TIGHAR

Amelia Earhart Search Forum => Radio Reflections => Topic started by: JNev on March 22, 2011, 12:26:21 PM

Title: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: JNev on March 22, 2011, 12:26:21 PM
If this belongs in Radio Reflections or somewhere else, my apologies - please feel free to move it, Marty or whomever.

So moved.

Mulling over how AE and FN may have gotten to Gardner when they did not find Howland I landed on the  Cooper Report in Research Document #38  (http://tighar.org/Projects/Earhart/Archives/Documents/Cooper_Report/Cooper_Report.pdf) - a fascinating and lucid accounting by a contemporary witness of apparently excellent character and skill.  I'm probably re-capping something already covered here somewhere, and if so, my apologies.

Looks like the 3105 Donut got replaced by the 350 NM cone of silence after 043 that fateful day. 

Thoughts, anyone?
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Martin X. Moleski, SJ on March 22, 2011, 01:10:00 PM
That said, if the  The 3105 Donut (Tracks Vol. 24, Oct. 2008)  (http://tighar.org/Publications/TTracks/2008Vol_24/1008.pdf) is true, and I believe it is a rational explanation of how AE's tranmitter was behaving, why didn't AE continue to transmit - and Itasca receive - as she finally tracked to the southeast toward Gardner?

You don't seem to be paying attention to the full contents of the last transmission: (http://tighar.org/wiki/Last_transmission) "Will repeat this on 6210" suggests that AE was switching to her daytime frequency. (http://tighar.org/wiki/Frequency#Daytime.2Fnighttime_frequencies)  The maxim she was following was, "The higher the sun, the higher the frequency."  She did not hear anything from the Itasca on 3105, so she did not hear them asking her not to change frequency.  If she did switch frequencies as she announced she was going to do, then all 3105 donut considerations go out the window from then on.  You then have to deal with the vagaries of her daytime frequency.

She was not heard on that frequency until 0418 GMT (http://tighar.org/wiki/Transmission_timeline)--four hours and eighteen minutes after 0000 GMT, her takeoff time from Lae.  That suggests to me that there was something odd about her daytime setup.  Whatever it was that kept Lae from hearing her for four hours may also have kept the Itasca from hearing her at all.  She might have reached Niku two or three hours after the last transmission.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Steve D. Burk on April 01, 2012, 04:22:07 PM
I tend to agree with much of Jeff's original post on this topic.  Given that AE was low on fuel and lost, had only two voice transmission frequencies available to her (3105 and 6210), and her final transmission was judged by those who heard it to sound "frantic", it strikes me as highly unlikely that she would doggedly stick to transmitting only on her daytime frequency of 6210.  Her transmissions received by Itasca had gotten progressively stronger over several hours, reaching strength 5 in her final transmission.  And then absolutely zip.  She had only said she would repeat her final message on 6210.  Did she then fly for several hours afterward without anyone hearing from her ---and with her only attempting to contact Itasca on a single frequency despite their desperate state?  Seems highly unlikely to me.  What am I missing?
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Brad Beeching on April 01, 2012, 08:23:27 PM
It is only speculation on my part, but the only answer that makes any sense to me and the only answer to the question of "Why did Amelia quit transmitting?" has to be is.. she didn't. I cannot believe she would have quit trying to contact Itasca or Howland or anyone else who could hear her. I think the problem was that no one heard her. Is that due to them listening on the wrong time schedule? Listening on the wrong frequency at the wrong time schedule? I do not know, But in the post loss receptions, some who heard her transmissions reported only a carrier wave or just a hum or garbled voice. Perhaps she had a problem with the transmitter as well as the problems associated with the loss of the recieving antenna?

Brad
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Steve D. Burk on April 02, 2012, 09:02:39 AM
The two major possibilities seem to be: (1) after her final transmission on 3105, AE switched to 6210 and, for whatever reason, there was a problem with 6210 and it was never received by Itasca or those in the vicinity.  In this scenario AE flies on for several more hours and never transmits again on 3105 while in the air; or (2) after her final transmission on 3105 the Electra ran out of gas and the "crash and sink" scenario occurs very quickly since she was flying at 1000 ft.  Given the circumstances, I find scenario (1) highly improbable.  That is, AE could not afford to simply casually continue transmitting at regular, rather widely spaced intervals on a single frequency as if it was business as usual.  The Itasca and others knew the situation was dire and they were listening intently on 3105 and 6210 (not just listening at predetermined intervals of time), but her transmission went abruptly from signal level 5 to nothing on any frequency.  One can forcefully argue that she couldn't possibly have run out of gas (although AE herself said she was low on fuel and sounded absolutely frantic in her final transmission), but that assertion has its own set of requirements and unknowns (she definitely started with 1100 gal; she didn't encounter strong headwinds, etc.).  As much as I find the post-flight research fascinating ---at this point in my understanding, I am unable to get over the hurdles outlined above.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Jeff Victor Hayden on April 02, 2012, 10:53:37 AM
It would appear that the communications problems which dogged the approach to and, failed location of Howland continued on until, well we don't know , landing, ditching? Does that sound plausible? Sounds plausible, neither AE or Itasca could get the other to do what they requested regarding frequencies in a consistent and reliable manner. Perhaps she was transmitting, on the wrong frequency and, maybe Itasca was listening, on the wrong frequency?
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Steve D. Burk on April 02, 2012, 11:21:56 AM
She could only transmit by voice on two frequencies (3105 and 6210) and the Itasca and others were monitoring both of these.  As she approached Howland the strength of her transmissions on 3105 as recorded by Itasca grew progressively from level 1 to 5 over a several hour period, then abruptly they never heard further from her in the air again on either 3105 or 6210.  Her transmission went from almost overloading the Itasca speaker to zip---no fading back from signal level 5 to lower values.  True, two-way voice communication was never established.  Although Itasca heard her signal progressively increase in strength as she approached, they never heard it progressively decrease as she, presumably according to the TIGHAR scenario, flew SE for several hours.  Is that because she switched to 6210 and never used 3105 again (and there was some unknown problem with 6210)?  With only two choices of frequencies, lost, low on fuel, and desperate it seems unlikely to me that she bet everything on her "daytime" frequency of 6210 and never tried 3105 again.  At least that is my take.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Jeff Victor Hayden on April 02, 2012, 12:24:32 PM
Good points and well put Steve. Another scenario would be that after getting nowhere with comms on 3105 and 6210 she may have concluded that Itasca couldn't hear her (wrongly) so didn't bother wasting any more time/effort and simply concentrated on getting the airplane on Terra Firma. Given the fuel situation establishing comms could wait until they were safely on the ground. On the other hand they may have just ridden it into the ocean.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Steve D. Burk on April 02, 2012, 01:38:13 PM
Jeff: Actually AE did acknowledge hearing signals from Itasca only 45 min. before her final transmission!  Here is a quote from p.97 of the hardback version of Ric Gillespie's "Finding Amelia":
"Although he could not send the long count Earhart requested, Galten immediately responded with a series of As on 7500 kilocycles and, at 8:00 am, was rewarded with a direct response from Earhart on 3105:"KHAQQ calling Itasca.  We received your signals but unable to get a minimum. Please take a bearing on us and answer 3105 with voice."  This was both good news and bad news.  For the first time Earhart had heard Itasca's signals, but she had not been able to take a bearing using her own direction finder."

Given that AE had heard Itasca's signals just 45 min. before her final (in-air) transmission, and considering her desperate plight, doesn't it seem a very strange time to totally abandon all attempts to make radio contact and fly off into the wild blue yonder for several more hours?
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Gary LaPook on April 02, 2012, 08:18:56 PM
Good points and well put Steve. Another scenario would be that after getting nowhere with comms on 3105 and 6210 she may have concluded that Itasca couldn't hear her (wrongly) so didn't bother wasting any more time/effort and simply concentrated on getting the airplane on Terra Firma. Given the fuel situation establishing comms could wait until they were safely on the ground. On the other hand they may have just ridden it into the ocean.
Gee, that would be tough, having to push the button on the microphone while looking out the window while the autopilot holds that magic 157° heading. Golly, I don't see how any pilot would have been able to do that. After all, it's not like her life might depend on establishing communications with the Itasca.

Wait a second, let me think about that some more. Right, now I remember at least one occasion where I was talking into the microphone while looking out the window for other traffic, Oh! and hand flying the plane at the same time.

gl
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Jeff Victor Hayden on April 03, 2012, 03:51:50 AM
No, I think you missed the point I was trying to make there Gary.
1. When low on fuel (gas?)would it not be wise to put it down somewhere as a priority?
2. Having trouble comminicating with Itasca was a distraction, many aircrashes are attributed to crew being distracted with some problem or another, meanwhile no one is actually flying the plane. I recall Eastern Airlines flight 401 where the whole crew concentrated their efforts on a 'faulty' landing gear light while the plane flew itself into the ground.
3. I'm sure it's easy to press a switch, look out of the windows and fly the plane at the same time  :), in normal circumstances ;)
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: John Ousterhout on April 03, 2012, 08:10:57 AM
Changing transmission frequencies was pretty easy in the Lockheed - not much more than turning a 3-position switch.  However, changing the receiving frequency was more involved, requiring some "head-down" work to pick the band (she had just been listening on 7500 on the DR loop, then presumably changed to 6210), then dial in the frequency while reading the numbers on the dial, then possibly fine-tuning to get the best reception.  Sometime in there she also switched antennas, from the directional loop to the (possibly missing) belly antenna.
 She may have been preoccupied dialing in the receiver, trying to pick up Itasca, although I find it hard to believe she wouldn't continue to transmit "blind".  It seems that she didn't realize that she could receive ok on the loop, but not on the belly antenna.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Martin X. Moleski, SJ on April 03, 2012, 08:41:53 AM
It seems that she didn't realize that she could receive ok on the loop, but not on the belly antenna.

This, for me, is the most important mistake that AE and FN made with their radio equipment.

It seems to me that if she had simply tuned from 7500 kcs to 3105 kcs after hearing the letter A on her DF antenna, she ought to have been able to hear the Itasca's voice transmissions.  She and Fred seem not to have thought of trying a different frequency after 7500 kcs failed to give them a null.  It's very sad in hindsight.  I'm sure their decisions made sense to them at the time they made them.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Steve D. Burk on April 03, 2012, 08:51:40 AM
But please reread my quote above of AE's transmission.  She says: "We received your signals but unable to get a minimum. Please take a bearing on us and answer 3105 with voice."  Clearly she was going to listen on 3105 after receiving the As.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Steve D. Burk on April 03, 2012, 09:06:13 AM
Sorry --realized my mistake above immediately after posting.  AE no doubt switched back to the missing belly antenna and set the receiver to 3105 rather than using the loop antenna to receive 3105.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Martin X. Moleski, SJ on April 03, 2012, 11:40:37 AM
But please reread my quote above of AE's transmission.  She says: "We received your signals but unable to get a minimum. Please take a bearing on us and answer 3105 with voice."  Clearly she was going to listen on 3105 after receiving the As.

But she apparently reconfigured her receiving system so that she did not hear the answer on 3105.

My suggestion is that she leave it set for Direction Finding (whatever that meant in terms of switches and knobs) and only change the frequency.

Her DF was designed to work with low frequencies (http://tighar.org/wiki/Failure_to_communicate#Apparent_ignorance_of_the_limitations_of_her_equipment).  There was no reason for her to try direction finding solely on 7500 kcs.  In fact, as far as we can tell, she had no rational reason to expect her equipment to work on that frequency at all.  But if she had tried doing DF on that frequency, she probably would have heard voices talking to her, which then should have led to getting everything straightened out in getting her DF system or the Itasca's to provide a bearing to Howland.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Steve D. Burk on April 03, 2012, 12:08:06 PM
Yes, Marty, I think we are in agreement now.  See my correction above.  This is, however, "drifting" (AE's term?) away from my primary concern as to what the most likely explanation is for not hearing from AE after 8:45 am that morning.  Could Itasca and others only hear her on 3105 and she switched to 6210, never to return to 3105 again while in flight?  Is that a superior explanation to the "crash and sink" scenario?  This is where I am currently stuck. 
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Steve D. Burk on April 03, 2012, 03:49:25 PM
Thank you very much, Jeff, for that thorough and thoughtful answer.  As a newbie I wanted to be sure that I understood the basics of the various hypotheses.  Personally I find it very difficult to accept that given the dire circumstances and the ease of switching from 6210 to 3105 that AE would only transmit on 6210 for the last several hours.  On top of that, if she was using 6210 ---and only 6210---for several hours, why wasn't she heard?  And finally, the idea that she may have totally given up trying to transmit ---after she had heard the As signal from the Itasca and reported hearing them ---seems the most far-fetched of all options.  She could easily have handled transmitting as she flew SE towards Gardner I., just as she had done as she approached Howland (varying from signal level 1 to 5 in the process).  The "crash and sink" option is abhorrent to me, but encompasses much of what occurred in a manner that doesn't strain credulity ---at least for me.  It appears on these pages there are some very technical disagreements about what distance 1100 gal (if she really even started with that amount) can produce for this Electra.  So, at this point we disagree, Jeff.  However, I find the TIGHAR research to be fascinating and surely hope the upcoming Search is a success!
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Martin X. Moleski, SJ on April 03, 2012, 05:16:20 PM
Personally I find it very difficult to accept that given the dire circumstances and the ease of switching from 6210 to 3105 that AE would only transmit on 6210 for the last several hours.

I don't find it difficult.  It was daytime.  She thought it was time to use her daytime frequency (http://tighar.org/wiki/Frequency#Daytime.2Fnighttime_frequencies). 

Quote
On top of that, if she was using 6210 ---and only 6210---for several hours, why wasn't she heard?

Perhaps for the same reason (whatever it may have been) that she wasn't heard on 6210 until four+ hours after takeoff from Lae. (http://tighar.org/wiki/Transmission_timeline)  We are accustomed to extremely reliable radio equipment.  The folks in 1937 were not.  Notice that the Itasca did not want her to change her frequency (http://tighar.org/Projects/Earhart/Archives/Research/Bulletins/37_ItascaLogs/pos2page3.html)--I suggest that they knew from experience how hard it might be to pick up the higher frequency: "KHAQQ from ITASCA. Transmitting information on answering frequencies. We can hear you fine on 3105. Please go ahead on 3105. Sent on 7500. Unanswered. 8:42-8:46."

Note, too, that they transmitted this on 7500 kcs, which means that they had to use Morse Code, which means that they did not understand that Earhart and Newman could not understand Morse Code, which is just one more component of the failure to communicate (http://tighar.org/wiki/Failure_to_communicate).
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Steve D. Burk on April 03, 2012, 07:23:47 PM
At 7:58 am AE requested (on 3105) a long count from Itasca.  Itasca immediately responded (as best they could) on 7500 with a series of Morse code As.  Two minutes later AE acknowledged (on 3105) hearing the Itasca signals.  From that exchange, she certainly would have concluded that Itasca had been able to hear her on 3105 even though she could not hear them via voice.  That fact is the type of potentially life-or-death noteworthy bit of information that would not be lost on AE.  But instead we are to believe that she subsequently switched to 6210 because it was her "daytime" frequency ---flew several hours using only 6210 while getting no response whatsoever from Itasca--- and never used 3105 again despite having had success in contacting Itasca at 8 am on 3105---while the sun was up.  I guess it is possible, but ....there is another explanation for this pilot thatwas, according to her, "low on fuel" and lost ...
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Gary LaPook on April 03, 2012, 09:56:44 PM


Perhaps for the same reason (whatever it may have been) that she wasn't heard on 6210 until four+ hours after takeoff from Lae. (http://tighar.org/wiki/Transmission_timeline) 

But Chater explained that the reason that they could not hear the plane on 6210 for several hours after takeoff was due to "local interference" so no reason to think there was something weird with the propagation of the frequency and there should not have been any "local interference" at Howland so there is no reasonable explaination as to why she would not have been heard on that frequency IF she had completed switching the transmitter. This, coupled with her prior statement of "1/2 hour of gas left," supports Long's theory that she lost the engines at that time (remember both engines were fed from the same tank so both would flame out within seconds of each other) and was too busy attempting the ditching to talk on the radio as had been suggested.

If, instead, she flew for almost three more hours to Gardner then it is beyond credulity that she would not have had the time, the ability and the imperative to transmit "in the blind" on each of her frequencies informing Itasca and the whole world  of her intentions.

gl
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Gary LaPook on April 03, 2012, 10:12:02 PM
No, I think you missed the point I was trying to make there Gary.
1. When low on fuel (gas?)would it not be wise to put it down somewhere as a priority?
O.K. so she was attempting to ditch just moments after her last transmission at 2013 Z so didn't have the time to talk on the radio, I'll buy that. And yes, you want to ditch or land prior to the engines going quiet since this gives you the ability to adjust your touchdown as necessary based on what you are seeing in the last few seconds. Once you run that last drop of fuel through the carbs you are stuck with crashing into whatever is in front of you. We call this a "precautionary landing." I remember one dark night landing in a corn field with engine problems and I had the ability to jump over some power lines I saw at the last second and land safely beyond them. If I had waited for the engine to quit completely then I would have hit the lines and I would not be typing this now.
Quote
2. Having trouble comminicating with Itasca was a distraction, many aircrashes are attributed to crew being distracted with some problem or another, meanwhile no one is actually flying the plane. I recall Eastern Airlines flight 401 where the whole crew concentrated their efforts on a 'faulty' landing gear light while the plane flew itself into the ground.
The EA 401 event lasted only 8 minutes from start to finish, not the three hours necessary to fly to Gardner. Also, the crew of EA 401 made a number of radio transmissions during that period.
Quote
3. I'm sure it's easy to press a switch, look out of the windows and fly the plane at the same time  :), in normal circumstances ;)
It's pretty easy in abnormal circumstances too, I've done it lots of times.

gl
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Martin X. Moleski, SJ on April 04, 2012, 06:20:45 AM
But Chater explained that the reason that they could not hear the plane on 6210 for several hours after takeoff was due to "local interference" ...

Chater gave an explanation that made sense to him.

I find it hard to imagine that "local interference" overrode the eight scheduled transmission times that were not heard.

I understand that this is speculative.

Quote
If, instead, she flew for almost three more hours to Gardner then it is beyond credulity that she would not have had the time, the ability and the imperative to transmit "in the blind" on each of her frequencies informing Itasca and the whole world  of her intentions.

It's not beyond my credulity.  AE did lots of things that are, in retrospect, incredible.  It strains my credulity that she would fail to master the radio system on which her life depended, and yet, that seems to have been the choice she made (http://tighar.org/wiki/Failure_to_communicate#Misunderstanding_of_equipment:_Amelia_Earhart).  When push came to shove, she did not know how to transmit a signal on the right frequency for the right length of time for the Itasca to get a bearing, nor did she know what was the best frequency for her to use to take a bearing on.  She didn't switch between 3105 and 6210 during the morning hours; in my imaginative reconstruction of what she "would have done," she didn't switch between 3105 and 6210 after announcing her plan to go to her daytime frequency.

I've got to add the failed RDF test in Lae (http://tighar.org/wiki/Delayed_in_Lae#Failed_direction_finding_test) to my list of indicators of how irrationally Earhart behaved.  This was the one leg of the flight where radio direction finding was essential; she tested her equipment; she and the equipment flunked the test; she explained away the results; the next time she tried to use the equipment, she flunked the test again. 
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Jeff Victor Hayden on April 04, 2012, 08:03:59 AM
Here's another point regarding lack of comms since last transmission and possible flight to Gardner. Were they still within communication range of Itasca when no communications were heard? If comms had been made and heard by Itasca does anyone have any theories as to what AE would have said?
E.g. We're heading... Or, our position is... Or, we don't know where we are
Could they have given Itasca enough info to locate them, be it the ditching or Gardner island theory?
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Martin X. Moleski, SJ on April 04, 2012, 08:37:24 AM
Were they still within communication range of Itasca when no communications were heard?

Yes.

AE was heard on 6210 from 0418 GMT to 718 GMT in Lae (http://tighar.org/wiki/Transmission_timeline).  Since she took off at 0000 GMT, those receptions were heard four to seven hours after takeoff.  No matter what cruise speed we imagine for the aircraft, that's a long way from Lae.  If the aircraft was in the vicinity of Howland on the morning of July 2, then it pretty well couldn't have gotten further away from Howland with the fuel reserves it had than the four-to-seven hour range after takeoff.

The thought that the aircraft splashed and sank immediately after the 2013 GMT transmission (http://tighar.org/wiki/Alternative_theories#Splashed-and-Sank) is not a new thought.  Several people have written on that topic, and some searches have been done on the basis of that assumption.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Gary LaPook on April 05, 2012, 02:25:44 AM

Chater gave an explanation that made sense to him.

I find it hard to imagine that "local interference" overrode the eight scheduled transmission times that were not heard.

I understand that this is speculative.

There is a big difference between listening on the frequency and hearing nothing but silence and listening on the frequency and hearing loud buzzing sounds being caused by bad brushes on a large electric motor running in a building a mile from the airport making sparks and loud radio signals. (That is one possibility.) But whatever made the noise, called "interference," it can't be confused with silence on the frequency. Chater said "interference" not "silence" or "nothing heard,"  and the Chater report is a "primary source." And he called it "local interference" which is the type of interference made by malfunctioning electrical equipment located in the vicinity of the receiver which is different than receiving radio signals from some far away station that are coming in stronger than the desired signals from Earhart making it impossible to hear the weaker signals from Earhart.

gl
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: JNev on April 05, 2012, 06:10:37 AM
Do we know enough about Chater's abilities to know that he knew the difference?

Marty made a good point - Chater gave an explanation for the issue in his best understanding, whatever that was.  I'm not confident that Chater was that precise in his judgment on this point.

LTM -
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Martin X. Moleski, SJ on April 05, 2012, 07:38:53 AM
Do we know enough about Chater's abilities to know that he knew the difference?

I don't know enough about him to say.

He doesn't tell us what his sources were: direct participating in keeping watch in the radio station; reading logs; interviews with radio operators; hearsay.

When AE was close to Lae, the signal from the aircraft was not strong enough to overcome "local interference."  When she was four to seven hours away, they could hear her. 

Whatever the true cause of the gap may be, at the very least it shows how strange things do happen with radios.  I doubt that anyone would have predicted before her departure that it would be four hours before anyone knew that the flight was proceeding safely.
Title: Re: The Cooper Report and the 3105 Donut - why did AE quit transmitting?
Post by: Gary LaPook on April 08, 2012, 03:03:45 AM

He doesn't tell us what his sources were: direct participating in keeping watch in the radio station; reading logs; interviews with radio operators; hearsay.

When AE was close to Lae, the signal from the aircraft was not strong enough to overcome "local interference."  When she was four to seven hours away, they could hear her. 

Well I think we can all agree that the phrase "local interference" didn't just come to Chater in a drug induced haze after he dropped LSD. Either he was in the radio shack and heard it himself or Balfour told him what he had heard. If Chater  heard it himself he probably asked Balfour what he was hearing and Balfour used the phrase "local interference."

It is not surprising at all that the local interference stopped, for example, one possible explanation, the factory down the street shut down that electric motor which could make loud interference.

gl