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Author Topic: Artifact Evaluation - microphone connector  (Read 15130 times)

Bill Mangus

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Re: Artifact Evaluation - microphone connector
« Reply #15 on: October 17, 2018, 02:57:49 PM »

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.

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Friend Weller

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Re: Artifact Evaluation - microphone connector
« Reply #16 on: October 17, 2018, 04:11:57 PM »

(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...

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Bill Mangus

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Re: Artifact Evaluation - microphone connector
« Reply #17 on: October 17, 2018, 04:39:32 PM »

All this makes me wonder what else may be buried in the various trash heaps in the old village.

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James Champion

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Re: Artifact Evaluation - microphone connector
« Reply #18 on: October 17, 2018, 07:13:07 PM »

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.
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Ric Gillespie

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Re: Artifact Evaluation - microphone connector
« Reply #19 on: October 17, 2018, 07:29:23 PM »

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.
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Friend Weller

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Re: Artifact Evaluation - microphone connector
« Reply #20 on: October 17, 2018, 08:40:00 PM »



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...
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Ric Gillespie

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Re: Artifact Evaluation - microphone connector
« Reply #21 on: October 18, 2018, 07:35:22 AM »

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.
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Bill Mangus

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Re: Artifact Evaluation - microphone connector
« Reply #22 on: October 18, 2018, 08:29:51 AM »

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.


« Last Edit: October 18, 2018, 09:35:49 AM by Bill Mangus »
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Bill Mangus

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Re: Artifact Evaluation - microphone connector
« Reply #23 on: October 18, 2018, 08:42:37 AM »

Found a Western Electric Telegraph Key using this as Google search term.

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Bill Mangus

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Re: Artifact Evaluation - microphone connector
« Reply #24 on: October 18, 2018, 10:04:52 AM »

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.

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Ric Gillespie

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Re: Artifact Evaluation - microphone connector
« Reply #25 on: October 18, 2018, 10:21:15 AM »

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
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Bill Mangus

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Re: Artifact Evaluation - microphone connector
« Reply #26 on: October 18, 2018, 10:39:50 AM »

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?

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Ric Gillespie

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Re: Artifact Evaluation - microphone connector
« Reply #27 on: October 18, 2018, 11:05:42 AM »

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).
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Ric Gillespie

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Re: Artifact Evaluation - microphone connector
« Reply #28 on: October 18, 2018, 11:11:54 AM »

Detail of transmitter connection.
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Bill Mangus

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Re: Artifact Evaluation - microphone connector
« Reply #29 on: October 18, 2018, 11:22:17 AM »

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

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