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Author Topic: Betty's house  (Read 83065 times)

C.W. Herndon

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Re: Betty's house
« Reply #60 on: July 31, 2012, 11:19:21 AM »

Good post Art. Looks like you have done lots of homework too. :)
Woody (former 3316R)
"the watcher"
 
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Chuck Varney

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Re: Betty's house
« Reply #61 on: July 31, 2012, 03:59:21 PM »


BTW here is Bob Brandenburg's Report on WE-13C Transmitter Harmonic Power Output if you have not seen it yet.

Art, you might also read my comments on the subject paper. (If the significance of the comments are lost on you, let’s just say it’s bad. “Bad” wouldn’t be so bad if the paper’s content weren’t insinuated, in one way or another, into virtually every propagation-related paper by the same author.)

Chuck
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Gary LaPook

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Re: Betty's house
« Reply #62 on: July 31, 2012, 04:01:03 PM »

This string has become one of the most fascinating techno-socio-economic-motive seeking dialogues I have ever seen.  I wish I had more confidence that we could 'prove' Betty could not have heard anything, it would be simpler.

Some may recall that upstring I shared experience from childhood regarding neighbors of modest means who had some very odd things in their home for those of modest means.  Odd things happen in this odd world. 

As I think about it, I'm not sure how to explain how my grandfather - a court recorder in his day - was able to buy my mother a very nice piano before he died in 1935.  They lived in a respectable home and neighborhood, not entirely unlike Betty's.  The depression was on.  As a county (court circuit, actually) employee I doubt he made a lot of salary in Toombs County, GA.


Fascinating.
But remember, court reporters sell copies of their transcripts to the lawyers, that's where the real money is.

gl
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John Balderston

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Re: Betty's house
« Reply #63 on: July 31, 2012, 06:36:19 PM »


BTW here is Bob Brandenburg's Report on WE-13C Transmitter Harmonic Power Output if you have not seen it yet.

Art, you might also read my comments on the subject paper. (If the significance of the comments are lost on you, let’s just say it’s bad. “Bad” wouldn’t be so bad if the paper’s content weren’t insinuated, in one way or another, into virtually every propagation-related paper by the same author.)

Chuck

Chuck, I appreciated your assessment of Mr. Brandenburg's WC-13C harmonic power output analysis - thank you for sharing.  Not being a EE I am taking it on faith that your points on reduced transmitter power as well as reduced harmonic amplitude are correct.  Several follow-on questions for you if I may - 1) are you able to correct Mr. B's model for harmonic attenuation/power ratios?  2)  going back to Woody's question about 500 kc transmission, are you able to offer a calculation of WC-13C 500 kc harmonic amplitude?  And this final question 3) falls into the category of education - I thought a fourier transform was used for calculating rate of change - is this correct?  If so, how does a fourier transform help determine harmonic amplitude?  (If you'd prefer not take the time on this one but can kindly provide a reference I will do my homework).  Thanks very much, John
John Balderston TIGHAR #3451R
 
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don hirth

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Re: Betty's house
« Reply #64 on: July 31, 2012, 06:38:58 PM »

At radiostratosphere.com, some good info. on the Z1000.  A very fine looking and probably
a very highly acheiving radio. Pretty much top of the line. It matters little how her father obtained it.....really. His vacant lot antenna rig was potentially a 'sponge' for the HF signals, heard. As
another member speculated, proximity to nearby power lines 'could' also have enhanced
getting the 'miracle' reception. Many stranger things have happened and the earth's 3 'layers',
troposphere, stratosphere and ionosphere can produce surprising propagation. Let's also NOT forget Dana Randolph from Rock Springs, WY.
dlh
 
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Mark Pearce

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Re: Betty's house
« Reply #65 on: July 31, 2012, 11:14:10 PM »

Here is an interesting article/essay, published in a Tasmanian newspaper and archived on http://trove.nla.gov.au
 
The Examiner (Launceston, Tasmania,] Friday 9 July 1937, page 6.

US. RADIO OPERATORS MAY HAVE BEEN VICTIMS OF FORM OF HALLUCINATION

A feature of the reports of the search for the missing airwoman, Mrs. Amelia Earhart Putnam, which must have interested many readers is the large number of radio stations which claim to have heard signals from the missing aeroplane, so many, in fact, that though some may be authentic, some must almost undoubtedly be either deliberately false reports or else the result of a form of hallucination.
 
There are many thousands of amateur radio operators in the United States, many of them possessing up to-date and highly efficient equipment. The great majority of them are members of a well organized league, and all of them must possess a license from the Department of Commerce, which has power to punish them for spreading false news.
 
The fact, too, that through their league organization they have in the past rendered extremely valuable service at times of national disaster, such as the recent vast floods in the Mississippi, makes it appear extremely unlikely that on this occasion those who have reported hearing messages from Mrs. Putnam have deliberately tried to mislead the public and the search vessels.
 
Auto-Suggestion

A leading medical man in the city yesterday suggested that the real reason for these numerous incorrect reports was a form of mass hysteria or auto-suggestion, which may give rise to extraordinary hallucinations. It might even be, he suggested, a case of what psychologists call "wish fulfillment." So anxious were the operators to hear the signals from the plane that their sub-conscious minds affected their conscious minds to such an extent that they actually believed they heard the messages they were waiting for.

A leading text-book describes the effects of auto-suggestion as follows: -"In states of ecstasy or intense concentration of the attention upon some one ideal object, the object contemplated seems at times to take on sensory vividness, and so to acquire the character of an hallucination. In these cases the state of mind of the subject is probably similar in many respects to that of the deeply hypnotised subject, and these two classes of hallucination may be regarded as very closely allied."

Craving for Notoriety

Besides this possibility of unconscious deception, there is also the possibility that some of the operators had something in common with that numerous [???] of persons who, whenever a spectacular murder is committed, immediately begin pestering the police with confessions of the crime, despite the fact that they may have been many miles from where it occurred or were physically incapable of committing it.
 
These people deceive themselves into the belief that they have committed the crime because of a sub-conscious craving for notoriety, and in just the same way some of these radio operators may have deceived themselves into the belief that they heard signals from Mrs. Putnam, because of their desire for the publicity and local fame they would thus gain.
« Last Edit: September 20, 2012, 08:27:11 PM by Mark Pearce »
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pilotart

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Re: Betty's house
« Reply #66 on: August 01, 2012, 09:30:38 AM »

<...>some of these radio operators may have deceived themselves into the belief that they heard signals from Mrs. Putnam, because of their desire for the publicity and local fame they would thus gain.
Some Reports were from 'Professional' Radio Operators (like the British Warship Achellies {?SP}), Naru {sp} Radio and PanAm HF/DF Stations, their reports carry the most value. 

At least some amateurs (like the pair in California who ended up as front-page photo news) did report fabricated calls and they should have lost more than just their License for that cruel and harmful report...

The non Professional/Amateur Operators like Dana, Betty and some of the others like the ladies from Texas and Maine just add to the mix. 

Betty especially, due to her keeping a contemporaneous Log of the event.

TIGHAR posted a research paper on post-loss radio messages and determined that many WERE not credible.
Art Johnson
 
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pilotart

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Re: Betty's house
« Reply #67 on: August 01, 2012, 10:57:07 AM »

At least one of those 'Ladies' later (much) reported that they had copied Lat/Lon and possibly other valuable information.
Quote
The non Professional/Amateur Operators like Dana, Betty and some of the others like the ladies from Texas and Maine just add to the mix. 
This information was never published "...because (she said) President Roosevelt had requested not to divulge such information as it might be harmful to the castaways..."   What a Missed opportunity.

I do know that it would have generated countless fabrications, but if there had been an immediate 'call-out' to report ANY Radio Message copied that might have come from the lost aviators, how different the outcome might have been...

There would have had to have been considerable 'vetting'  of reports, but that could have been done.

If Only They Had Accepted that British Warship's offer of Assistance!  She could likely have had her Float Planes launched and over-flying the Phoenix Islands in time for a successful rescue.  :(
Art Johnson
 
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Chuck Varney

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Re: Betty's house
« Reply #68 on: August 01, 2012, 12:05:31 PM »

Not being a EE I am taking it on faith that your points on reduced transmitter power as well as reduced harmonic amplitude are correct. Several follow-on questions for you if I may -
1) are you able to correct Mr. B's model for harmonic attenuation/power ratios?

If you’re asking whether I’ve done what I suggested that Bob do, and whether I have found what I suggested that he might find, the answer is yes.

Quote
2)  going back to Woody's question about 500 kc transmission, are you able to offer a calculation of WC-13C 500 kc harmonic amplitude?

I can’t tell what the two of you are really asking, or why. If you want to elaborate, start with the why.

Quote
And this final question 3) falls into the category of education - I thought a fourier transform was used for calculating rate of change - is this correct?

No. A Fourier transform is used to decompose a time-dependent signal into an equivalent set of sinusoids; that is, to transform the signal’s representation from one that’s a function of time to one that’s a function of frequency.

Quote
. . .how does a fourier transform help determine harmonic amplitude?  (If you'd prefer not take the time on this one but can kindly provide a reference I will do my homework).

I used The Scientist and Engineers Guide To Digital Signal Processing as a reference. The opening words in Chapters 8-11, may give you a feel. 

Chuck
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C.W. Herndon

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Re: Betty's house
« Reply #69 on: August 01, 2012, 12:28:58 PM »


I can’t tell what the two of you are really asking, or why. If you want to elaborate, start with the why.

Chuck

The why is, I have not seen this addressed.

The question is, if AE broadcast some of her calls for help on 500 kHz would it be possible that Betty, and/or others in the U.S., could have heard it?
Woody (former 3316R)
"the watcher"
 
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Chuck Varney

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Re: Betty's house
« Reply #70 on: August 01, 2012, 07:17:16 PM »

The why is, I have not seen this addressed.

The question is, if AE broadcast some of her calls for help on 500 kHz would it be possible that Betty, and/or others in the U.S., could have heard it?

Assume that the 500 kHz plus CW modification made to AE’s transmitting equipment was like that later incorporated with the model 13CB transmitter. Transmitting on the 13CB’s 325 to 500 kHz band used a trailing wire antenna in conjunction with a loading coil external to the transmitter chassis. Remove them, as was  done on AE’s Electra, and you lose the means to radiate power in that band. A signal not radiated is a signal not received.

Chuck
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John Balderston

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Re: Betty's house
« Reply #71 on: August 01, 2012, 10:14:12 PM »


Quote
And this final question 3) falls into the category of education - I thought a fourier transform was used for calculating rate of change - is this correct?

No. A Fourier transform is used to decompose a time-dependent signal into an equivalent set of sinusoids; that is, to transform the signal’s representation from one that’s a function of time to one that’s a function of frequency.

Quote
. . .how does a fourier transform help determine harmonic amplitude?  (If you'd prefer not take the time on this one but can kindly provide a reference I will do my homework).

I used The Scientist and Engineers Guide To Digital Signal Processing as a reference. The opening words in Chapters 8-11, may give you a feel. 

Chuck

Chuck, thanks very much for your response and education on Fourier transform - sincerely appreciated.  I did your recommended reading in Ch. 8 - 11 on discrete Fourier transform.  I now have a feel for why you recommended to Mr. B. analyzing a single waveform using a discrete Fourier Transform as the analysis tool.   Thanks for that!  On a related note, I stopped by the company research library at lunch today and was able to lay my hands on a copy of "Radio Engineering Handbook", Keith Henney (ed.), 1935.   Seeking a better grasp of the tools a practitioner like Gurr would have used for problem solving.
John Balderston TIGHAR #3451R
 
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John Balderston

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Re: Betty's house
« Reply #72 on: August 01, 2012, 10:53:02 PM »

The why is, I have not seen this addressed.

The question is, if AE broadcast some of her calls for help on 500 kHz would it be possible that Betty, and/or others in the U.S., could have heard it?

Assume that the 500 kHz plus CW modification made to AE’s transmitting equipment was like that later incorporated with the model 13CB transmitter. Transmitting on the 13CB’s 325 to 500 kHz band used a trailing wire antenna in conjunction with a loading coil external to the transmitter chassis. Remove them, as was  done on AE’s Electra, and you lose the means to radiate power in that band. A signal not radiated is a signal not received.

Chuck

Chuck, understand your significant point that a "signal not radiated is a signal not received."  However, really seeking your expertise here.  The "why" of the 500 kc transmission question is the six pages of electro-socio-economic debate  :) about whether Betty could have actually heard a post-loss transmission, the assumption being that the reception would have been a 4th harmonic of 6210 kc.  And at that, as you point out, Mr. B's transmission model was extremely optimistic.  Because receiving the 8th harmonic of 3105 kc is even more unlikely, it's worthwhile to analyze the probability that Betty (and Dana Randolph) received a 500 kc transmission, however remote.

Mike Everett's NR16020 radio analysis (and the primary source Gurr/Goerner interview) indicate Gurr integrated a home-made loading coil into the -13C for 500kc operation.  If you have a working transmitter/antenna/atmosphere model, would you please consider estimating Gurr's 500 kc loading coil "power ratio" (for lack of a better term) and analyze the probability of reception?  Yes, we can assume it would be worse than harmonics of 6210 or 3105 kcs, but are we sure?  Sincerely, John
John Balderston TIGHAR #3451R
 
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Chuck Varney

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Re: Betty's house
« Reply #73 on: August 02, 2012, 01:12:56 PM »

. . .Because receiving the 8th harmonic of 3105 kc is even more unlikely, it's worthwhile to analyze the probability that Betty (and Dana Randolph) received a 500 kc transmission, however remote.

John,

Worthwhile?

If you sense some reluctance on my part to pursue what I view to be a pointless exercise, then you’re right. I’ve seen no claim that AE had the capability to radiate a signal at 500 kHz when she departed on her second world flight, nor have I seen a claim that anybody heard a transmission from her on that frequency, or a harmonic of that frequency. Have you?

Quote
Mike Everett's NR16020 radio analysis (and the primary source Gurr/Goerner interview) indicate Gurr integrated a home-made loading coil into the -13C for 500kc operation.  If you have a working transmitter/antenna/atmosphere model, would you please consider estimating Gurr's 500 kc loading coil "power ratio" (for lack of a better term) and analyze the probability of reception?  Yes, we can assume it would be worse than harmonics of 6210 or 3105 kcs, but are we sure?

Here’s a flavor of the problem Gurr faced if he tried to make do with the dorsal V antenna on 500 kHz. Under the conditions I used for estimating behavior at 3.105 and 6.21 MHz, the antenna at 500 kHz has a feedpoint impedance of 0.23 – j 3960 ohms and a radiation efficiency of 5.8%.  (For comparison, I had 1.42 – j 476 ohms at 65% efficiency for 3.105 MHz, and 4.94 – j 27 ohms at 76% efficiency for 6.21 MHz.).

I introduced a loading coil in series with the antenna to get the net reactance closer to the value I had at 3.105 MHz. The last coil design I tried reduced the reactance by 3314 ohms, but introduced more than 4 ohms of additional loss. So the combined loading coil and antenna impedance was 4.3 - j 646 ohms, but had a radiation resistance of 5.8% of 0.23 ohms, or 0.013 ohms. That makes the radiation efficiency of the combined antenna and loading coil equal to 0.3%. If 1 watt is delivered to the combination, only 3 milliwatts is radiated. A new tuning coil design will be required, and it will introduce yet more loss, delivering even less power to the combination.
 
Hopefully you can see that significant effort is required to get an an output power number, and more work is required for each harmonic you want to explore.

I don’t have a propagation prediction program for medium frequencies. If one were to use an HF prediction program you’d need to be at the 5th harmonic of 500 kHz at a minimum, and preferably at the 6th harmonic. Don’t expect much. For example, at 3.105 MHz with a plate output power of 53 watts, the radiated power was 22 watts. The radiated power at the 5th harmonic was 6 microwatts.

Chuck
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Chuck Varney

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Re: Betty's house
« Reply #74 on: August 02, 2012, 01:27:33 PM »

Was the 'loading coil' also known to have been removed when they removed the trailing wire?

Jeff,

Well, "known" is a slippery word when applied to equipment aboard the Electra, but with AE's demonstrated penchant for weight saving I'd think that it went when the trailing wire antenna did.

Chuck 
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