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radio wires

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nuckollsr(at)cox.net
Guest

Posted: Mon Sep 18, 2006 3:07 am Post subject: radio wires

At 10:39 PM 9/17/2006 -0500, you wrote:



 	  Quote: 	
		  I must have upset Bob N. with one of my questions of a question. So here 

goes again. During the daisy chain from the shields of the mic wires to 

the ground wire (all on the radio end of the wires) what is the best way 

to tie the pig tail into the ground wire coming from the aircraft ground? 

No I m not using a ground wire with a shield. The diagram shows the 

shields attaching to the ground wire from the aircraft ground pin. I m 

using d-subs.


	


Why would you think that I'm upset? I have x-hours a day

to devote to various activities. When I open the List postings,

I start at the most recent and work backwards. I almost never

pick up all the slack . . . there's not enough time. However,

if I attempted to pick up where I left off in the postings

and move forward, I'd never catch up. About once a month, I

discard incoming e-mails I didn't have time to address. They

number in the hundreds.



If you'll recall, I wrote a few days ago:



"Okay, got the scans. Great."



"I guess I'm not sure what the question is. The schematic shows

two aircraft ground (A/C Ground) connections to pins 4 and 15.

Wires that the manufacturer recommends be shielded have their

shield grounds returned to specific pins. They also show how

the shield can double as a ground return for mic, headphone,

speaker leads, etc. Further, their wiring suggests exactly

the same daisy-chaining technique I described in:"



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



     At some point you wrote:



"I'm wiring the harness for a Terra TX-760D radio. My question is the 

interconnect diagram shows the shield for the mic. audio, mic. key and the 

headphone attach to the ground. I plan on using the daisy chain system 

shown by Bob, however I'm confused about the shields connecting into the 

ground wire itself or do they connect to the shield of the ground wire?"



    Whereupon I was having trouble developing a

    common mental image with you and wrote:



"OOPS! I just re-read your question and I think missed

something the first time. You talk about a "shield of

the ground wire".



    Here's where I stumbled over your syntax and

    interpreted your words to paint an image of

    the ground wire as being shielded also where

    I attempted to elaborate . . .



"The drawings show single strands of wire from pins 4 and

15 to ground. Your pigtails would either solder onto the

shared solder cups or splice into the ground wires immediately

adjacent to where they drop into the crimped on pin pocket.

The ground wires are not shielded."



    So where are we with respect to achieving understanding?

    Your pigtails must make electrical connection with

    the single strand ground wires depicted in your drawings.

    You have few choices . . . The solder cups and crimp-on

    pins  won't take two wires. So, you either splice your

    pigtails into a ground wire (Strip back 1/4" of insulation

    without cutting the wire. Wrap pigtail around ground wire,

    solder and cover with heat shrink) or tack solder the

    pigtail to the side of the ground wire solder cup.



    Understand that few things "upset" me . . . the best

    way is to inject yourself between me and one of my

    customers by sowing the seeds of discontent and

    misunderstanding and preventing me from carrying

    out my duties as an honorable supplier of goods

    and services. A past poster on the List claims to

    have done just that . . . for THAT, there were

    no words I could write on these pages to describe

    my degree of upset.  Aside from overtly dishonorable

    behavior, you're not going to yank my chain and

    certainly not over a discussion on shield pigtails!



    Bob . . .

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Jim Baker

Joined: 30 Mar 2006
Posts: 181
Location: Sayre, PA

Posted: Mon Sep 18, 2006 6:10 am Post subject: radio wires

 	  Quote: 	
		       The solder cups and crimp-on

     pins  won't take two wires. 


	


Well, they will....but it ain't pretty. My Mitchell CIII autopilot 

(Bless their little hearts!) had no less than three pairs of doubled 

up wires into the back of a Centronics 24 solder cups. When one 

of the contact tabs internal to the male connector folded over I 

had to replace the Centronics connector and build up a service 

loop pigtail to mate it all back together again. So, I'd probably 

make this plea.....if you don't ever think that you'll have to 

replace a specific connector, you will. 

Jim Baker

580.788.2779

Elmore City, OK

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nuckollsr(at)cox.net
Guest

Posted: Mon Sep 18, 2006 7:04 am Post subject: radio wires

At 09:09 AM 9/18/2006 -0500, you wrote:



 	  Quote: 	
		  



 >     The solder cups and crimp-on

 >     pins  won't take two wires.



Well, they will....but it ain't pretty. My Mitchell CIII autopilot

(Bless their little hearts!) had no less than three pairs of doubled

up wires into the back of a Centronics 24 solder cups. When one

of the contact tabs internal to the male connector folded over I

had to replace the Centronics connector and build up a service

loop pigtail to mate it all back together again. So, I'd probably

make this plea.....if you don't ever think that you'll have to

replace a specific connector, you will.


	


   If it wasn't pretty, then the technology was being

   abused.  If you need to bring multiple wires into

   a connector of either the solder or crimp variety do a

   soldered, heat-shrink covered splice of the gaggle of

   wires and bring out a single lead to drop into the

   connector pin.



   The connector manufacturer guarantees stated performance

   when the product is use within limits. I've see techs

   peel out half the strands of two wires so as to crimp both

   conductors into a single pin . . . you're right, it ain't pretty.

   Splicing external to the connector pin is the way to go.



   Bob . . .

      ---------------------------------------------------------

      < What is so wonderful about scientific truth...is that >

      < the authority which determines whether there can be   >

      < debate or not does not reside in some fraternity of   >

      < scientists; nor is it divine. The authority rests     >

      < with experiment.                                      >

      <                            --Lawrence M. Krauss       >

      ---------------------------------------------------------

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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