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Low noise triax cable conductive insulation layer?

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ivaylo:
So I buy some of this triax cable - http://www.ebay.com/itm/10m-33-ft-Low-noise-Triax-Cable-50-Ohms-RF-Medical-aerospace-camera-NEW-/201098156225 . All looks good and everything, low-noise, teflon, blah, blah, blah... Tried mounting them a few different ways (triax connectors, crimping some pins to them, soldering directly to a PCB, etc.) until I notice that on some of my connections the resistance between the inner shield and the center wire measures ~50-100KOhm. Drove me crazy... I disassemble the connection and all is back to insulating properly.

Turns out the inner most insulator (around the center wire) consists of two layers - black semi-conductive one and a white proper insulator (see pictures). And the black stuff is not a tubing kinda thing which you can just cut and slip off, it's rather molded on top of the real (white-ish) insulation bellow.

So my question is - what would be the proper technique to strip/mount these cables? I had a moderate success by sanding off the black stuff with a Dremel felt tip tool (second picture) but that is clumsy. How would you strip the center wire such that it's guaranteed the black stuff never touches it (or the connectors attached to it)? Or how would you strip the black stuff only? Asked the seller for a spec or application note for this cable but still no reply...

Appreciate your help!

skipjackrc4:
I don't know, but I'm interested in finding out.

robrenz:
Here is a method I used in this video. This link starts at the point where I am cutting the cable
http://youtu.be/o13e5LWsPTI?t=21m47s

ivaylo:
Oh, I know that video by heart :) Thanks for posting it btw, I am doing a similar project for a two channel SMU, will hopefully post results soon. My cable is much thinner though. Center wire with the insulation (black+white under) is only 0.9mm, with the black stuff peeled off it's 0.85mm. So how do I get rid of the black thing only? What I missed on your video is that your cable also has this black layer and I am going to guess now that it was conductive too (did you measure it by any chance?).

Richard Crowley:
It is that black conductive coating on the inner dielectric that is the major contributor to the "low noise" performance.

Do you have a commercial brand/part number for the cable?  Can you Google recommended compatible connectors?
You can work from there how they intended to terminate this stuff.

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