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Intercom wiring

axlr8r

axlr8r

Well Known Member
I have recently installed a Flightcom intercom near the front panel of my RV-8.
I have also wired and installed two sets of jacks for the front and rear seats. The wiring for the jacks has been run to a point near the intercom and now I have to connect these wires to the intercom via a D Sub connector. While I was able to solder the jack wiring on a workbench, it looks like I'll have to solder the D Sub connector in the aircraft because obviously it wont fit through the small holes used to run the wires.
I don't look forward to doing this in the aircraft and was wondering if I could solder pigtails onto the D Sub (on the workbench) and then use a Molex connector to make the hookup to the jack wiring in the airplane. This would leave approx 3 inches of unshielded wiring on the end of the D Sub.
Am I asking for noise or other problems here ? I'm electrically challenged so I hope I described my problem correctly.
Thanks for any help
Steve
 
Is crimping out of the question??

If you can crimp, you can do each wire and pass the pinned wire through the hole you mentioned and then insert into the dsub connector where it will lock down nicely.
 
Another vote for crimping. Find someone with a crimper that will do D-sub pins, it's really, really the way to go. I installed an MGL EGT/CHT gauge, and ran the wires as you did, through small holes all the way back to the panel. I had intended to solder the wires one by one into a solderable D-sub connector, while sitting on the wing, contorted all kinds of ways, because I didn't want the wires a lot longer than they needed to be. I was elated when I found out a friend had the crimping tool, so I bought the pins instead and crimped them. It's the only way to go.

FYI - A properly formed crimped connection makes a better electrical contact than solder.
 
Yet another vote for crimping.

If you can't find someone to loan you a crimper, you can buy a cheap one from Stein Air (http://www.steinair.com/images/store/SAT004.jpg) for $31.00

I bought one of these a couple years ago and have used it wiring up four different RV & Glasair airplanes plus a bunch of computer stuff too, it's held up very well.

You can also get the DB connector shells and crimp pins for them from Stein.
 
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Crimp

Just because the panel came with a soldering type D-Sub does not mean you have to use. Buy or borrow a crimping tool. Buy the same size D-Sub with crimped input pins. Much easier to do.

I have the same issue with my TruTrak servo motors. I have run the wires to the wings and fuselage, but don't wont to solder in the plane. So I will be swapping the D-Sub out to a crimping style.
 
Pigtails

Even if you are crimping the pins, soldering pigtails onto the shields is still a good idea as you mention in the original post.

AeroElectric Bob has a good how-to pictorial here -

http://www.matronics.com/aeroelectric/articles/pigtail/pigtail.html

pigtail7.jpg


Just twisting up the shields and crimping them into a D-Sub pin is not good practise.

Solder sleeves could also be used.
 
Shielded wires are applicable to only one specific type of interference and rarely does any good at all with respect to noise suppression. Does the intercom manufacturer specifically indicate that shielded wire be used? If not, suggest going without and concentrate on proper grounding and isolation of the headset plugs. Read up in Nuckoll's Aeroelectric Connection, as previously mentioned.

regards

erich
 
Thanks

guys for the great advice. It all makes perfect sense. I'll borrow the tool and make the crimps as suggested. I did call Flightcom and they recommended using shielded wire. Also, they recommended no ground at the jack ends, but grounding the shields to pin # 1 on the D sub end.
Gils picture answered my question on how to do that too.
Thanks so much for the help.
Steve
 
Great tutorial

Luke. Thanks a lot.
I love this site - lot's of problem solvers here.
Steve
 
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