PDA

View Full Version : Shielding, terminate or not?



wizprod
27th January 2015, 03:36 AM
I've heard quite a few people say that a shielded wires should only be terminated in 1 end.

But looking at Ethernet STP cables, they are indeed terminated in both ends.

So, why and why not terminate?

Brucey
27th January 2015, 01:03 PM
I guess Ethernet cables are have shielded connectors at both ends so people don't have to think about which end plugs into which?
I'm not up with the physics of why, but, You only need to terminate one end of your shield and that should go back to the -ve terminal of the battery.

londonguy
27th January 2015, 02:23 PM
Ethernet cables are designed for long runs, up to 100 meters and for best performance you want the shortest path to ground so both ends are terminated. Ethernet is balanced so it's not affected by ground loops as much as unbalanced connections and ground loops are the main issue with terminating both ends.

In a typical FPV aircraft scenario it doesn't make any sense because if you drain both ends then you are actually adding a longer path to ground. So no point.

wizprod
27th January 2015, 03:27 PM
On rc groups I got a different answer, which I think makes quite a lot of sense:



If there is another ground-connection: terminate at one side only, to avoid ground-loops.
If the "grounds" of the 2 ends of the shielded wire are not connected by another way: terminate at both sides.


http://www.rcgroups.com/forums/showthread.php?t=2334172

Let's say an alexmos board IMU... should I terminate in both ends (at the board, and at the imu) ?