Improvising shielded ribbon cable

Thread Starter

cmartinez

Joined Jan 17, 2007
7,704
I needed to shield a short segment (about 1 foot) of 10-wire ribbon cable for this sort of connector:

upload_2017-7-7_19-17-45.png
So I naturally did some searching in Newark and Digikey and was flabbergasted with the prices per meter of this thing!

After some thought, I decided to improvise, and was quite pleased with the results. What I did is I soldered a piece of #22 jumper wire to the connector's case and ran in along the ribbon cable as shown in the previous image.

After that, I wrapped the thing in aluminum foil, and then used a piece of shrink tube to contain it.

upload_2017-7-7_19-19-19.png

In the end, I simply crimped the 2x5 header connector to the wire, and lo and behold! the assembly is working beautifully.

upload_2017-7-7_19-20-45.png


upload_2017-7-7_19-21-17.png

I'm posting this little hack in the hope that it might come in handy for someone else out there.
 
Last edited:

RichardO

Joined May 4, 2013
2,271
The only worry I have is that the aluminum will "corrode" over time. Aluminum oxide is a very good insulator.* The oxide will eventually disconnect the shield leading to strange problems.


* Except on heat sinks. ;)
 

Thread Starter

cmartinez

Joined Jan 17, 2007
7,704
I understand. I think that copper foil would be better but no where near as common. The only source of copper is from a stained glass supply store.
I have a roll of 0.001" copper shim ... but I felt that it was too thick and rigid for this application
 

RichardO

Joined May 4, 2013
2,271
I have a roll of 0.001" copper shim ... but I felt that it was too thick and rigid for this application
I can believe that.
If I was going to do it I would consider using shield braid. I have a bunch if this removed from old cables I salvaged the wires from. Braid from a large coax cable RG58 or RG59???) _might_ be big enough for your cable if you scrunch it up enough. It would require removing and then replacing one of the connectors to get the shield braid in place. :(

I just remembered that some audio cables use aluminized Mylar for the shield. I wonder how they keep the aluminum from corroding.
 

Thread Starter

cmartinez

Joined Jan 17, 2007
7,704
I just remembered that some audio cables use aluminized Mylar for the shield. I wonder how they keep the aluminum from corroding.
I work with that sort of cable all the time. They use both braid and the aluminized mylar. I guess that one single point of contact of the braid with the metalized mylar is good enough for the whole shield to work acceptably.
 

RichardO

Joined May 4, 2013
2,271
I work with that sort of cable all the time. They use both braid and the aluminized mylar. I guess that one single point of contact of the braid with the metalized mylar is good enough for the whole shield to work acceptably.
I have seen many cables that only have the aluminized Mylar -- no braid -- but there is a single, bare drain wire running along the Mylar. The drain wire would similarly make contact many places until full oxidation occurred. That does make me nervous, however, since the shield would degrade over time.

Metalized...aluminized... Now you have me wondering what the coating on the Mylar really is...
 
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