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 21 
 on: August 05, 2018, 04:48:17 PM 
Started by Ric Gillespie - Last post by Ric Gillespie
Well put Jenn.

 22 
 on: August 05, 2018, 04:46:54 PM 
Started by Ric Gillespie - Last post by Ric Gillespie
Bob Brandenburg, referring to the Philco service guide for the model 38-9, says:

"The receiver had 2 tuning bands:
(1) 530 kHz to 1720 kHz  (standard broadcast)

(2) 5.7 MHz to 18.2 Mhz (shortwave)

The schematic shows there was no RF amplifier stage.  The input signal went directly to the mixer stage where the signal frequency was converted to the internal intermediate frequency (IF) of 470 Khz.  The mixer input circuit was tuned, but the absence of a tuned RF amplifier preceding the mixer means the receiver selectivity likely was less than optimum.

The schematic also shows connection points for connection to an antenna.  That could have been an antenna mounted in the radio cabinet, or an external antenna.  It's unknown what kind of antenna Paxton had.

The upper limit of the designed frequency range, 18.2 MHz, was well below the 18.64MHz 4th harmonic of AE's day frequency.  However, the RF selectivity could have been broad enough to allow a 4th harmonic signal to be received at the top end of the tuning dial."


But, of course, Paxton said on more than one occasion that she heard Earhart on the "band between 12 and 13 mHz".

 23 
 on: August 05, 2018, 02:23:01 PM 
Started by Ric Gillespie - Last post by Jennifer Hubbard
This is the quote that struck me most strongly:

"In a report written after the search for Earhart had failed, the commanding officer of the Coast Guard cutter Itasca categorically dismissed all of the reported post-loss signals."

We can see how things developed to keep AE and FN's fate so shrouded in mystery and doubt. By the time the islands were searched (flown over), Earhart's plane was not visible to the searchers. Therefore, they concluded she had not landed there. Therefore, if she had not landed, she must have crashed and sunk. Therefore, if she had crashed and sunk, the signals could not have been legitimate. It's a chain of logic resting on that first link of not finding the plane. If not for that first faulty link, these transmissions would have been taken more seriously long ago. The article lays out very well how the transmissions fit into all the other evidence, and why there is a problem with that first link in the chain.

 24 
 on: August 05, 2018, 12:33:20 PM 
Started by Ric Gillespie - Last post by Greg Daspit
Describing how far they were from Lae and listing distances  and generic directions of islands really far away does not seem like a good way to describe where you are.  It does seem like chatter she may have heard other operators using to describe the area of Pacific they were in. She may have really thought she heard her, not paying real attention, and then tried to make sense of it after the fact.

edit: I think the one in one quadrillion chance is the nail in the coffin.

 25 
 on: August 05, 2018, 12:16:37 PM 
Started by Ric Gillespie - Last post by Joe Cerniglia
Even if she did defy the odds and hear AE one time
I have to say this is fascinating. Some thoughts:
The official odds that Mrs. Paxton heard Earhart on anything lower than 24840 kHz, as cited in the radio message catalogue, are one in one quadrillion. With all due respect (and respect is due, IMHO), it's really hard for me to see that as just defying the odds. That's more like defying the laws of space, time, gravity, and whatever else remains of physics all at the same time. (I take the number literally, as a mathematically derived probability, as I think I was intended to.)

One quadrillion is a number so huge as to beggar human comprehension. It's the number of stars in about 10% of the entire universe that we can see with the best telescopes. For all practical purposes, the odds were zero.

Yet Nina Paxton wrote to Time Magazine on July 14, 1937 that she was listening on the "band between 12 and 13 mHz" (2nd harmonic of AE's day frequency was 12.42 mHz) and heard Earhart with a reception that was "anything but weak."

Ms. Paxton's official status concerning her report is "not credible." Maybe she heard something that just wasn't there (and got lucky in naming the right harmonic). Maybe she was a hoaxer. We can agree she embellished, invented, over-interpreted, misremembered, and altered her story over time. But Matt, if she "did defy the odds and hear AE one time" her status, in my opinion, is probably closer to "uncertain." And if, however she reported it afterward, if whom she heard was AE that one time, it means that the radio propagation to frequency probabilities might warrant a second look. But those are the possibilities, as I see them. I'm absolutely willing to entertain more if I'm missing some.

Other than that, I agree with everything you've said. (I think identifying the Philco in the photograph was most impressive, btw.)

Joe Cerniglia
TIGHAR #3078R


 26 
 on: August 05, 2018, 11:19:50 AM 
Started by Ric Gillespie - Last post by Greg Daspit
Based on the same operator (Coast Guard Hawai'i) hearing dashes on frequency 6210 (Number 27) just after hearing dashes on frequency 3105 (Message 26), shouldn't number 27 be listed as "Primary or Second Harmonic".

Number 27 is the only one that lists the frequency as 6210, without the possibility of it also being a second harmonic.

I'm wondering if 6210 worked at all after the plane landed.

 27 
 on: August 05, 2018, 10:53:54 AM 
Started by Ric Gillespie - Last post by Ric Gillespie
Ric,
Of the island.
Ted

The long axis of the island (from main lagoon passage to SE tip) runs 317°/137° True

 28 
 on: August 05, 2018, 10:40:36 AM 
Started by Ric Gillespie - Last post by Ted G Campbell
Ric,
Of the island.
Ted

 29 
 on: August 05, 2018, 08:27:27 AM 
Started by Ric Gillespie - Last post by Ric Gillespie
I know the credible messages were over by July 9, were there other reports after that or was Paxton the only one to claim to be still hearing them?

The last technically-credible message was number Message 170 received by Howland Island on the night of July 8.  There were seven reported receptions after that (not counting Paxton's), five of which were by private citizens.  They are listed in the 2011 Post-Loss Radio Catalog and Analysis

 30 
 on: August 05, 2018, 08:16:11 AM 
Started by Ric Gillespie - Last post by Matt Revington



Quote from: Joe Cerniglia link=topic=2017.msg42507#msg42507
.

Bob Brandenburg has stated in his radio analysis that Nina Paxton's odds of hearing Earhart were "0.003 on 24,840 kHz, the 4th harmonic of Earhart’s daytime frequency (6210 kHz); less than one chance in a quadrillion on any lower frequency."

If Nina Paxton was using an unmodified Philco 38-9K in 1937, and if Bob Brandenburg's analysis of radio propagation and receiving odds by tuning frequency is accurate, Nina Paxton is unlikely to have heard Earhart in 1937.

Joe Cerniglia
TIGHAR #3078R
In his post Les McKinney quotes Paxton as saying she was listening at 12 mega cycles.

“Since hearing her so well on Saturday, July 3, I have heard a few sentences at times that could have been KHAQQ unless they were KHAQQ," and in a letter to Congressman Vinson on August 12th said, "Sunday August 8, at 10:15 p.m., I heard the word "Earhart" and a few sentences which I could not understand other than the sound "matoe" on 12 megacycles."

Even if she did defy the odds and hear AE one time it really stretches credibility that she would be  picking up further messages on several further occasions well into August.

I know the credible messages were over by July 9, were there other reports after that or was Paxton the only one to claim to be still hearing them?

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