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How do I terminate this shielding?

blueflyer

Well Known Member
According to the picture, I need to terminate the shielding at the transponder, but my question is, how do I physically terminate the shielding at the transponder backshell? A picture would be worth a thousand words.

wire diagram.jpg
 
Solder sleeve for sure. You have to “tease” the shield with a pic to unravel the braid. You can then reform the fine shield wires by twisting them into a single “wire”.
It’s easier than it sounds.

Do a quick google search and you will find all kinds of techniques with videos.
 
Would I attach the shield as shown in this photo (lifted from VAF)? Is that just a small screw into the backshell, or is there a nut on the underside of the fastener?

ground.jpg
 
Start with 2 conductor shielded cable. At the transponder end, strip off about an inch of the insulation, exposing the braided shielding. Push the braid back as far as you can. Close to where the insulation was cut, bend the shield and wires into a ‘U’. Use an awl or small screw driver to work open a hole in the braid at the top of the U. Use needle nose pliers to reach thru the hole and pull out the two inner insulated wires. Strip the correct amount of insulation off these wires (use a gauge), insert into pins (make/female regular or high density d-sub, whatever your connector takes) and crimp. Twist the shield, insert into crimp connector or solder-crimp (see previous post), crimp. Crimp a short length of wire into the other end (if not already there), crimp on pin and insert into any available ground pin. At the UAT end, strip back an inch as above, but cut the braid as flush as you can. Cover the cut braid with some shrink tubing. Attach the other two wires with crimped on pins.
Edit: I see I type too slowly. Yes, an option for the ground pig tale is the connector shown. Put it under any screw or bolt that is electrically attached to the metal chasis.
 
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Would I attach the shield as shown in this photo (lifted from VAF)? Is that just a small screw into the backshell, or is there a nut on the underside of the fastener?

View attachment 36458

The shield termination block is tapped, so no nut needed (at least that is how it is on my GNX 375). You should have a lock washer and washer though.

Shield termination.JPG
 
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... Twist the shield, insert into crimp connector or solder-crimp (see previous post), crimp. Crimp a short length of wire into the other end (if not already there), crimp on pin and insert into any available ground pin.....

Thanks Bob. That's what I did not understand. I'll terminate the shielding into a ground pin at my transponder. Maybe my question was vague. In any event, thanks for the guidance. My Microair transponder just has a standard DSUB backshell, so no ground points on the backshell unit like the garmins.
 
Would I attach the shield as shown in this photo (lifted from VAF)? Is that just a small screw into the backshell, or is there a nut on the underside of the fastener?

View attachment 36458

I didn't spring for the $$$ connectors with the screws for the shields. Instead, I use a #6 ring terminal and put it under one of the screws that holds the shell to the case during shell assembly. Just run the wire from that ring terminal and solder it up to all of the shield drain wires.
 
I didn't spring for the $$$ connectors with the screws for the shields. Instead, I use a #6 ring terminal and put it under one of the screws that holds the shell to the case during shell assembly. Just run the wire from that ring terminal and solder it up to all of the shield drain wires.

Oh I like that even better, thank you!
 
Solder sleeve for sure. You have to “tease” the shield with a pic to unravel the braid. You can then reform the fine shield wires by twisting them into a single “wire”.
It’s easier than it sounds.

Do a quick google search and you will find all kinds of techniques with videos.

No need to tease it out into a separate strand… https://youtu.be/uhRCUAYoSXg
 
Except……those are #4 screws that hold the connector back-shell to the case.

That is true, but the head is still bigger than the #6 terminal and it carries very little current. Obviously a #4 terminal would be better. Everybody has an extra 6 laying around but few have #4 terminals; Not a common size.
 
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