal. |
| Credibility |
Uncertain |
|
139
| Identifier |
51417CV |
| Z Time/Date |
1417-1419 July 5 |
| Local Time/Date |
0617-0619 PST July 5 |
| Gardner Time/Date |
0317-0319 July 5 |
| Agency/Person |
COMFRANDIV |
| Location |
San Francisco |
| Freq (kHz) |
3105 |
| Content |
“NRUI” (Itasca’s call sign) was heard in Morse code at 1417Z (0617 PST), followed almost
immediately by 4 dashes of approximately 4 to 5 seconds duration, with spaces
of the same length. Shortly afterward a carrier was heard, and a man’s voice.
The only distinguishable English was the letter “I,” at the end of the
transmission, which lasted approximately 2 minutes. |
| Source |
MSG9.PDF, p. 394 |
| Probability |
0.007 (Morse code); 0.000025 (voice) |
| Qual Factors |
Itasca did not call Earhart on 3105 between 1254Z and 2130Z. Although
Earhart and Noonan were not proficient in Morse code, either could send NRUI
in Morse code if the message was composed and written down before sending. “NRUI”
in Morse is short enough for “clean” transmission by pressing the microphone
push-to-talk button, without the sender’s finger becoming fatigued and altering
the rhythm of the signal. A plausible scenario that fits the reported
information is that “NRUI” was sent in Morse to get Itasca’s attention,
followed by the dashes, then in voice “This is KHAQQ calling NRUI,” with only
the final “I” rising above the atmospheric noise at San Francisco. |
| Credibility |
Credible |
|
140
| Identifier |
51700CB |
| Z Time/Date |
1700Z (and unspecified subsequent times) July 5 |
| Local Time/Date |
1300 EDT July 5 |
| Gardner Time/Date |
0600 July 5 |
| Agency/Person |
Mrs. Ernest Crabb |
| Location |
Toronto, Canada |
| Freq (kHz) |
18630 |
| Content |
This reception was on the day after Mrs. Crabb heard
Earhart, and appears to be the same sort of fragmentary conversation that she
heard the previous day. |
| Source |
Toronto Daily Star,
July 5, 1937 and July 6, 1937 |
| Probability |
0.00004 |
| Qual Factors |
18630 kHz is the 6th harmonic of 3105 kHz. Mrs.
Crabb heard this signal on the same 20-tube shortwave receiver she used the
previous day. Given the similarity of this signal and the credibility of her
previous report, there is no reason to doubt the credibility of this signal,
which could have been sent on battery power. |
| Credibility |
Credible |
|
141
| Identifier |
52130IA |
| Z Time/Date |
2130 July 5 |
| Local Time/Date |
1000 July 5 |
| Gardner Time/Date |
1030 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
Itasca called Earhart in Morse code |
| Source |
RADREST.PDF, p. 188 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
142
| Identifier |
52130KK |
| Z Time/Date |
2130 to 2315 July 5 (Date uncertain; believed to be July
5 based on signal propagation and other factors) |
| Local Time/Date |
1630 to 1815 EST July 5 |
| Gardner Time/Date |
1030 to 1215 July 5 |
| Agency/Person |
Betty Klenck |
| Location |
St. Petersburg, Florida |
| Freq (kHz) |
24840 (4th harmonic of Earhart’s day frequency
– 6210 kHz). |
| Content |
See sources below. |
| Sources |
Research paper Betty’s Notebook, on TIGHAR website; research
paper Harmony and Power (revised), on TIGHAR website; Finding Amelia, p. 172. |
| Probability |
Varied from 0.0013 to 0.00000067 during the period |
| Qual Factors |
Betty was extensively interviewed by TIGHAR, and key
elements of her notebook relating to occult information – facts Betty
could not have known from sources other than what she heard on the radio –
have been validated. Details are available on the TIGHAR website. |
| Credibility |
Credible |
|
143
| Identifier |
52135IA |
| Z Time/Date |
2135 July 5 |
| Local Time/Date |
1005 July 5 |
| Gardner Time/Date |
1035 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
Itasca called Earhart in Morse code. |
| Source |
RADREST.PDF, p. 188 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
144
| Identifier |
52152IA |
| Z Time/Date |
2152 July 5 |
| Local Time/Date |
1022 July 5 |
| Gardner Time/Date |
1052 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
Itasca called Earhart in Morse code |
| Source |
RADREST.PDF, p. 188 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
145
| Identifier |
60606IA |
| Z Time/Date |
0606 July 6 |
| Local Time/Date |
1836 July 5 |
| Gardner Time/Date |
1906 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
Itasca called Earhart in voice; content unspecified. |
| Source |
RADREST.PDF, p. 192 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
146
| Identifier |
60610IA |
| Z Time/Date |
0610 July 6 |
| Local Time/Date |
1840 July 5 |
| Gardner Time/Date |
1910 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
unknown |
| Content |
Itasca requested Earhart to send 4 long dashes. |
| Source |
RADREST.PDF, p. 193 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
147
| Identifier |
60619IA |
| Z Time/Date |
0619 July 6 |
| Local Time/Date |
1849 July 5 |
| Gardner Time/Date |
1919 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
unknown |
| Content |
Itasca again requested Earhart to send 4 long dashes |
| Source |
RADREST.PDF, p. 193 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
148
| Identifier |
60630IA |
| Z Time/Date |
0630 July 6 |
| Local Time/Date |
1900 July 5 |
| Gardner Time/Date |
1930 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
unknown |
| Content |
Itasca called Earhart in Morse code |
| Source |
RADREST.PDF, p. 193 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
149
| Identifier |
60640IA |
| Z Time/Date |
0640 July 6 |
| Local Time/Date |
1910 July 5 |
| Gardner Time/Date |
1940 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
Itasca called Earhart in voice. |
| Source |
RADREST.PDF, p. 193 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
150
| Identifier |
60700IA |
| Z Time/Date |
0700 July 6 |
| Local Time/Date |
1930 July 5 |
| Gardner Time/Date |
2000 July 5 |
| Agency/Person |
Itasca |
| Location |
Central Pacific |
| Freq (kHz) |
3105 |
| Content |
Itasca called Earhart in voice |
| Source |
RADREST.PDF, p. 194 |
| Probability |
n/a |
| Qual Factors |
n/a |
| Credibility |
n/a |
|
|
