Hamid -

 

>If you are going to terminate a shield in a wire that goes into a pin, you >are wasting your effort.  The wire and the pin is going to have a high >enough impedance at high frequencies to be rendered totally useless.

 

Can you quantify those high frequencies? The wire termination is supposed to be no more that 2" long. To what frequencies will it be susceptible?

 

>A single terminated shield does provide protection against ground loops >created by poor wring or poorly designed avionics.

 

Isn't a double terminated shield the definition of a ground loop?

 

>There is only one way to terminate a shield:

>To the back-shell of a properly grounded connector.  Unfortunately you

>are SOL if the idiot designing the avionics does not know about proper >grounding. Meaning that if the avionics designer does not provide a grounded connector body or uses a connector that does not have a groundable >backshell available.

 

This sounds like PS Engineering. Their backshell is plastic, and their installation manual states that all the shields are to be single-terminated by daisy-chaining them together and connecting them to the ground pin on the DB25 connector. Is their installation manual wrong?

 

http://www.ps-engineering.com/docs/PM3000_IM.pdf

 

 

Bob Nuckolls' Aeroelectric website has an article describing how to terminate shielded cable. Is his method incorrect?

 

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

 

 

Adam Molny

Lancair #151