Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => AmpTools/Tech Tips => Topic started by: fdesalvo on January 19, 2009, 12:12:28 pm

Title: Easier way to work with shielded cable
Post by: fdesalvo on January 19, 2009, 12:12:28 pm
After several failed attempts, I finallly dicsovered an easy way to make shielded cable runs- this may be old hat for some of you.

1. Strip outer jacket
2. Pull braid down half the length and cut around circumference with scissors. Remove any stragglers.
3. Take small length of bus wire and wrap a few turns over the remaining braid.  Carefully solder.  The jacket of the inner core is very fragile and if you apply too much heat, you will cause the shield to contact the core.
4. Heat shrink the shield lead first and then the wire up to the middle of the ground lead.

On a side note- I hate working with this stuff- the gage of the core is so thin I don't really trust it, but what can you do?  I was thinking of making my own with 22ga wire.  You know, wrap the bus wire around the jacket of some some nice 22 ga wire and heatshrink it. 
Title: Re: Easier way to work with shielded cable
Post by: tubesornothing on January 19, 2009, 01:13:26 pm
Coax is almost as much pain as wiring heaters.  Two of my least favorite jobs.
Title: Re: Easier way to work with shielded cable
Post by: RicharD on January 19, 2009, 01:30:08 pm
Strip off outer jacket.
Push the braided wires back away from the end.  It's a "Chinese finger" braid and this will loosen it up.
Now using either a tiny screw driver or a meter probe, carefully open a hole in the braid at the base of the outer jacket.
Once the hole is open, pick at it from both sides until you can get your tool between the braid and the inner conductor.
Now roll the end of the wire back making a U and carefully pull the inner conductor out.
Now pull away on the end of the braided wire making it closed and tight.

This is how I does it and I can usually do it w/o breaking more than a strand or 2.  1 additional tip is to NOT tin the shield until it's hooked in place.  Completely unbraiding the wire is not only a PITA, but it usually fatigues the wire to where it want's to break and I often lose as much as 1/2 the strands.  Cutting some of the outer strands is a NONO in my book.
If you like I'll shoot pix of the steps.

-Richard
Title: Re: Easier way to work with shielded cable
Post by: LooseChange on January 19, 2009, 03:19:45 pm
I use the shielded cable with a drain.  Much easier to deal with.
Title: Re: Easier way to work with shielded cable
Post by: fdesalvo on January 19, 2009, 03:37:20 pm
That's awesome, B.

Strip off outer jacket.
Push the braided wires back away from the end.  It's a "Chinese finger" braid and this will loosen it up.
Now using either a tiny screw driver or a meter probe, carefully open a hole in the braid at the base of the outer jacket.
Once the hole is open, pick at it from both sides until you can get your tool between the braid and the inner conductor.
Now roll the end of the wire back making a U and carefully pull the inner conductor out.
Now pull away on the end of the braided wire making it closed and tight.

This is how I does it and I can usually do it w/o breaking more than a strand or 2.  1 additional tip is to NOT tin the shield until it's hooked in place.  Completely unbraiding the wire is not only a PITA, but it usually fatigues the wire to where it want's to break and I often lose as much as 1/2 the strands.  Cutting some of the outer strands is a NONO in my book.
If you like I'll shoot pix of the steps.

-Richard

Title: Re: Easier way to work with shielded cable
Post by: RicharD on January 19, 2009, 04:29:25 pm
Strip off outer jacket.  Push the braided wires back away from the end.
(http://www.butterylicious.com/Images/Coax/01.jpg)
carefully open a hole in the braid at the base of the outer jacket
(http://www.butterylicious.com/Images/Coax/02.jpg)
pick at it from both sides until you can get your tool between the braid and the inner conductor
(http://www.butterylicious.com/Images/Coax/03.jpg)
roll the end of the wire back making a U and carefully pull the inner conductor out
(http://www.butterylicious.com/Images/Coax/04.jpg)
pull away on the end of the braided wire making it closed and tight
(http://www.butterylicious.com/Images/Coax/05.jpg)
Not a single strand broken.  This is very small Teflon wire.

-Richard
Title: Re: Easier way to work with shielded cable
Post by: bnchwrmr on January 19, 2009, 07:13:05 pm
Wow! Thanks for the reminder...
I'd forgotten about this technique.
Title: Re: Easier way to work with shielded cable
Post by: jjasilli on January 20, 2009, 11:26:07 am
That's awesome, B.

Ditto!!!
Title: Re: Easier way to work with shielded cable
Post by: fdesalvo on January 20, 2009, 12:50:09 pm
Awesome!

Do they make larger gage shielded cable?  The cable I have is very thin and it makes me nervous. 
Title: Re: Easier way to work with shielded cable
Post by: tubesornothing on January 20, 2009, 01:42:15 pm
Sure, every kind you can imagine - see belden, mouser, allied, digikey - caveat emptor:  Doug's coax is one of the lowest capacitance - a good thing.
Title: Re: Easier way to work with shielded cable
Post by: gar13 on January 21, 2009, 09:46:54 am
Thanks Buttery, for these great pictures.

I've been trying to figure out and easier way to work with shielded cable for a while, meant to post the question at some point. It was explained to me in a forum somewhere, but a few pictures are worth a thousand words.

Cheers!
Title: Re: Easier way to work with shielded cable
Post by: tubesornothing on January 21, 2009, 10:30:32 am
Here is another option
Title: Re: Easier way to work with shielded cable
Post by: tubesornothing on January 21, 2009, 10:31:18 am
voila

Title: Re: Easier way to work with shielded cable
Post by: jjasilli on January 21, 2009, 07:17:00 pm
Here is another option  Very cool too  8)
Title: Re: Easier way to work with shielded cable
Post by: Justa on January 22, 2009, 12:11:28 pm
Great pictures guys, thanks for taking the time to post them.  I hate to admit this but I was unbraiding the outer conductor lately and had forgotten the pull through method that I had used years ago.
Title: Re: Easier way to work with shielded cable
Post by: Greasehorse on February 25, 2009, 09:16:43 pm
A person could shove a piece of thick heat shrink under the loosened braid before you soldered a wire wrapped to it and get more protection for the core...