Signals July 4 |
The Signal Identifier number is divided into these elements:
Day |
Time |
Source |
4 |
0620 |
CC |
(July) |
24hr |
List |
- Identifiers in BLUE are TRANSMISSIONS to Earhart.
- Identifiers in RED are reported receptions that are judged to be NOT CREDIBLE.
- Identifiers in BLACK are reported
receptions the credibility of which are judged to be UNCERTAIN.
- Identifiers in GREEN are reported
receptions that are judged to be CREDIBLE.
|
|
48
Identifier |
4xxxxMY |
Z Time/Date |
Time(s) unknown, July 4 |
Local Time/Date |
Time(s) unknown, July 4 |
Gardner Time/Date |
Time(s) unknown, July 4 |
Agency/Person |
Ray Mahoney, radio amateur |
Location |
Cincinnati, Ohio |
Freq (kHz) |
unknown |
Content |
Mahoney said he heard Earhart “pleading for help” from a
position he assumed to be within 57 miles of Howland Island. He said “The
signals were weak, about all I could make out were the call letters of her
plane, that apparently had hit a reef or was near a reef.” He said he had
heard the distress signals at 10 minutes intervals throughout “yesterday,”
which was Saturday, July 3. |
Source |
Associated Press wire story in Gettysburg, PA, Times, July 5, 1937, p.2; Associated
Press wire story in Newark, OH, Advocate, July 5, 1937, p.1; Finding
Amelia, p.171. |
Probability |
Not computed because specific times and frequencies not
given. But continuous reception “throughout yesterday” on any given single
frequency was impossible. |
Qual Factors |
There is no reef within 57 miles of Howland. It would be
implausible for Earhart to transmit at 10 minute intervals “throughout
yesterday” since doing so would entail the risk of dropping the battery
charge below the level needed to start the engine, thus precluding future
radio transmissions. Furthermore, propagation conditions precluded receiving
signals during such a long period. |
Credibility |
Not credible |
|
49
Identifier |
40620CC |
Z Time/Date |
0620 to at least 0846 July 4 |
Local Time/Date |
1950 to at least 2216 HST July 3 |
Gardner Time/Date |
1920 to 2146 July 3 |
Agency/Person |
Coast Guard Commander, Hawaiian Sector (COMHAWSEC) |
Location |
Honolulu |
Freq (kHz) |
3105 |
Content |
COMHAWSEC advised Itasca that a weak carrier (unmodulated) signal had been heard on 3105 kHz, and that
the Pan American Airways direction finder station at Mokapu also heard the
signal but was unable to get a bearing on the source. |
Source |
MSG8.PDF, p. 351 |
Probability |
0.024 |
Qual Factors |
The signal could have originated at Gardner. However,
west coast aircraft can’t be ruled out since this time period was during
night there, and aircraft would be using 3105 kHz. There is insufficient
evidence to decide where the signal probably originated. |
Credibility |
Uncertain. |
|
50
Identifier |
40645IA |
Z Time/Date |
0645 July 4 |
Local Time/Date |
1915 July 3 |
Gardner Time/Date |
1945 July 3 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3110 kHz |
Content |
Itasca logged hearing a weak signal with possible voice
modulation on 3110 kHz. |
Source |
RADREST.PDF, p. 151 |
Probability |
0.87 |
Qual Factors |
There were no voice signal sources on 3110 kHz. Howland
Island received a credible signal from Earhart five minutes later. It is
possible that Itasca’s receiver was
not correctly set. |
Credibility |
Uncertain |
|
51
Identifier |
40650HD |
Z Time/Date |
0650 July 4 |
Local Time/Date |
2020 HST July 3 |
Gardner Time/Date |
1950 July 3 |
Agency/Person |
Amateur radio operator |
Location |
Howland Island |
Freq (kHz) |
3105 kHz. (Assumed. Not stated in report) |
Content |
The Howland amateur operator informed Itasca – in a delayed report at
09:46 Z on July 5 – that the amateur radio operator on Baker Island (30
miles south southeast of Howland) had heard Earhart with a strong and clear
signal, at the time shown above but did not state the content of the
transmission. |
Source |
RADREST.PDF, p. 174. (Note: the final phrase of this
record – in which the signal characteristics are given –
inadvertently appears as the first phrase of the record at the top of p.
175.) |
Probability |
0.96 |
Qual Factors |
The signal strength is consistent with a transmission
from Gardner. And the operator was unequivocal about hearing Earhart. |
Credibility |
Credible |
|
52
Identifier |
40653IA |
Z Time/Date |
0653 July 4 |
Local Time/Date |
1923 July 3 |
Gardner Time/Date |
1953 July 3 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3110 |
Content |
Itasca heard the same signal as #40650HD above, very weak. |
Source |
RADREST.PDF, p. 151 |
Probability |
0.96 |
Qual Factors |
There were no voice signal sources on 3110 kHz. Howland
Island received a credible signal from Earhart three minutes prior (Signal
51). It is possible that Itasca’s receiver was not correctly set. |
Credibility |
Uncertain |
|
53
Identifier |
40720BR |
Z Time/Date |
0720 July 4 |
Local Time/Date |
2020 July 3 |
Gardner Time/Date |
2020 July 3 |
Agency/Person |
Amateur radio operator Paul Yat Lum |
Location |
Baker Island |
Freq (kHz) |
3105 |
Content |
The Earhart plane was heard, signal Strength 4 (5 being
maximum), Readability 7 (10 being maximum). Details not given. The fact of the
reception was relayed to Itasca by
the Coast Guard detachment on Howland Island. |
Source |
RADREST.PDF, p. 174 and 175; Finding Amelia, p.134. |
Probability |
0.85 |
Qual Factors |
The signal source was positively identified as the
Earhart plane. |
Credibility |
Credible |
|
54
Identifier |
40833KU |
Z Time/Date |
0833 July 4 |
Local Time/Date |
2203 HST July 3 |
Gardner Time/Date |
2133 July 3 |
Agency/Person |
Radio Station KGU |
Location |
Honolulu |
Freq (kHz) |
750 |
Content |
KGU broadcast a message to Earhart, requesting her to transmit
on 500, 3105, or 6210 kHz. |
Source |
TIGHAR Earhart Project Research Paper “The Itasca Search.” |
Probability |
n/a |
Qual Factors |
n/a |
Credibility |
n/a |
|
55
Identifier |
40834PU |
Z Time/Date |
0834 July 4 |
Local Time/Date |
2204 July 3 |
Gardner Time/Date |
2134 July 3 |
Agency/Person |
Pan American Airways radio direction finding station |
Location |
Mokapu Point, Oahu |
Freq (kHz) |
3105 |
Content |
Immediately following the KGU broadcast at 0833Z, the Pan
American station at Mokapu heard a faint carrier on approximately 3105 kHz,
but the signal was too weak to distinguish any words. |
Source |
Memorandum from Pan American Airways Communications
Section Supervisor, Honolulu, to Division Superintendent, Communications,
Alameda dated July 10, 1937. |
Probability |
0.0009 |
Qual Factors |
The reception probability at Mokapu was consistent with
the signal description. Honolulu broadcast stations could be heard throughout
the central Pacific, and the fact that the signal came immediately after the
KGU request suggests this was Earhart responding. It is possible that this
carrier signal was from one of the Nicaraguan stations, but the preponderance
of positive qualitative factors weighs in favor of concluding that the signal
was from Earhart. |
Credibility |
Credible |
|
56
Identifier |
40850IA |
Z Time/Date |
0850 July 4 |
Local Time/Date |
2120 July 3 |
Gardner Time/Date |
2150 July 3 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
A weak carrier was heard, but no voice. Itasca heard this weak carrier
continuously until 1300Z on July 4. |
Source |
RADREST.PDF, p. 153, et seq. |
Probability |
0.91 |
Qual Factors |
Although the probability of receiving a signal from Gardner
was high, it is not plausible for Earhart to have her transmitter on the air
for such a long time. It is possible that Itasca was hearing the carrier of one of the Nicaraguan stations. |
Credibility |
Not credible |
|
57
Identifier |
40851IA |
Z Time/Date |
0851-0854 July 4 |
Local Time/Date |
2121-2124 July 3 |
Gardner Time/Date |
2151-2154 July 3 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
near 3105 |
Content |
Itasca heard two carrier signals, but no voice, near 3105
kHz on slightly different frequencies, one slightly stronger than other but
both very weak. |
Source |
RADREST.PDF, p. 152 |
Probability |
0.92 |
Qual Factors |
Not more than one of these signals could be from Earhart.
One or both could have originated in Nicaragua. There is not sufficient
evidence to conclude that either of these signals was from Earhart. |
Credibility |
Uncertain |
|
58
Identifier |
40854IA |
Z Time/Date |
0854-0929 July 4 |
Local Time/Date |
2124-2159 July 3 |
Gardner Time/Date |
2154-2229 July 3 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 (approximately) |
Content |
Heard one carrier continuously during this period. |
Source |
RADREST.PDF, p. 152 |
Probability |
0.92 |
Qual Factors |
It was not plausible for Earhart to key her transmitter
continuously for such a long period. Itasca could have been hearing one of the Nicaraguan stations. |
Credibility |
Not Credible |
|
59
Identifier |
40936IA |
Z Time/Date |
0936-0952 July 4 |
Local Time/Date |
2206-2222 July 3 |
Gardner Time/Date |
2236-2252 July 3 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 approximately |
Content |
Itasca still hears a continuous carrier near 3105 kHz, very weak,
in severe atmospheric noise. |
Source |
RADREST.PDF, p. 153 |
Probability |
0.92 |
Qual Factors |
It was not plausible for Earhart to key her transmitter
continuously for such a long period. Itasca could have been hearing one of the Nicaraguan stations. |
Credibility |
Not credible |
|
60
Identifier |
41000KB |
Z Time/Date |
1000 July 4 |
Local Time/Date |
2330 HST July 3 |
Gardner Time/Date |
2300 July 3 |
Agency/Person |
Broadcast station KGMB |
Location |
Honolulu |
Freq (kHz) |
1320 |
Content |
KGMB broadcast a message to Earhart requesting her to
transmit dashes. |
Source |
TIGHAR Earhart Project Research Paper “The Itasca Search.” |
Probability |
n/a |
Qual Factors |
n/a |
Credibility |
n/a |
|
61
Identifier |
41005IA |
Z Time/Date |
1005 to 1029 July 4 |
Local Time/Date |
2235 to 2259 July 3 |
Gardner Time/Date |
2305 to 2329 July 3 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Itasca still hears a carrier signal on 3105 kHz, but very weak now. |
Source |
RADREST.PDF, p. 152 |
Probability |
0.91 |
Qual Factors |
It was not plausible for Earhart to key her transmitter
continuously for 24 minutes. Itasca could have been hearing one of the Nicaraguan stations. |
Credibility |
Not credible |
|
62
Identifier |
41012PU |
Z Time/Date |
1012-1020 July 4 |
Local Time/Date |
2342-2350 HST July3 |
Gardner Time/Date |
2312-2320 July 3 |
Agency/Person |
Pan American Airways Radio direction finding station |
Location |
Mokapu Point, Oahu |
Freq (kHz) |
3105 |
Content |
Intermittent carrier signals were heard, but no voice. |
Source |
Pan Am memo from Section Supervisor, Communications,
Honolulu to Division Superintendent, Communications, Alameda dated July 10,
1937. |
Probability |
0.0082 |
Qual Factors |
The Pan Am description of this signal is vague, although
an Associated Press story of July 5 stated that Honolulu radio station KGMB
had requested Earhart to turn her transmitter on and off four times, and that
the Pan Am listening station at Mokapu Point had heard four distinct dashes
in response. The timing and characteristics of this signal might suggest it
was from Earhart, in response to the KGMB request, but the possibility that
the source was in Nicaragua cannot be ruled out. |
Credibility |
Uncertain |
|
63
Identifier |
41022PU |
Z Time/Date |
1022 July 4 |
Local Time/Date |
2352 HST July 3 |
Gardner Time/Date |
2322 July 3 |
Agency/Person |
Pan American Airways Radio direction finding station |
Location |
Mokapu Point, Oahu |
Freq (kHz) |
3105 |
Content |
Two long dashes – possibly voice transmissions –
were heard on 3105. |
Source |
Pan Am memo from Section Supervisor, Communications,
Honolulu to Division Superintendent, Communications, Alameda dated July 10,
1937. |
Probability |
0.0055 |
Qual Factors |
The timing of the dashes suggests they were sent by
Earhart in response to the 1000Z KGMB broadcast. Earhart was the only
plausible source of voice signals on 3105 kHz in the central Pacific. |
Credibility |
Credible |
|
64
Identifier |
41031PU |
Z Time/Date |
1031 July 4 |
Local Time/Date |
0001 July 4 |
Gardner Time/Date |
2331 July 3 |
Agency/Person |
Pan American Airways radio direction finding station |
Location |
Mokapu Point, Oahu |
Freq (kHz) |
3105 |
Content |
The U.S. Navy radio station at Wailupe, Oahu, heard a
carrier on the air for a short time, and heard a male voice say “31,” but the
rest of the transmission was unreadable. The Pan Am station heard a carrier
at the same time, but no voice. |
Source |
Memorandum from Pan Am Section Supervisor,
Communications, Honolulu to Division Superintendent, Communications, Alameda
dated July 10, 1937. Wailupe evidently passed this information by telephone
to Mokapu, and also to the Coast
Guard commander in Honolulu (COMHAWSEC), who relayed it to the Itasca. |
Probability |
0.004 |
Qual Factors |
Earhart’s transmitter was the only credible voice source
on 3105 kHz in the central Pacific. The timing of this signal suggests it
could be a response to the KGMB broadcast at 1000Z. |
Credibility |
Credible |
|
65
Identifier |
41031PU |
Z Time/Date |
1031-1100 July 4 |
Local Time/Date |
0001-0030 July 4 |
Gardner Time/Date |
2331-2400 July 3 |
Agency/Person |
Pan American Airways radio direction finding station |
Location |
Mokapu Point, Oahu |
Freq (kHz) |
3105 |
Content |
The carrier previously heard comes and goes, increasing
somewhat in strength, but atmospheric noise is getting much worse and
reception is still too poor to try a bearing. |
Source |
Memorandum from Pan Am Section Supervisor, Communications,
Honolulu to Division Superintendent, Communications, Alameda dated July 10,
1937. |
Probability |
0.0076 |
Qual Factors |
The timing of this signal, and its intermittent nature,
are consistent with dashes responding to the KGMB broadcast at 1000Z. But it
also is possible the source was a Nicaraguan station. |
Credibility |
Uncertain |
|
66
Identifier |
41035CC |
Z Time/Date |
1035 July 4 |
Local Time/Date |
0005 July 4 |
Gardner Time/Date |
2335 July 3 |
Agency/Person |
Coast Guard Commander, Hawaiian Sector (COMHAWSEC) |
Location |
Honolulu |
Freq (kHz) |
3105 |
Content |
COMHAWSEC informed Itasca that the Navy radio station at Wailupe, the Pan Am direction finding station
at Mokapu, and COMHAWSEC, all heard a carrier and voice on 3105 kHz at the
end of the KGMB broadcast requesting Earhart to send dashes. (Note: Pan Am
Mokapu said they did not hear voice.) |
Source |
MSG8.PDF, p. 351 |
Probability |
0.004 at Honolulu |
Qual Factors |
The timing of this signal, and its intermittent nature,
are consistent with dashes responding to the KGMB broadcast at 1000Z. Earhart’s
transmitter was the only plausible source of voice signals on this frequency
in the central Pacific. |
Credibility |
Credible |
|
67
Identifier |
41037IA |
Z Time/Date |
1037 to 1055 July 4 |
Local Time/Date |
2307 to 2329 July 3 |
Gardner Time/Date |
2337 to 2355 July 3 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 kHz |
Content |
Itasca still hears a continuous weak carrier on 3105 kHz. |
Source |
RADREST.PDF, p. 154 |
Probability |
0.44 |
Qual Factors |
This appears to be a continuation of the long-duration
carrier reported by Itasca above,
possibly from Nicaragua. It is not plausible for Earhart to have keyed her
transmitter continuously for 19 minutes. |
Credibility |
Not credible |
|
68
Identifier |
41057IA |
Z Time/Date |
1057 July 4 |
Local Time/Date |
2327 July 3 |
Gardner Time/Date |
2357 July 3 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Itasca hears a weak unreadable Morse code signal, shifting in
frequency, very close to 3105 kHz. |
Source |
RADREST.PDF, p. 154 |
Probability |
0.74 |
Qual Factors |
Neither Earhart nor Noonan was proficient in Morse code. Furthermore,
Earhart’s transmitter frequency was crystal-controlled, and did not drift. |
Credibility |
Not credible |
|
69
Identifier |
41059IA |
Z Time/Date |
1059 July 4 |
Local Time/Date |
2329 July 3 |
Gardner Time/Date |
2359 July 3 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Itasca still hears the weak carrier, shifting in frequency (Identifier
41012PU above), but the Morse code signal has stopped. |
Source |
RADREST.PDF, p. 155 |
Probability |
0.74 |
Qual Factors |
Earhart’s transmitter frequency was crystal-controlled,
and did not drift. |
Credibility |
Not credible |
|
70
Identifier |
41110PU |
Z Time/Date |
1110 July 4 |
Local Time/Date |
0040 July 4 |
Gardner Time/Date |
0010 July 4 |
Agency/Person |
Pan American Airways Radio direction finding station |
Location |
Mokapu Point, Oahu |
Freq (kHz) |
3105 |
Content |
A signal sounding like someone trying to send Morse code,
but nothing readable. |
Source |
Memorandum from Pan Am Section Supervisor,
Communications, Honolulu to Division Superintendent, Communications, Alameda
dated July 10, 1937. |
Probability |
0.0076 |
Qual Factors |
Neither Noonan nor Earhart was proficient in Morse code. This
signal could have been one of the Nicaraguan Morse code stations, with fading
causing the Morse characters to be unreadable. There is not enough evidence
to decide what the source was. |
Credibility |
Uncertain |
|
71
Identifier |
41114IA |
Z Time/Date |
1114-1115 July 4 |
Local Time/Date |
2344-2345 July 3 |
Gardner Time/Date |
0014-0014 July 4 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
General call (CQ) Morse code signals heard almost on top
of the carrier that Itasca has been hearing. The signal is very weak and
unreadable in severe atmospheric noise. |
Source |
RADREST.PDF, p. 155 |
Probability |
0.69 |
Qual Factors |
Neither Earhart nor Noonan was proficient in Morse code. Itasca evidently was hearing two Nicaraguan
stations, as discussed earlier in this catalog. |
Credibility |
Not credible |
|
72
Identifier |
41122IA |
Z Time/Date |
1122-1124 July 4 |
Local Time/Date |
2352-2354 July 3 |
Gardner Time/Date |
0022-0024 July 4 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Someone was sending with a high-speed Morse code key. The
words “unlimited” and “clear” were understood, but the remainder was
unreadable. |
Source |
RADREST.PDF, p. 155 |
Probability |
0.68 |
Qual Factors |
Neither Earhart nor Noonan was proficient in Morse, and
certainly could not transmit Morse code at high speed. The most likely source
was a Nicaraguan station. |
Credibility |
Not credible. |
|
73
Identifier |
41127IA |
Z Time/Date |
1127-1137 July 4 |
Local Time/Date |
2357-0007 July 3 - 4 |
Gardner Time/Date |
0027-0037 July 4 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Itasca still hears a continuous carrier on 3105 kHz. |
Source |
RADREST.PDF, p. 155 |
Probability |
0.68 |
Qual Factors |
It was not plausible for Earhart to key her transmitter
for such a long period. Itasca most
likely was hearing the carrier of one of the Nicaraguan stations. |
Credibility |
Not credible. |
|
74
Identifier |
41200CV |
Z Time/Date |
1200 July 4 |
Local Time/Date |
0400 July 4 |
Gardner Time/Date |
0100 July 4 |
Agency/Person |
COMFRANDIV |
Location |
San Francisco |
Freq (kHz) |
6210 |
Content |
COMFRANDIV told Itasca that a special monitoring station set up to listen for Earhart signals heard
a strong carrier, but not voice, on 6210 kHz for about 15 minutes. The signal
appeared to be coming from a westerly direction. |
Source |
MSG8.PDF, p. 352 |
Probability |
0.14 |
Qual Factors |
6210 kHz is the second harmonic of Earhart’s night frequency, 3105 kHz. But it is not plausible that Earhart would key her
transmitter for such a long period. COMFRANDIV said that the special monitor
station (MSG9.PDF, p. 394) used “diamond beam” antennas aimed at Honolulu. “Diamond
beam” is a generic term for a rhombic antenna, which has a diamond-shaped
physical geometry. Such antennas were used by press services for
communication with remote sites such as Hawaii. The COMFRANDIV monitor site
was at the Press Wireless company facility, which used rhombic antennas for
communication with Honolulu. A rhombic antenna is very sensitive to signals
arriving from the direction of its main axis, but also has sidelobes that can
receive signals from directions perpendicular to the antenna’s main axis. In
the case of the Press Wireless antennas, the sidelobes were pointed along the
west coast, hence this signal could have come from west coast aircraft. There
is not enough evidence to conclude that Earhart was the source. |
Credibility |
Uncertain |
|
75
Identifier |
41153CV |
Z Time/Date |
1153-1353 July 4 |
Local Time/Date |
0353-0553 PST July 4 |
Gardner Time/Date |
0053-0253 July 4 |
Agency/Person |
COMFRANDIV |
Location |
San Francisco |
Freq (kHz) |
3105 and 6210 |
Content |
COMFRANDIV told Itasca that for the past two hours, no signals were heard on 3105 kHz, but a weak
carrier signal of unspecified duration, with no modulation, was heard on 6210
kHz, apparently originating west of San Francisco, and that the signal
disappeared at 0150 GCT, i.e. Z time. |
Source |
MSG8.PDF, p. 352 |
Probability |
0.07 |
Qual Factors |
The timing of the 6210 kHz signal is vague. The start
time is not given, and the “0150 GCT” time is outside the period covered by
this report, and may be a garble. It is possible that the signal was from a
west coast source, and was received in sidelobes of the rhombic (“diamond
beam”) antennas at the COMFRANDIV special monitoring site. There is not
enough evidence to conclude that Earhart was the source. |
Credibility |
Uncertain. |
|
76
Identifier |
41200CC |
Z Time/Date |
1200 July 4 |
Local Time/Date |
0130 HST July 4 |
Gardner Time/Date |
0100 July 4 |
Agency/Person |
Coast Guard Commander, Hawaiian Section (COMHAWSEC) |
Location |
Honolulu |
Freq (kHz) |
3105 |
Content |
COMHAWSEC informed Itasca of hearing a carrier signal on “about 3105 kHz,” lasting one minute, with
speech identified as a man’s voice. No details given as to what was said. |
Source |
MSG8.PDF, p. 354 |
Probability |
0.0021 (Gardner); 0.0003 (west coast) |
Qual Factors |
Earhart’s transmitter was the only plausible source of
voice on or near 3105 kHz in the central Pacific. If this signal had
originated on the west coast, it almost certainly would have been heard by at
least one of the FAA stations there, required to listen on 3105 kHz. |
Credibility |
Credible |
|
77
Identifier |
41215WD |
Z Time/Date |
1215 July 4 |
Local Time/Date |
1215Z July 4 |
Gardner Time/Date |
0115 July 4 |
Agency/Person |
Pan American Airways radio direction finding station |
Location |
Wake Island |
Freq (kHz) |
3105 |
Content |
Wake heard an intermittent male voice, of “rather wobbly
characteristics.” Atmospheric noise prevented understanding what was said. At 1210Z, Wake heard
several unreadable voice signals near 3105 kHz, in noise. |
Source |
Memorandum from Operator in Charge, Wake, to Division
Superintendent, Communications, Alameda dated July 10, 1937. |
Probability |
0.000079 (Gardner);
less than 1 chance in a quadrillion for a signal from the west coast. |
Qual Factors |
Earhart’s transmitter was the only plausible source of
voice signals in the central Pacific. Given Wake’s distance from the U.S.
west coast, approximately 4,000 nautical miles, it is highly doubtful that
this signal was from a west coast aircraft. Itasca was not transmitting at this time. |
Credibility |
Credible |
|
78
Identifier |
41200DN |
Z Time/Date |
1200-1230 July 4 |
Local Time/Date |
0130-0200 HST July 4 |
Gardner Time/Date |
0100-0130 July 4 |
Agency/Person |
Mr. Donaldson |
Location |
Wahiawa, Oahu, Hawaii |
Freq (kHz) |
3105 (assumed) |
Content |
The Navy radio station at Wailupe received a report from
a Mr. Donaldson of Wahiawa, relayed by the Mutual Wireless Company office in
Wahiawa. Donaldson described several signals heard on his Zenith shortwave
receiver, on an unspecified frequency, at unspecified specified times between
1200Z and 1230Z. He said he heard a man’s voice say “31.05,” “31.07,” and
“KHAQQ,” and then “62.05,” and “help.” |
Source |
MSG8.PDF, p. 355; Finding
Amelia, p. 138 |
Probability |
0.0021 on 3105 kHz, and 0.18 on 6210 kHz |
Qual Factors |
Donaldson did not say what model receiver he used. He
gave the receiver dial index scale settings where he heard signals, but they
are meaningless without knowing the receiver model, since Zenith did not use
a common dial design for all models. It is possible that he heard Fred
Noonan, Earhart’s navigator, saying “3105,” which was garbled to “31.05”
during the relay, but there was no plausible reason for Noonan to say “3107”
since Earhart’s transmitter could not operate on that frequency. The “62.05”
that Donaldson reported could have been a garble of Earhart’s day frequency,
6210 kHz. KHAQQ was Earhart’s call sign, and the word “help” was plausible in
the circumstances. However, all this information was available from public
sources, and Donaldson’s report could be a hoax. Although it is possible that
Donaldson heard the same signals heard by COMHAWSEC (Identifier 41110PU above) and Wake Island Identifier 41114IA above), there is no evidence
corroborating Donaldson’s claim. |
Credibility |
Uncertain |
|
79
Identifier |
41330MC |
Z Time/Date |
1330 July 4 |
Local Time/Date |
0530 PST July 4 |
Gardner Time/Date |
0230 July 4 |
Agency/Person |
Walter McMenamy, Karl Pierson and “Bo” McKneely |
Location |
Los Angeles |
Freq (kHz) |
6210 |
Content |
Pearson said “We heard nothing decipherable during the
night, and at 5:30 (8:30 am Chicago time) the carrier waive faded out. Just
before that we heard a voice definitely that of a woman and sounding like the
voice I had heard more clearly yesterday.” “McMenamy has said he was familiar
with Miss Earhart’s radio voice, having heard it many times, and that the
words of distress, spoken so calmly Saturday morning, were those of the
aviatrix, now down in the South Pacific.” “‘Bo’ McKneely, Miss Earhart’s
mechanic at Burbank, CA also heard the call on McMenamy’s powerful set. He
called Paul Mantz, Miss Earhart’s technical adviser, reporting that the radio
call was fast, ‘too fast to distinguish clearly.’ He said after the call
letters something else was sent, ‘probably a position.’” |
Source |
Chicago Herald and
Examiner, Monday, July 5, 1937. |
Probability |
n/a |
Qual Factors |
Pearson’s associate Walter McMenamy later confessed this
was a hoax. (Audio tape in
TIGHAR archives) |
Credibility |
Not credible |
|
80
Identifier |
41437PY |
Z Time/Date |
1437 July 4 |
Local Time/Date |
1437 Z July 4 |
Gardner Time/Date |
0337 July 4 |
Agency/Person |
Pan American Airways radio direction finding station |
Location |
Midway Island |
Freq (kHz) |
3105 |
Content |
A very weak wobbly signal was heard, which sounded like
voice but was too weak to identify. Wake Island also heard this same signal,
but Mokapu did not hear it. |
Source |
Memorandum from Operator in Charge, Midway, to Division
Superintendent. Communications, Alameda dated July 10, 1937. |
Probability |
0.00037 |
Qual Factors |
Earhart’s transmitter was the only plausible source of
voice signals on 3105 kHz in the central Pacific, but also could have been a
west coast aircraft. Itasca did not
transmit to Earhart until 2100Z this day. There is insufficient evidence to decide
if Earhart was the source. |
Credibility |
Uncertain |
|
81
Identifier |
41500RH |
Z Time/Date |
1500-1525 (approx) July 4 |
Local Time/Date |
0800-0825 MST July 4 |
Gardner Time/Date |
0400-0425 (approx) July 4 |
Agency/Person |
Dana Randolph |
Location |
Rock Springs, Wyoming |
Freq (kHz) |
15525 |
Content |
According to the local newspaper, Randolph heard a woman
say “This is Amelia Earhart. Ship is on a reef south of the equator. Station
KH9QQ” at about 0800 MST. The woman then began to give her location, but the
signal faded out before it was given. This sequence was repeated an unknown
number of times during a 25 minute period. |
Source |
“First Radio Contact with Miss Earhart Made by Rock
Springs boy,” Rock Springs Rocket,
July 6-7, 1937, p.1; Finding Amelia,
p. 142; MSG8.PDF, p. 368; and
MSG9.PDF, p. 372. |
Probability |
0.016 |
Qual Factors |
A local Department of Commerce radio operator
investigated and verified Randolph’s report, and found that the call sign
heard was KHAQQ, and that the signal frequency was “near 16000” kHz, which is
close to 15525 kHz, the 5th harmonic of 3105 kHz. It was plausible
for Randolph to be tuning there, since 15525 kHz was near a shortwave
broadcast band. The investigator also found that the signal included a
statement – not reported by the newspaper – that the plane was
“on a reef southeast of Howland Island.” The possibility of a hoax can be
ruled out, given the investigation and the fact that the newspaper was
published every other day, hence printed news of post-loss signals had not
yet reached Rock Springs. |
Credibility |
Credible |
|
82
Identifier |
41500CB |
Z Time/Date |
1500 and unspecified subsequent times, July 4 |
Local Time/Date |
1100 Eastern Daylight Time, July 4 |
Gardner Time/Date |
0400, July 4 |
Agency/Person |
Mrs. Ernest Crabb |
Location |
Toronto, Canada |
Freq (kHz) |
18630 kHz |
Content |
Mrs. Crabb said she heard fragments of a conversation
between a woman and a man she believed to be Amelia Earhart and Fred Noonan,
on her 20-tube radio on Sunday July 4. She said she also heard a few
sentences in what seemed to be Japanese, breaking in. |
Source |
Toronto Daily Star,
July 5, 1937, and Toronto Daily Star,
July 6, 1937. |
Probability |
0.009 |
Qual Factors |
18630 kHz is the 6th harmonic of 3105 kHz. This
reception was simultaneous with the signal on 15,525 kHz, the 5th harmonic of 3105 kHz, heard by Dana Randolph in Rock Springs, Wyoming. There
were two 20-tube home radios with shortwave capability in 1937: the Midwest
Radio Co. Model 20-38, which had a shortwave band covering 10 MHz to 20 MHz,
and the Philco model 37-690X, which had a shortwave band covering 11.5 MHz to
18.2 MHz. There was a 50,000 watt Japanese station – JZL in Tokyo
– at 17,785 kHz. This could explain why Mrs. Crabb was tuning in that
part of the band, and why occasional Japanese sentences could be heard on
18,630 kHz. Home radios of the day had poor selectivity on shortwave bands,
and random changes in the propagation path could allow the JZL signal
strength at Toronto to rise enough to overcome the receiver selectivity and
be heard together with a signal from Earhart’s 50-watt transmitter at Gardner. |
Credibility |
Credible |
|
83
Identifier |
41512PY |
Z Time/Date |
1512 July 4 |
Local Time/Date |
1512 GCT July 4 |
Gardner Time/Date |
0412 July 4 |
Agency/Person |
Pan American Airways Radio direction finding station |
Location |
Midway Island |
Freq (kHz) |
3105 |
Content |
A faint broad signal, apparently voice, was heard but was
far too weak to take a bearing. Wake Island did not hear this signal. Mokapu
reported taking a bearing of approximately 175 degrees true. (Note: The
bearing of Gardner from Mokapu is 213 degrees true.) |
Source |
Memorandum from Operator in Charge, Midway, to Division
Superintendent. Communications, Alameda dated July 10, 1937. |
Probability |
0.00037 (Gardner); less than 1 chance in a quadrillion
for a signal from the west coast. |
Qual Factors |
This signal was heard during the period when voice
signals were heard at Rock Springs and Toronto. Earhart’s transmitter was the
only plausible source of voice signals in the central Pacific. The
possibility of a west coast aircraft source can be ruled out because the
bearing of a west coast source from Mokapu ranged from 038° (Seattle) to 065°
(San Diego). The difference between 213° and the reported bearing of 175° is
plausible given the weak signal and probable skywave directional skewing. |
Credibility |
Credible |
|
84
Identifier |
41523PU |
Z Time/Date |
1523-1530 July 4 |
Local Time/Date |
1523-1530 Z July 4 |
Gardner Time/Date |
0423-0430 July 4 |
Agency/Person |
Pan American Airways Radio direction finding station |
Location |
Mokapu, Oahu |
Freq (kHz) |
3105 |
Content |
Mokapu heard weak carrier signals on 3105 kHz and got a
bearing of 213°, that could be in error by plus or minus 10° due to signal
direction shifting. |
Source |
MSG8.PDF, p. 357. and Memorandum from Pan Am Section
Supervisor, Communications, Honolulu to Division Superintendent,
Communications, Alameda dated July 10, 1937. |
Probability |
0.009 |
Qual Factors |
The signals were heard during the period when credible
Earhart signals were heard at Rock Springs and Toronto. The bearing of Gardner
from Mokapu is 213°. Shifting, or swinging, of a direction finder bearing was
a plausible result of weak-signal multipath interference due to ionospheric
propagation anomalies. |
Credibility |
Credible |
|
85
Identifier |
41553PY |
Z Time/Date |
1553 July 4 |
Local Time/Date |
1553 GCT July 4 |
Gardner Time/Date |
0453 July 4 |
Agency/Person |
Pan American Airways Radio direction finding station |
Location |
Midway Island |
Freq (kHz) |
3105 |
Content |
A weak signal, apparently the same signal heard at 1512Z
was heard but was far too weak to identify. |
Source |
Memorandum from Operator in Charge, Midway, to Division
Superintendent. Communications, Alameda dated July 10, 1937. |
Probability |
0.0066 |
Qual Factors |
The signals were heard shortly after the credible Earhart
signals heard at Rock Springs and Toronto. |
Credibility |
Credible. |
|
86
Identifier |
42100IA |
Z Time/Date |
2100 July 4 |
Local Time/Date |
0930 July 4 |
Gardner Time/Date |
1000 July 4 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Itasca called Earhart in voice, with a long count, requesting
her to respond. |
Source |
RADREST.PDF, p. 162 |
Probability |
n/a |
Qual Factors |
n/a |
Credibility |
n/a |
|
87
Identifier |
42130IA |
Z Time/Date |
2130 July 4 |
Local Time/Date |
1000 July 4 |
Gardner Time/Date |
1030 July 4 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Itasca called Earhart in voice, with a long count, requesting
her to respond. |
Source |
RADREST.PDF, p. 163 |
Probability |
n/a |
Qual Factors |
n/a |
Credibility |
n/a |
|
88
Identifier |
42200IA |
Z Time/Date |
2200 July 4 |
Local Time/Date |
1030 July 4 |
Gardner Time/Date |
1100 July 4 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Itasca called Earhart in voice, with a long count, requesting
her to respond. |
Source |
RADREST.PDF, p. 164 |
Probability |
n/a |
Qual Factors |
n/a |
Credibility |
n/a |
|
89
Identifier |
42230IA |
Z Time/Date |
2230 July 4 |
Local Time/Date |
1100 July 4 |
Gardner Time/Date |
1130 July 4 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Itasca called Earhart in voice, with a long count, requesting
her to respond. |
Source |
RADREST.PDF, p. 164 |
Probability |
n/a |
Qual Factors |
n/a |
Credibility |
n/a |
|
90
Identifier |
42300IA |
Z Time/Date |
2300 July 4 |
Local Time/Date |
1130 July 4 |
Gardner Time/Date |
1200 July 4 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Itasca called Earhart in voice, with a long count, requesting
her to respond. |
Source |
RADREST.PDF, p. 165 |
Probability |
n/a |
Qual Factors |
n/a |
Credibility |
n/a |
|
91
Identifier |
42330IA |
Z Time/Date |
2330 July 4 |
Local Time/Date |
1200 July 4 |
Gardner Time/Date |
1230 July 4 |
Agency/Person |
Itasca |
Location |
Central Pacific |
Freq (kHz) |
3105 |
Content |
Itasca called Earhart in voice, with a long count, requesting
her to respond. |
Source |
RADREST.PDF, p. 165 |
Probability |
n/a |
Qual Factors |
n/a |
Credibility |
n/a |
|
|