Forum artHighlights From the Forum

June 18 through 24, 2000


Subject: Frequencies to Frequent
Date: 6/19/00
From: Hue Miller

>July 1st. . . test
>. . . Operator [Balfour] was requested to send a long dash... She later reported no success "because the Lae station was too powerful and too close."

??? Was this test really viewed so offhandedly that she couldn't fly out 10 or 15 minutes to reduce the signal?? Amazing, if she came to that conclusion with such alacrity.

"At noon on June 30th Miss Earhart, in conjunction with our Operator, tested out the long wave receiver on the Lockheed machine while work was being carried out in the hangar. This was tested at noon on a land station working on 600 metres. During this period the Lockheed receiver was calibrated for reception of Lae radio telephone, and this was, on the next day, tested in flight. "

Anyone here thinking this sounds possibly like a clue of 2 different receivers? 600 meters, the international seagoing "calling" (initiating contact before moving to another channel) and distress frequency, was a very important and busy frequency. That figure, 600 meters, is in the forefront of consciousness like the number of hours in a day, or days in the week.

I cannot see how an expert electronics person could make such error, even if the notes were written years later. How do you forget such a thing? The "Land station" was likely a shore marine-traffic station, which would have been very often busy "working" ships and thus a good station to use to check the receiver's functioning. (If someone has a Berne List handy, it could likely even be identified, as it had to be non-distant, for noon reception of longwave.) The term "Long wave receiver" is kind of a strange way of saying "long wave receive" if we're only talking about the one WECo. receiver.

BTW, I almost hesitate to bring this up, but did she not send --- "....cannot get a null....", and not "....loop dead, can't hear anything on it....." Sounds to me she indeed could copy Itasca both on loop and wire, but just no null with the loop device.

Semi-conspiracy Theory #633-E: did someone monkey with the antenna connections from the loop to receiver at Lae? Straight wire antenna never disconnects when switched to "Loop" only, on whatever kind of "Navigation / Communication" switch the plane had? Thus, no null, and louder signal than expected with the loop functioning normally, alone.

--Hue Miller


From Ric

I have a 1937 Berne's List. Lae is not in it (nor should it be since it was neither a "shore" station nor a ship). The most likely candidate for the 500 kcs signal was Salamaua, (JVQ in the Bernes' List) which was just 20 miles across the Gulf of Huon from Lae.

Evidence of two receivers? Maybe, maybe not. First, we have to assume that Chater has the frequency right (remember that Chater is not an " expert electronics person"), but let's say that he does. We then have to assume that Earhart's WE20B had not been modified to enable it to receive that frequency, but we know that she went to considerable trouble to be able to transmit on 500 and it wouldn't make much sense for her not to be able to also receive on that frequency. Nowhere is there reference to Earhart's "receivers". The reference is always singular. I still have to come down on the side of a single receiver.

Ric


Subject: Re: Frequencies to Frequent
Date: 6/19/00
From: Bob Brandenburg

There is a plausible basis for assuming a single receiver.

Mike Everette, in his excellent analysis of the radio equipment on board NR16020, points out that AE's receiver was a Western Electric Model 20B. The designed tuning range was divided into four bands: Band 1, 188-420KHz ; Band 2, 550 - 1550 KHz; band 3, 1500 - 4000 KHz; and Band 4, 4000 - 10000KHz. However, as Mike notes, the Band 2 tuning range of AE's receiver was factory modified to cover 485 - 1200 KHz, to accommodate her original requirement for 500 KHz operation.

Mike cites a 1939 source (Howard K. Morgan, Aircraft Radio and Electrical Equipment, Pitman Publishing Corporation, New York and Chicago, 1939) which lists a Western Electric receiver model 20BA with band 2 covering 485 - 1200 KHz. Mike suggests that Earhart's equipment may have been the prototype for the 20BA.

LTM,
Bob Brandenburg #2286


From Ric

Duh. I had forgotten that Mike had come up with that. This stuff is getting ahead of me.


Subject: AE and DF, cont.
Date: 6/20/00
From: Cam Warren

"The most likely candidate for the 500 kcs signal was Salamaua, (JVQ in the Bernes' List) which was just 20 miles across the Gulf of Huon from Lae."

Lucky guess! That's absolutely right, and confirmed by other correspondence in my files. Keep up the good work, and you'll soon find Guinea Airways' (Lae) radio telephone WAS INDEED working on 6540 (and took 20-30 minutes to retune, according to Balfour, so he wasn't about to switch it to 6210 just to chat with Amelia).

Considering that revealing he "recalibrated" (Chater's word) AE's receiver to the Lae frequency (6540) was tantamount to admitting to a SERIOUS blunder, it's hard to believe he made up the story, or suffered from faulty memory (and his first documented statement was made in 1961). Cutting him some slack, he probably was going to remind AE later, but she switched her receiver to {what she THOUGHT} was 3105 before he got the chance.)

If all this is true, and I'm quite convinced that explains Earhart's inability to hear the Itasca, learning this fact constitutes THE GREATEST SINGLE BREAKTHROUGH in explaining the loss of the Electra (whether it flew on to Niku as you believe, or fell in the ocean). It hit me like the proverbial ton of bricks when I first discovered the information. Think about it.

Finally, you still seem to feel AE had only a single receiver. We'll never know for sure, pending the recovery of the plane, but there's more than a little reason to believe she had BOTH WE and Bendix RA-1. (Admittedly it seems strange, but if Bendix put up enough money to say she had one aboard, don't you think Putnam - and quite possibly Amelia herself - wouldn't be happy to accomodate?) "Motivation is a powerful clue, Dr. Watson."

Cam Warren


From Ric

I'm never going to get through to you on this, am I? Something somebody says in an interview or writes in a letter many years after the fact is ANECDOTAL and not reliable as a source of information. You keep insisting that the transmitting frequency at Lae was 6540 and it may well be true, but you have not yet provided a credible source for that information.

Not to rain on your stunning breakthrough but, as for Balfour's "calibration" of Earhart's receiver:

If he did open up the radio and fiddle with it to make sure that where it said 6540 on her dial was where she would find Lae, then yes, that was a serious error and may explain why she was unable to hear Itasca's transmissions on 3105. However, I am told by several of our radio gurus on the forum that "calibration" of a receiver in those days more commonly meant merely finding out where on the dial the desired frequency really was (as opposed to where the number might be) and marking that place with a little tick mark. That way, you didn't screw up the ability to tune in other frequencies.

Chater doesn't say what he means when he says that "the Lockheed receiver was calibrated for reception of Lae radio telephone." The fact that Earhart was able to tune in and receive the Itasca on 7500 would seem to be a pretty good indication that Balfour did NOT go in and muck about with the internal workings of the receiver.

Regarding your conviction that there was a Bendix RA-1 receiver aboard the airplane, you ask "...if Bendix put up enough money to say she had one aboard, don't you think Putnam --- and quite possibly Amelia herself --- wouldn't be happy to accommodate?"

Actually, no. I think it's clear from the removal of the easier-to-use but heavier Hooven Radio Compass that Earhart's primary consideration was weight. Why take out one radio only to replace it with another that was more difficult to use? What makes sense is what Hooven himself later alleged (anecdotal, not proof); that she saved thirty pounds by taking out his device which incorporated a separate receiver, and replaced it with the new Bendix coupler which permitted her to use the existing WE20B.

Also, if Bendix had gone to the expense of putting an RA-1 aboard the Electra don't you think thye would want its presence publicized? And yet, when describing the Electra's radio gear during an interview in Karachi during the World Flight, Earhart says there's a transmitter in the cabin and a Western Electric receiver under the copilot's seat. The "Bendix direction finder" is mentioned only as one of the instruments on the panel in front of her. That can't be an entire RA-1 receiver. She's got to be talking about the the coupler.

So far, I see lots of indication that there was only one receiver aboard the airplane and no indication that a second receiver was present.


Subject: Earhart Data from Long & Long and Lovell
Date: 6/20/00
From: Jim Hurysz

I have carefully read both Elgen & Marie Long's (1999), Mary Lovell's (1989) and other books and source materials about Amelia Earhart's last flight.

I am writing a book review of the Longs' book. I will publish the review on-line.

When I read the Longs' book I noted that --- during the last few legs of her flight before Earhart and Noonan reached Lae -- the mean time between failure (MTBF) of the Electra's engine performance measuring instruments was about 7 hours. These included the Eclipse fuel meter and Cambridge analyzer. Also engine temperature sensors.

Second, when I read the logs of Earhart's voice communications in Lovell (Appendix A) I noted that there is no indication that Earhart heard anyone on 3105 kilocycles from the time she left Lae until the plane disappeared 21(?) hours later. Could there have been a problem with the plane's HF receiver, antenna system, antenna feed line, etc. that would have prevented her from hearing transmissions directed to her on 3105?

Am I missing something? Please let me know if I am.

Thanks in advance,

Jim Hurysz


From Ric

If you've read the available contemporaneous primary sources you know that many of the Longs' statements of fact are, in reality, conjecture --- and unsupported conjecture at that. We'll be interested to read your review of the Longs' book. You'll find mine at Long Review.

You're correct that the flight seems to have heard nothing on 3105 (or 6210) at any time after its departure from Lae. The fact that a transmission from the Itasca on 7500 kcs WAS heard would seem to indicate that the receiver itself was not the problem. The explanation may be related to the loss of the aircraft's ventral antenna during the takeoff at Lae. For a discussion of that occurence see The Lost Antenna.

LTM,
Ric


Subject: Re: Earhart's Radios
Date: 6/21/00
From: Jim Hurysz

From what I've seen published here, it appears she was using a Bendix RDF radio, a Western Electric transmitter, and a Western Electric receiver. The Western Electric units were for both low and high frequency T/R.

These radios used vacuum tubes and electromechanical components (switches). Without manuals and schematics, I can't tell anything about the radios' characteristics.

According to the Longs, a radio tech did replace a blown fuse in the RDF unit's power supply in Darwin.

The radios were checked out by Pan Am radio techs before Earhart & Noonan left Miami, according to the Longs.

Any indication that the radios were checked out and received preventive maintenance in Darwin? Or elsewhere during the flight? For example, were the contacts on the band switches checked for corrosion? Corrosion on band switch contacts could cause Earhart to receive on one band and not receive on another band. Same for other electromechanical devices (relays).

Anyone who has ever restored old multi-band shortwave radios (Hallicrafters) has had an experience with oxidation and corrosion on switch contacts.

Earhart and Noonan flew through some environments (heat, humidity and dust) that are typically tough on radios.

Both Bendix and Western Electrric are still around. Western Electric is now Lucent Technologies.

Jim Hurysz


From Ric

The available evidence indicates that Earhart's radios were:

  • a Western Electric Type 13C transmitter with three crystal-controlled frequencies - 500, 3105 and 6210 kiloherz.
  • a Western Electric Type 20B receiver capable of receiving a wide range on frequencies on four bands.
  • a Bendix Radio Direction Finder coupler (not a "radio") which permitted the WE receiver to be used for direction finding.

>According to the Longs, a radio tech did replace a blown fuse in the RDF
>unit's power supply in Darwin.

Well, let's not rely on secondary sources. On August 3, 1937, in response to a request from the American Consulate General in Sydney, Australia, the Administrator of the Northern Territory (where Darwin is located) wrote:

I am in receipt of your letter of the 9th July regarding the wireless equipment attached to Miss Earhart's plane.

I referred your enquiry to Mr. A.R. Collins, Aircraft Inspector and Officer-in-Charge of the Aerodrome at Darwin, who has furnished a reply in the following terms.

...When Miss Earhart arrived at Darwin it was necessary to ask why there had been no radio communication with the Government Direction Finding Wireless Station under my control. (Miss Earhart had been advised of the facilities and the station's wave length prior to departure from Koepang.) Miss Earhart regretted that the D/F receiver installed in her aircraft was not functioning therefore an inspection of this receiver was carried out and a ground test arranged between the aircraft and the D/F wireless station. It was discovered that the fuse for the D/F generator had blown and upon renewal in M iss Earhart's presence the ground test was completed. Miss Earhart was advised to inspect fuse in event of further trouble.

During the journey from Darwin to Lae the following morning communication was established with Darwin for a distance of 200 miles from this station, radio telephone being used by Miss Earhart.

No inspection of Miss Earhart's transmission gear was carried out, this apparently being in order, therefore Sergeant Rose (who did the work) cannot hazard an opinion apart form the faulty fuse which affected only the D/F receiver.

It's not hard to see why the Longs did not quote this source in their book because it pretty well destroys their theory (which they state as fact) that the aircraft had a separate Bendix RA-1 receiver aboard for DF purposes. It's very clear from the above that the failure of a fuse in her "D/F generator" deprived her of the ability to receive any signals at all and the restoration of that fuse resulted in her ability to establish radio telephone communication. Had there been two receivers in the airplane the failure of the "D/F generator" fuse would not have affected her ability to receive voice.

Radio maintenance was also performed in Lae but we don't have detailed information about what was done.

LTM,
Ric


Subject: Re: Lae Frequency
Date: 6/21/00
From: Ross Devitt

Ric wrote:

>The receiver was not "crystal controlled" but was hand-tuned
>by selecting the correct "band" and then turning a wee crank until
>the desired frequency "came in."

Can you show me documentation or other proof of that?

Th' WOMBAT


From Ric

Okay, fair question.

There's abundant comtemporaneous literature, including schematics, of the 13C transmitter. The best is probably a sales bulletin published at the time by Western Electric called "A Three-Frequency Radio Transmitter for Airplanes" by W.C. Tinus, Radio Development Department.

The 20B receiver and the 27A remote that goes with it are described in a similar Western Electric sales bulletin published in September 1936 entitled "An All-Purpose Radio Receiver for Mobile Applications" by K. O Thorp, Radio Development Department.

The presence of these radios aboard NR16020 and the frequencies they cover are documented in a Lockheed memo dated July 30, 1937 addressed to Courtland Gross and signed by J.W. Cross.

I can send you photocopies of all of the above if you wish (just cover the copying and postage), or, if there is sufficient interest we can put them up on the website.

LTM,
Ric


Subject: Re: Earhart Data from Long & Long and Lovell
Date: 6/21/00
From: Ross Devitt

More from the same report:

Miss Earhart had arranged to change to 3104 KC wave length at dusk, but signals were very strong and the plane was then called and asked not to change to 3104 KC yet as her signals were getting stronger and we should have no trouble holding signals for a long time to come.

This one could be read either way, but nowhere in the report does it say that Earhart never replied to a transmission until:

We received no reply to this call although the Operator listened for three hours after that on an 8-valve super-heterodyne Short Wave Receiver and both wave lengths were searched.

It was presumed the plane had changed the wave to 3104, the reason for that being that Miss Earhart claimed it to be a better night wave than 6210 and had used it on her flight from United States to Hawaii previously.

NOTE: We received no reply to "THIS" call. NOT "We received no reply to any calls". It specifically says "THIS CALL". One would expect the report to say something if she had been out of touch completely!

(BTW 3104 is TIGHAR's number -- not mine. I thought she was on 3105 at night!)

I believe there is enough in the Chater report to show Earhart had 2 way comms on 6210 with Lae, but could could not hear Lae on 3105. That suggests her antenna was ok at that point out to about 800 miles. I also believe that the same antenna was used for 3105 (3105 just happens to be half of 6210 and I don't think that was an accident). So the antenna was functioning ok.

Radio interference is documented to have affected ALL traffic in the New Guinea/Australia area the day before the flight, and presumably was the same interference that interfered with Earhart's early signals until mid afternoon when they got stronger.

Itasca could hear Earhart on 3105, so her transmitter and transmitting antenna was fine then also.

Itasca lost Earhart completely when she changed to her day time frequency. This is in itself very odd considering Lae heard her on that one ALL DAY the day before, and apparently had 2 way comms with her.

Something else that bothers me from Log Jam:

TIGHAR's comments on the 06:14-15am Itasca log are in part "The signal is now stronger (Strength 3) and consistent with the estimate of "two hundred miles out" but Earhart's request for a bearing comes as a surprise. --- The Itasca's direction finder can not respond to a relatively high frequency such as 3105."

Now we all know from discussion Itasca could not DF on 3105, but where does the log notation "ABOUT TWO HUNDRED MILES OUT//APPX//WHISTLING//NW15" come in? Is not "NW15" related to the bearing? If not, what is it? NW is usually a direction. 15 is not NW, unless they meant 15deg N of W, which also seems strange. I would think they would have written "285". Curious....

Th' WOMBAT


From Ric

>I believe there is enough in the Chater report to show Earhart had 2 way
>comms on 6210 with Lae, but could could not hear Lae on 3105.

I think you make a good case for the POSSIBILITY that Earhart was hearing Lae on 6210.

>That suggests her antenna was ok at that point out to about 800 miles.

If she was hearing Lae it certainly means that the antenna she was using for voice reception was ok at that time. The evidence that the belly antenna was lost on takeoff is pretty compelling, so that would mean that the dorsal vee was being used for both transmitting and receiving. That is entirely consistent with normal practice at the time and with the capability of her Western Electric radios.

>I also believe that the same antenna was used for 3105 (3105 just happens
>to be half of 6210 and I don't think that was an accident).

No argument there.

>So the antenna was functioning ok.

Yes. IF she was hearing Lae the antenna she was using for voice reception was okay.

>3104 is TIGHAR's number -- not mine. I thought she was on 3105 at
>night!

Actually, 3104 is Chater's number -- not ours. Technically, Earhart could not transmit on 3105 but that small a difference is probably not of any consequence to someone trying to tune her in on a hand-tuned receiver.

>Itasca lost Earhart completely when she changed to her day time
> frequency (6210) .

>This is in itself very odd considering Lae heard her on that one ALL DAY the
>day before, ....

Ah, but they didn't.. she took off at 10 a.m. and it was 2:18 p.m. (over four hours later) before they heard anything from her. Chater attributes this to local interference but the fact is that Lae couldn't hear Earhart on 6210 until she was -- what?-- at least 400, probably more like 500 nautical miles away. When Earhart switched to 6210 the next morning to try to make contact with Itasca she was almost certainly a whole lot closer and, according to at least some aerial navigators with lots of experience with that frequency, within the zone where communication on 6210 is notoriously unreliable.

>Is not "NW15" related to the bearing? If not, what is it?

"NW" is "now". The "15" is in the minutes column and merely means that this was heard at 06:15. In other words,

ABOUT TWO HUNDRED MILES OUT//APPX//WHISTLING//NW 15

means, "About two hundred miles out, approximately. Whistling now. 06:15"

We're presently preparing the entire Itasca radio log for that morning, in orginal and plain English format, as a Document Of The Week. I'll let everyone know when it's up.

LTM,
Ric


Subject: Radio receiver dials
Date: 6/21/00
From: Christian D.

>From Ric
>
>Not to rain on your stunning breakthrough but, as for Balfour's
>"calibration" of Earhart's receiver:
>
>..... I am told by several of our radio gurus on the forum that "calibration"
>of a receiver in those days more commonly meant merely finding out where on
>the dial the desired frequency really was (as opposed to where the number
>might be) and marking that place with a little tick mark. That way, you
>didn't screw up the ability to tune in other frequencies.

Yes, that's also my opinion. One has to understand that at the time, marine and air radio communications were mostly done using separate transmitters, which were "rock bound", that is crystal controlled. Again, this is on the transmitter side of things. For example, IF the Lae transmitter needed 30 minutes to change from 6210 to 6540, it likely means that it was a single channel transmitter; so, if they had several crystals, they could physically swap in a 6210, for example, (the original the set came with!?!?!) and then spend some time retuning all the stages of the transmitter. IF they weren't an "official" radio station, I could well see they didn't wan't to occupy the international frequency 6210, with all the "big boys", but instead have something else, for their own local uses.

As for receivers, they were mostly tuned with a dial, and possibly some form of vernier. I even wonder if those radios had a dial marked with freqencies; possibly it was just a "0 to 100.0" scale, and a graph or table had to be used to convert to a frequency; by the way, this would be called a "calibration table". But it was EXTREMELY difficult to get any precision out of them; very hard to feel confident that, after tuning the dial to what *should* be a certain freq, one could expect to catch a SHORT transmission, without lots of "fishing" around for it. I agree it is unlikely that Lae would have done a "bench calibration", opening the receiver, and adjusting dozens of coils and caps.

They are quite likely to have meant listening to a specific transmitter with a given receiver, and doing their best to ACCURATELY read whatever numbers the dial/vernier had to be set at, so that they could be put back to that same spot as accurately as possible later...

Trying, in the field, to get ANY dial to actually display the EXACT theoretical number is against good practice. Unless the instrument has that capability on the outside of the panel. For example: when one checks a ship's chronometer against a radio time signal, it is NEVER adjusted to read what the radio time says the accurate time is; instead the difference (error) is read and recorded in a log; and that error has to be applied each time a sextant sight is taken.

In fact I wouldn't be surprised that a formal, or informal, calibration log or chart was kept by AE; just recording what the EXACT dial reading had to be, for each given actual frequency, for each given transmitter, that she listened to. Quite possibly that is all that was meant by "calibration"....

Hope this helps.

Christian D.


Subject: The belly antenna question
Date: 6/21/00
From: Hue Miller

>From Ric
>
>You're correct that the flight seems to have heard nothing on 3105 (or
>6210) at any time after its departure from Lae. The fact that a transmission
>from the Itasca on 7500 kcs WAS heard would seem to indicate that
>the receiver itself was not the problem.

And doesn't rule out Cam's theory that one channel was realigned to Lae's calling frequency.

>The explanation may be related to the loss of the aircraft's ventral
>antenna during the takeoff at Lae. For a discussion of that occurence see
>The Lost Antenna.

REAL unlikely, I say. The ventral antenna was the sense antenna, I say, and the upper antenna the comm antenna. To have the primary comm antenna below the plane would seem to make Earhart's plane the exception in aviation. Notwithstanding the fact that it would be shorter and closer to airframe (undesirable), consider the proven vulnerability. Which antenna would you rather go without?


From Ric

Okay, let's get into this. What was the function of the belly antenna? I don't pretend to know for sure, but I think that the history of the airplane might provide some clues. I'll be very interested to have your opinion on the following facts and questions.

1. When the airplane was delivered to AE in July 1936 it had a WE 13C transmitter and a WE 20B receiver, the same radios (or so it would seem) that it had when it disappeared. However, there was no dorsal antenna on the airplane at all. There was a belly antenna identical to the one that was apparently lost at Lae with a lead-in that entered the fuselage right under the copilot's seat where the 20B receiver was mounted. The only other antenna on the airplane was a trailing wire that deployed from the extreme tail of the airplane, just under the navigation light. At that time the airplane appears to have no DF capability at all.
What, in your opinion, was the function of the belly antenna at that time?

2. Sometime around October 1936 the Hooven Radio Compass was installed. This involved a separate receiver mounted on a fuel tank in the cabin, a dome-shaped antenna on the cabin roof, and another belly antenna that ran parallel to the original belly antenna but on the opposite (port) side of the airplane. The trailing wire in the tail remained unchanged.
What, in your opinion, was the function of the new belly antenna?
What, in your opinion, was the function of the original (starboard) belly antenna at this time?

3. In mid-February 1937 Earhart flies the airplane to New York to announce her planned World Flight. While she's on the east coast Western Electric installs a new dorsal vee antenna. All the other antennas remain unchanged.
What, in your opinion, was the purpose of this antenna?

4. Back in California in late February the trailing wire is moved from the extreme tail to deploy from a mast under the cabin. Right around March 1st comes the big change in DF equipment. Hooven's Radio Compass and it's domed-shaped antenna go away and are replaced by the Bendix loop over the cockpit. The belly antennas -- both port and starboard -- remain unchanged.
What, in your opinion, is the function of each of these antennas at this time?

5. The airplane goes to Hawaii, gets wrecked, and comes back to Burbank for repairs. When it come out of the shop several changes are apparent in the antenna set-up.

  • the dorsal vee has been lengthened by moving the mast forward.
  • the trailing wire is gone.
  • the port side belly antenna (that had been added when the Hooven DF was installed) is also gone.

Unchanged are the Bendix loop over the cockpit and the starboard side belly antenna.
What, in your opinion, is the function of the belly antenna at this time?

There is no change to the airplane's antenna configuration while it is in Miami or later (until the belly antenna gets knocked off in Lae.)

LTM,
Ric


Subject: Re: Earhart's Radios
Date: 6/22/00
From: Cam Warren

Two things strike me about your recent postings on the subject(s) of radio communications & DF.

1) Your apparently infinite patience in answering repetitive questions, and

2) Your grasp of the technical fundamentals is somewhat on a par with Amelia herself. (And maybe that's good - as a benchline!)

First, for the Wombat, et al -

Back in the olden days of steam-powered radios, we didn't have single-unit "transceivers" with all the marvelous "modern conveniences". Transmitters did have fixed, crystal controlled channels, receivers (by and large) were hand-tuned, which required a modicum of skill and common sense. Earhart's gear was NOT off the shelf stuff by the time she left Miami, although the WE setup WAS originally (as installed by Lockheed) airline specs.

Second -

Elgen Long's book tells us that Western Electric was unable to get their receiver to tune 500 kc, a rather incredible statement, considering WE (actually, their subsidiary, Bell Labs) modified BOTH transmitter and receiver for 500 kc use. To suggest the factory techs didn't have the "know-how" to do this is mind boggling, especially since close on the heels of the "stock" 20B receiver came the 20BB, which included 500 kc.

He's quite likely right that a Bendix RA-1 WAS installed, and I believe, AS A DF RECEIVER, in addition to the WE, which she was using for COMMUNICATIONS ONLY. This strikes us as sort of foolish -- weight considerations and all -- but hey, we weren't there to give AE our best advice. (Long's book contains a photo allegedly shot in Miami, of an RA-1 remote in the cockpit of the Electra. I see no reason to question its authenticity, but feel free to do so). Incidentally The 20B WAS capable of DF use -- the company built a nice little loop that did NOT require a coupler, and certainly not a Bendix one.

I know you remain unconvinced AE had TWO multiband receivers on board, and cite Mr. Collins' letter. Which is a bit ambiguous. "Miss Earhart regretted that the D/F receiver . . . was not functioning . . . ." (NOTE her use of "D/F"). And a later reference; " . . . . Sergeant Rose . . . . cannot hazard an opinion apart from the faulty fuse which affected ONLY [my emphasis] the D/F receiver." To most of us, that would seem to indicate there WAS another [unspecified] receiver. (Mr. Collins' expertise does come into doubt with his reference to the "D/F generator" instead of a dynamotor.)

"Conventional opinion" clings to the idea that production pieces of electronics were used, and views everything with that in mind, despite such evidence as the publicly announced revisions by Western Electric (to name one incidence). Why couldn't/wouldn't Bendix do the same with the DF setup, especially if Vince B. was going for brownie points?

And, finally, why does everyone keep thinking AE would do everything "normally" (read "21st century style")? There are dozens of examples of seemingly strange behavior, even such apparent "goofs" as failing to have an intercom between pilot and navigator. Or only "broadcasting" at half-hour intervals, or not telling anybody (on the radio) what she was really doing. Etc. Etc. So we get questions as to "why couldn't she get a null from the ITASCA?" with the subliminal thought "I certainly could have, had I been there!"

Anyway, I'm faxing you a rundown of the Western Electric equipment, which you are free to crumple up into a ball, for all I care. (After all, I'd be a "secondary source".)

Cam Warren


From Ric

Thanks for the fax. You sent a number of quotations from various primary and secondary sources regarding the WE radios. No surprises, although your allegation that the 20B did have DF capability if supplemented with a WE3A loop and a WE601A input transformer is based upon notes taken by a D.C. Mead from an undated factory manual. However, we have a five-page Western Electric sales bulletin describing the 20B dated September 1936 and it makes no mention of such capability.

You also sent a photocopy of an undated advertisement for the Bendix RA-1 receiver (the relevance of which is something of a puzzlement).

You also sent a copy of a photo from the Roessler, Gomez book Amelia Earhart -- Case Closed? supposedly showing Earhart and the Electra in Miami. Handwritten (presumably by you) is "Note: Parallel belly antenna wires!" Like so many other things in the book, the caption on the photo is just plain wrong. Numerous photos document that the port-side belly wire went away during repairs in Burbank. The photo in the book was taken some time prior to the first World Flight attempt.

You also sent a copy of a Lockheed memo dated May 6 or 8 (hard to read), 1937 describing how the V antenna is to be rebuilt by installing the mast directly over the "slanting bulkhead" but not to install a lead-in wire. This is, of course, consistent with the change that photos show was made, but I had never seen this particular piece of documentation. Thank you.

You also sent a copy of a similar Lockheed memo dated May 10(?), 1937 with two items:

1. Install V antenna on belly, in accordance with Mr. Gurr, Amelia Earhart's representative.

2. Revision to V antenna installation on top of fuselage by previous order. Re-locate transmitter inlet insulator in accordance with Mr. Gurr's instructions, Amelia Earhart's representative.

This is a curious memo because photos of the airplane taken in Burbank on May 20, the day after the aircraft came out of the shop, show no such V antenna on the belly -- nor do any subsequent photos of the Electra.

You also sent a hand-drawn diagram labeled "Gurr under belly antenna (not to scale)". It's not at all clear who drew this diagram but it does not seem to be a Lockheed document.

You also sent a copy of a page from TIGHAR's transcription of the Lockheed repair orders for the airplane. You've underlined two items:

3. Replace #41659 - Pitot masts - 1L- 1R req'd." and "9. Replace three antenna masts aft of main beam - #4??16, 4301V - 1 each req'd 41?? - 11 req'd.

You've added a handwritten note: "* Two 'tubes' and 3 masts equals 5 mounting points."

I'm not sure what your point is, but it should be obvious that the orders describing what repairs were to be accomplished were written before the work was done. Photos of the airplane after the repairs were completed make it equally obvious that the work was not done exactly as specified in the original orders.

So far I have yet to see any evidence that there was a Bendix RA-1 receiver aboard the airplane.

LTM,
Ric


Subject: The belly antenna question
Date: 6/22/00
From: Cam Warren

Several comments and explanations could be made here, time (and inclination) permitting, but I'll pass for now, with one exception.

#5 says (in part) "- the port side belly antenna (that had been added when the Hooven DF was installed) is also gone."

Now, I assume you have a photograph to verify this (situation at Burbank) but upon arrival at Miami, TWO wires run aft one from each of the pitot tubes. This verifies Joe Gurr's peculiar "Vee" (an extremely narrow one at that) that he cobbled up to provide apparently, a little more wire for 500 kc. (Weird as that seems!)(But note antenna mast installation on Lockheed work order). This is the antenna Putnam referred to, when he said Pan Am reworked the antenna, since the "two wires were canceling each other out". Pan Am converted it to a SINGLE port-side sense antenna for the HF/DF which, I'm now quite sure, was installed at Dinner Key (the Bendix "upgrade").

Cam Warren


From Ric

It didn't happen, Cam. The airplane came out of the shop in Burbank with a single belly wire antenna on the starboard side. I will send you three photos of the airplane taken on May 20, 1937 by Dustin Carter when Earhart and Noonan were loading the airplane for the run up to Oakland to pick up the cancelled "Second Takeoff" covers . We bought the original negatives from Carter's widow.


Subject: Re: Electrical matters
Date: 6/22/00
From: Hue Miller

I have to put my theory on indefinite hold while I do some more hammering and sawing. (May be building coffin.)

More grist for the mill:

RDF manualette says for D/F a good strong signal is very good. (Presumably this makes the null (minimum) position stand out that much more clearly. So, note: nix Earhart's idea of why D/F did not work at Lae. Something else going on there!!

Only firm footing is that topside V antenna for transmitter. ( Note: not usable 500 kc/s, even in lengthened form! As bright red letters on my type ATD transmitter tuning units for 500-1500 kc/s say, USE TRAILING ANTENNA ONLY. Too short and voltages developed on such a short antenna are dangerous.)

I'm thinking it was a longish run to run an antenna wire from the transmitter's TO RECEIVER post to the receiver under a seat upfront. Maybe using the belly antenna for combined sense & general receive antenna would have made "sense" from this aspect: its leadin was much shorter to the receiver. BUT how could this be, if it was scraped off, that would nix all nondirectional receive, they could only receive when switched over to the loop. Wouldn't they have commented, on discovering that fact? (In this scenario, V ant to TRANS, belly ant to RDF, RDF (pass thru wire) ant to REC HF ANT, RDF loop to REC LF ANT.)

RDF in "Receive" position acts as a 1-tube preamp between its wire antenna and the receiver. (This feature didn't have to be used, if you arranged to switch receiver to another source when not D/F'ing.)

If belly was only sense antenna, it could be dispensed with. Might not even merit mentioning to Itasca or Lae.

This scenario still fits, as a possibility:

  1. V antenna to TRANS
  2. Trans (switched ant) to REC HF ANT (but is this run too long?)
  3. Belly ant to RDF
  4. RDF output (3 wire shielded) to rec loop inputs (here's where my theory took off: connected here to LF ANT )
  5. RDF wire antenna pass-thru not connected to anything

But I'm not convinced. I am still tossing transmitters, receivers, antennas, and cables up in the air, hoping they'll land in a pattern that makes sense. Ideas, anyone?

RDF manualette sez RDF was at home using either comm antenna wire or dedicated sense wire antenna connected to its A post.

What, what was the advantage in having the belly antenna??????

Being so weight conscious, would AE have kept the belly antenna on, if it was doing nothing, connected to nothing??

Maybe sketching some of this layout stuff out, would help.

Hue Miller


From Ric

Despite the U.S. Army Signal Corps' best efforts, I'm not a radio guy (as Cam has already noted) but the scenario that makes sense to me is, as you suggest above, that the belly antenna was a combined general receive and sense antenna. It's loss on takeoff would almost certainly not be audible or "feelable" by the crew. Its absence would tidily explain why AE heard nothing transmitted by the Itasca until she tried to DF on 7500 and switched over to the loop which was, unbenownst to her, the only receiving antenna she had.

Of course, this scenario only works if she heard none of Balfour's transmissions on 6210 either and, as Ross has pointed out, Chater's comments on this can be interpreted either way.

The loss of sense capability for the DF would not be an issue because she never got a null anyway, but the loss of voice reception was, of course, a major factor in the disappearance.

Would AE have mentioned not having received anything from Lae? Would she have assumed that hearing nothing meant that she had a problem with her receiver? I doubt it. As far as I can tell she rarely received anything from anybody anyway.

LTM,
Ric


Subject: 13C or 13CB Transmitter Installed in Electra?
Date: 6/22/00
From: Jim Hurysz

According to Aircraft Radio and Electrical Equipment, (pages 144-151) the WE Model 13C transmitter covered 2000 to 6500 KC. The WE Model 13 CB covered 2000 to 6500 KC and also 325 to 500 KC. The 13 CB also allowed for CW (Morse Code) operation.

The 13 C and the 13 CB could operate on three crystal controlled frequencies. The crystals were in crystal ovens. Both transmitters were configured to transmit on any 3 frequencies in the range the transmitter could transmit by installing the appropriate crystals and the appropriate "interstage transformers" in the transmitter. The 13 CB was supplied with a 5 lb loading coil. The 13 CB also had an adjustable tuning unit between the final amp tubes (a pair of WE 282As) and the loading coil. The output from the loading coil could be matched to a trailing wire or other antenna. The 13C used final stage tuning inductors instead of the loading coil and adjustable tuning unit.

It appears that considerable "trial and error" effort had to be expended to couple the 13 C or 13 CB transmitter to an aircraft's antenna for optimum performance. The recommended way of doing this was to add or subtract capacitance.

Transmit / receive was done at the transmitter, using relays. The relays were normally open and were closed by the push-to-talk switch on the pilot's micrpohone. Remote frequency (crystal and inductor) selection was accomplished mechanically through a "geared tachometer shaft."

Although Aircraft Radio and Electrical Equipment was published in 1939, and appears to have been written in 1938, there is nothing mentioned about configuring the 13 C or 13 CB to transmit above 6500 KC.

Jim Hurysz


From Ric

Has anyone suggested that Earhart could transmit above 6500 KC?


Subject: Re: The belly antenna question
Date: 6/22/00
From: Cam Warren

If you'll reread my message, I think you'll realize that I expected you to have a Burbank post-repair photo showing a single wire (I have one also, but it's hard to tell). I've been led to believe the Nat'l Archives photo in the Roessler book was authentic -- and it obviously DOES show the double wire arrangement. If you ARE sure the photo ID is incorrect, I'd appreciate the correct info, and will willingly concede. Further, if you are in possession of a known "Miami arrival" picture showing the single wire, that would come close to nailing the coffin shut re the "Gurr Vee". But --

Two small problems before we write off my theory ("impression" would be a better word).

1) As I'm sure you know, AE complained her radio didn't work enroute Miami. Putnam wrote Mantz (as I recall) and said the Pan Am techs had found the two wires were canceling each other out (consistent with the goofy Vee) and when they reduced it to a single wire, reception was much improved (I'm paraphrasing the letter, which I don't have in front of me).

2) How do you explain the work order -- printed in YOUR book, and I have a copy of the original Lockheed document -- that clearly indicates the THREE antenna masts aft of the pair of pitot tubes? You SAY that the work orders weren't followed exactly, which sounds like a generic cop-out if I've ever heard one. Do you have "scientific" evidence to support that conclusion??

And a final comment re Chater's use of the word "calibration", which I think you -- and several others -- are attaching momentous significance to. A reasonable conclusion would be that he was misusing the word (in a technical sense). I'd suspect he meant "retuned". Don't forget, Mr. Chater was -- like Amelia -- not overly fond of, or well acquainted with aviation radio. (Ref: Wings of Gold by Sinclair)

Cam Warren


From Ric

Cam, with all due respect, I think we're wasting each others' time.

I send you not one but three Burbank post-repair photos showing a single wire and you say, "I expected you to have a Burbank post-repair photo showing a single wire (I have one also, but it's hard to tell)."

You say, "I've been led to believe the Nat'l Archives photo in the Roessler book was authentic -- and it obviously DOES show the double wire arrangement. If you ARE sure the photo ID is incorrect, I'd appreciate the correct info, and will willingly concede." Nobody is questioning the photo's authenticity. It obviously shows Amelia and her airplane. What is incorrect is the Roessler/Gomez caption saying that it was taken in Miami. Antennas aside, the photo shows AE standing on the wing beside the cockpit wearing her plaid shirt, silk scarf and leather jacket. Must have been a chilly May in Miami.

I send you three photos showing that the airplane came out of repair with only two antenna masts aft of the pitot tubes and you ask me if I have scientific proof that the repairs calling for three masts were not carried out according to the original orders.

You've convinced me that I can't convince you of anything, so let's not burden each other and everyone else with these exercises in futility.

LTM,
Ric


Subject: Re: Earhart's Radios
Date: 6/23/00
From: Hue Miller

[Note from Ric: I'll answer Hue's question as he asks them]

>From Cam Warren
>
>1) Your apparently infinite patience in answering repetitive questions,

Well, so what? Are we running out of space?

From Ric: No. The issue is time. We need to move the investigation forward. If the forum had a fixed and constant body of subscribers we wouldn't have people endlessly raising questions that have already been answered. We do have a section of FAQs on the website, and that helps, but we can't cover everything there. Repetitive questions are a fact of life.

>(Long's book contains a photo allegedly shot in Miami, of an RA-1 remote in
>the cockpit of the Electra.
>
>.....cite Mr. Collins' letter. "Miss Earhart regretted that the D/F
>receiver . . .was not functioning . . .

Well, I have to side with the "2 receivers". Such photos plus the comments seems to make a strong argument. I think if you don't accept this, you are forcing the quoted descriptions to a poor fit.

From Ric: I disagree.

>From Ric
>
>No surprises, although your allegation that the 20B did have DF capability if
>supplemented with a WE3A loop and a WE601A input transformer is based upon
>notes taken by a D.C. Mead from an undated factory manual. However, we have
>a five-page Western Electric sales bulletin describing the 20B dated
>September 1936 and it makes no mention of such capability.

The last sentence does not particularly disprove anything. A star witness is the different HF and LF antenna connections. Without D/F use intended, there is no need for different inputs. ( I can explain this if need be. I can also quote schematics for contemporaneous gear.)

From Ric: I don't have the expertise to comment on that.

>You also sent a copy of a similar Lockheed memo dated May 10(?), 1937 with
>two items:
>
>2. Revision to V antenna installation on top of fuselage by previous order.
>Re-locate transmitter inlet insulator in accordance with Mr. Gurr's
>instructions, Amelia Earhart's representative."

Does this further point to the top V antenna as (at least) serving the transmitter?

From Ric: There's little doubt that the dorsal V served the transmitter. The lead-in enters the fuselage right where the transmitter is mounted.

>This is a curious memo because photos of the airplane taken in Burbank on
>May 20, the day after the aircraft came out of the shop, show no such V antenna
>on the belly -- nor do any subsequent photos of the Electra.

Maybe somebody in the shop said, "Hey, this is a waste of material, time and money" (because it won't gain you anything.)

>I'm not sure what your point is, but it should be obvious that the orders
>describing what repairs were to be accomplished were written before the
>work was done. Photos of the airplane after the repairs were completed make
>it equally obvious that the work was not done exactly as specified in the original >orders.
>
>So far I have yet to see any evidence that there was a Bendix RA-1 receiver
>aboard the airplane.

What about the photo claimed to show the RA-1 control box? So you would assume she had the RA-1 removed somewhere down the line?

From Ric: No I would not. The photo touted by Elgen Long as showing a Bendix RA-1 remote mounted in Earhart's cockpit in Miami shows a black box with illegible markings on it mounted in the cockpit of some Lockheed Model 10. I've seen nothing that identifies the box as a remote for an RA-1 nor can I see anything in the photo that identifies the airplane as Earhart's or the location as Miami.

BTW, in 1937 the RA-1 would be considered a very impressive and expensive piece of equipment. ( Cam: any prices?) That 'might' be a factor in keeping it on -- the respect with which it was regarded.

Hue Miller


From Ric:

And you don't find it odd that after Bendix went to such great expense to equip the airplane with such prestigious equipment, no one -- not Bendix, not Putnam, not Earhart, nor anyone in the press ever mentioned that it was aboard?

Pardon me, but this whole question of a second receiver seems like a classic example of the kind of wrong-headed methodology that has plagued so-called Earhart research for over 60 years. Somewhere along the line somebody thought up the possibility that there might have been a second receiver -- a valid hypothesis to consider. Rather than testing the hypothesis by gathering the available contemporaneous primary source evidence (of which there is none, as far as I can tell) they interpreted ambiguous references as supportive of their theory, ignored the contrary evidence (of which there is plenty) and then flatly stated that a particular make and model of radio was the second receiver. This kind of specificity enhances the appearance of credibility, especially if it comes from a "respected" source.

I'll gladly accept a Bendix RA-1 aboard the Electra if somebody can show me that one was there, but until then I have to go with what the evidence shows.

LTM,
Ric


Back to Highlights Archive list.

About TIGHAR Join TIGHAR TIGHAR Projects TIGHAR Publications Contract Services
The TIGHAR Store Blog TIGHAR Forum Contact TIGHAR TIGHAR Home

Copyright 2018 by TIGHAR, a non-profit foundation. No portion of the TIGHAR Website may be reproduced by xerographic, photographic, digital or any other means for any purpose. No portion of the TIGHAR Website may be stored in a retrieval system, copied, transmitted or transferred in any form or by any means, whether electronic, mechanical, digital, photographic, magnetic or otherwise, for any purpose without the express, written permission of TIGHAR. All rights reserved.

Contact us at: info@tighar.org  •   Phone: 610.467.1937   •   JOIN NOW