TIGHAR
Amelia Earhart Search Forum => General discussion => Topic started by: Ric Gillespie on October 15, 2018, 09:56:59 AM
-
During the 2017 Betchart expedition to Nikumaroro led by former TIGHAR archaeologist Tom King, a TIGHAR member collected an artifact that Joe Cerniglia has independently identified as an Amphenol microphone connector. The artifact was collected under the provisions of TIGHAR's Antiquities Management Agreement with the Republic of Kiribati but it was not sent to TIGHAR HQ and we have not been involved in, or even aware of, its identification. Joe has promised to send the artifact to TIGHAR not later than mid-November along with a number of others collected during the 2017 trip.
Without notifying TIGHAR, Joe has now posted a lengthy report on the artifact on Tom King's "Amelia Earhart Archaeology (https://ameliaearhartarchaeology.blogspot.com)" blog. Tom King is no longer associated with TIGHAR. He was removed from the TIGHAR board of directors on August 31, 2018 and cancelled his membership in TIGHAR the next day.
Please review Joe's report. Is this artifact of any significance? Thanks.
-
Without notifying TIGHAR, Joe has now posted a lengthy report on the artifact on Tom King's "Amelia Earhart Archaeology (https://ameliaearhartarchaeology.blogspot.com)" blog.
Here is a permalink to "Connections of a Wayward Microphone Connector." (https://ameliaearhartarchaeology.blogspot.com/2018/10/connections-of-wayward-microphone.html)
-
Found these pictures of a Western Electric Model 13-C transmitter.
http://www.kn4r.com/kn4r/Western_Electric_13-C.html
The very last picture is interesting.
-
Once we have our hands on the artifact we should be able to answer some of these questions.
-
To label it a microphone connector is to imply that it was used on a radio. But a radio microphone connector needs three pins minimum - Mic, return(gnd), and PPT(push-to-talk). Most radio microphone use four connections so there is no electrical 'pop' when the microphone is keyed. From what I can tell of the pictures it may well be only a two-pin version of the Amphenol connector. That would make it more like a microphone as found on a sound-system. I've also seen the two pin version used for speaker connections. That would mean it could have been used on a public address system or film projector.
And yes - it's in too good of shape for being in the open on an island. Plating on these is bright nickle, and not chrome (chromium).
-
Thanks Jim. I think we’re making progress. The Coast Guard LORAN station had a 16mm movie projector and regularly showed Hollywood movies flown in by the re-supply PBYs. They would often invite the locals to come watch the movies.
-
Jim, could you provide links to some sources for this information? If we can eliminate this artifact as being from an aircraft we need to have documentation.
-
James,
I believe Joe mentions in his report that the found connector is of the one prong version. (as below) minus external threads.
https://www.surplussales.com/Images/Connectors/Microphone/cna-80-M1_1_lg.jpg
-
James,
I believe Joe mentions in his report that the found connector is of the one prong version. (as below) minus external threads.
https://www.surplussales.com/Images/Connectors/Microphone/cna-80-M1_1_lg.jpg
In his report, Joes says:
"The 80-Series connector was listed in Amphenol catalogs, parts distributor catalogs, and advertisements as a microphone connector." but the documentation he provides shows otherwise.
He says:
"The 91-Series was a deluxe model. It came with 3-or 4-prongs. The 80-Series was an intermediate model, with 1- or 2-prongs. The artifact is an example of the 1-prong variant of the 80-Series. The 75-Series was the entry level model, with 1-prong only."
Joe does not provide a photo of the prong end of the artifact but his Photo #15 appears to confirm that the artifact has a single prong. Jim Champion's statement that "a radio microphone connector needs three pins minimum - Mic, return(gnd), and PPT(push-to-talk)" is actually supported by the images in Joe's report.
Joe's Photo#5 is an image from a 1936 catalog advertising a three-prong connector as a "microphone connector." No series number is mentioned.
iIn Joe's Photo #19, the one and two-prong Series 80 connectors are labeled "contact connectors." The three and four-prong Series 91 versions are shown separately as "microphone connectors."
Unless Joe can produce documentation showing a single-prong Amphenol connector marketed as "microphone connector" it is safe to conclude that he has misidentified the artifact. It is a "contact connector" and not associated with a radio, aircraft or otherwise.
-
Found these pictures of a Western Electric Model 13-C transmitter.
http://www.kn4r.com/kn4r/Western_Electric_13-C.html
The very last picture is interesting.
Noting the Cinch-Jones style connector as seen in the photos of the WE13-C that Bill linked, do we have information on how the cockpit control head was connected to the cabling that ran to and from the transmitter in the aft section of the aircraft? I have looked at the WE13-C transmitter schematics (with and without modifications) comparing them to the photos and at the faceplate drawings of the control head but (forgive me if I've missed something) I have not seen a drawing, schematic, or photograph that shows how the control head interfaced with the wiring loom running between the two units. If the connector is not disqualified by a physical characteristic (incorrect plating for the time period, etc.), perhaps it was part of the control head/interconnecting cable loom assembly. I do note that the remnants of the shielding braid in Joe's report appear to be of the heavier, stiffer variety used in fixed radio applications (such as a wiring loom) rather than the more flexible shielding used in disconnectable items such as speakers, microphones, headsets, etc., often with a woven fabric jacket.
-
If the connector is not disqualified by a physical characteristic (incorrect plating for the time period, etc.), perhaps it was part of the control head/interconnecting cable loom assembly.
Would a single-prong contact connector work in that context?
-
Would a single-prong contact connector work in that context?
The large Cinch-Jones connector as seen in the photo of the transmitter (and referencing back to the schematic pinouts) has not only the +12 filament, +/- Dynamotor supply (forgive me, I don't recall the B+ and C- voltages), and chassis ground connections but appears to also be the connection point for the Morse key, mic audio and PTT function. The control head if I recall correctly (on the transmit side of things), has the PTT function, Morse key, and the mic jacks. None of these functions including the transmit frequency selector, or any of the receive-side items require huge amounts of current to be switched through compared to the supply voltages of the transmitter or receiver. If that is the case, smaller connectors can be and are often utilized, especially in the tight confines of the cockpit (yeah, I've got a little design experience there, too). Depending on the design of the control head, single-contact connectors such as the artifact in question could be used as the need for the larger connectors is neither needed electrically, desired spatially, or simply due to weight concerns. There could have been one for the mic, one for the PTT and/or one for the Morse Key or some combination such as a 2-pin for the mic/PTT and a 1-pin for the key, all on the back panel of the control head as connection to the wiring loom. The schematic tells us how it is wired, but a photo or other diagram would tell us how it was connected physically. As in so many cases with the disappearance, a single photograph would be the answer to many questions!
I hope this all made sense.....rushing between meetings....and wishing I had all the documents open in front of me!
-
The radio control head in the cockpit appears to have been a custom mash-up for NR16020 and no schematic seems to have survived.
If we accept the hypothesis that the single-prong contact connector found in the new village came from the back of this unit we have to explain how it could have gotten there. Did the early settlers have sufficient access to the wreck and sufficient interest to dismantle the instrument panel? If so, why haven't other cockpit-related artifacts turned up?
-
This is the forum site where I found the pictures of the transmitter. The second entry has some schematics (which I have long-since forgot how to read) that may be useful. The pictures are in the last entry.
http://antiqueradios.com/forums/viewtopic.php?t=178640
Perhaps contact with the individual doing the restoration might be in order.
-
If I understand the problem correctly, the potential use of a single-prong contact connector is in the control head in the cockpit, not in the transmitter.
-
The radio control head in the cockpit appears to have been a custom mash-up for NR16020 and no schematic seems to have survived.
If we accept the hypothesis that the single-prong contact connector found in the new village came from the back of this unit we have to explain how it could have gotten there. Did the early settlers have sufficient access to the wreck and sufficient interest to dismantle the instrument panel? If so, why haven't other cockpit-related artifacts turned up?
Ok, this takes me back a whole lot further than I care to remember, but here goes.
The switches depicted in the diagram in Ric's post appear to be a simple on/off or A/B type. They would have controlled relays inside the transmitter which would perform the desired switching. As such, these switches would not need a lot of power (12v/24v?). I'd bet they were wired with a pair of wires to a terminal block on the backside. No need for a fancy connector and there may have been space issues behind the dash as well.
Friend Weller, please check me on this. It's been a really, really long time since I've dabbled in electronics! (Pre transistor/printed circuit board era!)
The connector in question would have been suitable for use on the transmitter case, particularly if the case was located in a high traffic or exposed to feet, etc. area.
-
(eeeeep! get on the road to a meeting in Idaho or post here....decisions!)
I have several thoughts:
If I understand the problem correctly, the potential use of a single-prong contact connector is in the control head in the cockpit, not in the transmitter.
Correct....at least, that is what I am wondering as the transmitter has a nice big connector....
The connector in question would have been suitable for use on the transmitter case, particularly if the case was located in a high traffic or exposed to feet, etc. area.
.....on it in an area where space was not at as much of a premium, a connector that can be safety-wired, and that high-current connections needed to be made. Screw terminals are less than optimal in high-vibration applications compared to a threaded or bayonet-style connector. If we could only know the back of that panel assembly.....and several other things!
OK, off to Potato, Idaho. I'll be back online in a couple of hours...
-
All this makes me wonder what else may be buried in the various trash heaps in the old village.
-
If you go to the link that Bill Mangus provided to the antique radio forum, you will find a link to a Western Electric WE13C transmitter description and schematics.
http://aafradio.org/docs/Western_Electric_WE_13C_Transmitter.pdf
If you look at Figure 89 Test Bench Setup for 13B Transmitter You will see, at least for the test bench setup, a Western Electric No. 246A microphone jack was used. This jack has three connections indicated. The style of the symbol in this old schematic, corresponds to a 1/4" phone-type plug - a very early version of the 1/4" stereo phono plug common on stereos in the 70's, and the granddaddy of the 1/8" ear-bud plug on my Apple computer.
Figure 89 also shows another jack for headphones for "Side Tone". Again, the schematic symbol style is that of a 1/4" phone plug, this time the two contact style. Side Tone allows the operator to hear his the Morse Code in CW mode, or his voice as he speaks to make sure he is modulating properly.
If you make the assumption that any Western Electric control head is manufactured similar to this "Test Bench Setup", then the connectors would remain the same. I assume for the custom control panel made for Amelia's plane that there would be a preference to again use similar connectors.
1/4" two conductor and three conductor phone plugs are not the same as the Amphenol connector of the picture.
-
All this makes me wonder what else may be buried in the various trash heaps in the old village.
There are no trash heaps in the old village, or the new village for that matter. There has been a great deal of searching in both locations over the years. Each house site or government site (dispensary, co-op store, etc.) has its own collection of trash - empty glass jars, all kinds of junk including, rarely, scraps of aircraft aluminum, mostly of WWII vintage. At only a handful of sites have we found aircraft material that does not seem to match any WWII type.
-
1/4" two conductor and three conductor phone plugs are not the same as the Amphenol connector of the picture.
James, you are correct about J11, the transmitter chassis mic jack. I also notice that pin 6 of the rear chassis connector is in parallel with J11, in essense a mic extension connection. The same applies to some other transmitter functions being extended. I wonder if the single pin Amphenol connector was used on the cockpit end of the wiring loom to connect to the remote head.
Now as to why it remained or was salvaged....the wiring loom could have had more use in the value of the long length of wire as a construction material where the panel and its switches wouldn't have that same value (being careful of my use and intent of the words 'could' and 'would'). I wonder as to why the connector was pulled off of its associated wiring as it does not appear to have been cut.
Boy, is it hard to write on this teeny screen but Potato, Idaho is beautiful in the fall...
-
I wonder if the single pin Amphenol connector was used on the cockpit end of the wiring loom to connect to the remote head.
Bill Mangus wonders:
"The switches depicted in the diagram in Ric's post appear to be a simple on/off or A/B type. They would have controlled relays inside the transmitter which would perform the desired switching. As such, these switches would not need a lot of power (12v/24v?). I'd bet they were wired with a pair of wires to a terminal block on the backside. No need for a fancy connector and there may have been space issues behind the dash as well."
Now as to why it remained or was salvaged....the wiring loom could have had more use in the value of the long length of wire as a construction material where the panel and its switches wouldn't have that same value (being careful of my use and intent of the words 'could' and 'would'). I wonder as to why the connector was pulled off of its associated wiring as it does not appear to have been cut.
Wherever the connector came from, I agree that the wire it was once attached to was probably what the salvager was after as construction material. As to why the connector was pulled off rather than cut, the most likely explanation is that the salvager didn't have a tool to cut the wire with. These guys were extremely tools-poor.
-
Let me throw out another idea for consideration.
Ric's diagram of the dash control panel has a switch marked "Voice/CW", obviously used to select between a microphone or a telegraphers key as an input to the transmitter. As I understand it, wiring for a key would be less complicated than for a microphone.
We know AE/FN were not proficient in Morse Code. The dash control panel was likely made with a CW option for use by someone, presumably Harry Manning, for the first attempt. I think the most likely place for the installation of the key would have been on the nav table in the back end of the aircraft as the key would need a firm, stable mounting to be used properly. I cannot be sure of that but putting it up front with no surface to rest it on seems unlikely. This option would also require another wire pair going back for a headset for whom ever was sending Morse Code. Maybe that was too complicated and the key was used in the right seat up front where a headset/earphones were available. (Did they even have/use a headset? I seem to recall a picture of AE holding something to her ear while sitting in the left seat.)
If there was never any intention for anyone in either attempt to use CW, that argues the case that the dash controls were "standard" for a Western Electric installation and they or their successor may have pictures/plans somewhere.
If installed at the nav table that means there was a long wire running from the transmitter behind the cockpit to the table. I'm guessing that after the ground loop in Hawaii it was never removed. That may be what was later scavenged by the colonists for use elsewhere.
Without looking for pictures of any period telegraphers keys, I seem to remember the connection at the key being stripped wires held on with knurled nuts on screw posts. Joe's connector could have been used at the transmitter end.
Just another idea. . . .
Further searching. . . Harney's drawing of the Electra interior shows the transmitter located nearly underneath the nav table and a "lead to transmitter" annotated. The longest wire would then be from the cockpit location of the of the control panel back to the transmitter. Harney's drawing doesn't show a telegraphers key, as such, but that "lead to transmitter" could be for the key.
Still looking for a photo of nav table prior to takeoff on first attempt to see if key and headphones are shown.
-
Found a Western Electric Telegraph Key using this as Google search term.
-
Found pictures of transmitter and radio control panel in cockpit.
In the second picture you can see the radio control panel just below her left hand.
-
As shown in this photo taken before the first world flight attempt, a Morse key was mounted beside the right seat in the cockpit. Two wires are plugged into the unit. The connector for the top one appears to be a bit skinnier than the lower one. The Amphenol connector found on Niku looks way too big to be either one of them.
There may have been a second key at the nav station in the cabin, but the connections would be similar
-
Ah, yes! You can just see the bottom of the key in my second picture, mostly hidden by her right hand.
Those "connectors" to the key do seem a bit thin. I wonder if they're not more of a "stiffener" to keep the wires from bending at the point of connection.
I didn't follow the above discussion about what the schematics show as likely connections at the transmitter. Is Joe's find still in the running there?
-
This is the only photo we know of that shows the connections to the transmitter. The unused ("no connection") port was for the transmitter to be linked with the receiver so that the dorsal vee antenna could serve for both transmitting and receiving. Instead, the receiver on NR16020 (located under the copilot seat) was independent of the transmitter and had it's own antenna on the belly (the one that was lost on takeoff from Lae).
-
Detail of transmitter connection.
-
This is a vintage Bell & Howell 16mm projector external speaker on eBay. Model number may not be what CG was using but this certainly looks old. Second picture (not terribly well focused) shows external speaker connection cable. Looks close to Joe's find ?
https://www.ebay.com/itm/Vintage-Bell-Howell-Filmosound-179-16mm-Sound-In-Film-Projector-/153210890616?oid=232767131589
-
Second picture (not terribly well focused) shows external speaker connection cable. Looks close to Joe's find ?
Closer than anything we've seen on the Electra. Seems like a 16mm projector would be a common standard issue item for military units. Somebody knows. Some museum probably has one.
The way you identify an artifact is to find a known thing that looks just like the unknown thing.
-
It seems to me that there various kinds of radio stations on Niku at different times. I think it would be hard to eliminate all of them as possible sources of the connector.
From “Nikumaroro” by P. B. Laxton: (https://tighar.org/Projects/Earhart/Archives/Documents/laxton.html)
"They rose before dawn each day, and after the early light meal, went out under the leadership of Tem Mautake to the bush for clearing and planting. Gallagher would make his radio schedule, deal with the little office work, and follow the working parties with the native leader and acting Magistrate, Teng Koata and with his personal “boy,” young Ten Aram Tamia, a Gilbertese educated under Major Holland, G.C., at the Colony’s King George V school at Tarawa."
"The terrific impact of German and Japanese aggression and global war threw Nikumaroro into the background, and no resident officer replaced Mr. Gallagher. In 1943, however, a survey party came, and thereafter a radio navigation station was set up by the United States Forces."
"The acting Island Magistrate was that same Aram Tamia who had accompanied Gallagher as his houseboy. Next day I set out with him on a tour of inspection. A hundred yards from the house to the north was the radio station, under charge of Ten (or Mr.) Tekautu, a skillful, English-speaking, Gilbertese wireless operator. He kept a daily “Met. log” which he transmitted to Canton Island, making also two other daily schedules for official business and private telegrams. His equipment, old and needing replacement, was well and intelligently maintained. Tekautu was unmarried and a little lonely, since he was not a Nikumaroro man."
-
A hundred yards from the house to the north was the radio station
The radio shack was still standing and basically intact when we started visiting Niku. All gone now.
-
Closer than anything we've seen on the Electra. Seems like a 16mm projector would be a common standard issue item for military units. Somebody knows. Some museum probably has one.
The way you identify an artifact is to find a known thing that looks just like the unknown thing.
Looking . . . have a couple of feelers out . . . see if I get a response.
Anyone have the TO&E for a LORAN unit?
;D
-
Anyone have the TO&E for a LORAN unit?
That's Table of Organization & Equipment for you civilians. Every military unit has one. How many people, what kind of people, what kind of stuff, and how much stuff you're supposed to have (and rarely do).
-
The Morse code key in the cockpit picture shows two connectors under the key, and these appear to be the 1/4" phono plug type. There are a set of headphones draped over the seat armrest. So, it would seem that one is for the key and the other is for the headset - makes sense.
To have a CW/Voice switch on the cockpit control panel makes sense given the method of CW of that era. It is not quite the same CW that we're familiar with mid-WWII and afterwards, but technically MCW or Modulated CW. A tone-modulated AM signal was transmitted in MCW, and not just the AM carrier only. With pure CW, receivers needed a BFO or Beat Frequency Oscillator function (or other early CW reception feature) internally to add the tone to a CW signal being received. But with MCW, any AM receiver, older or newer, would receive the CW and provide an audible tone. This switch would activate the tone modulation circuits within the transmitter to create a MCW signal when the key was pressed. You wouldn't want the tone modulation to activate if you were actually using the microphone.