[Boatanchors] 2nd Newbie Q

[Dennis DuVall]

Ground loops can be a problem with shielded cable runs between system cabinets and consoles and especially with long runs across a site.  With short runs within a single cabinet or chassis, though, ground the shield at both ends.

(Hope I peeled enough stuff off the original messages to keep the list admin happy.)

Dennis D.  W7QHO
Glendale, CA

On Sep 10, 2014, at 8:44 AM, W2HX <w2hx at w2hx.com> wrote:

> The reason is, if you attach shield on both ends, you have a risk that the ground potential of the two ends are not the same exactly the same (Think of interconnecting two different devices together with coax. Like an exciter and amplifier plugged into different house circuits). If they are not exactly the same, a current will flow. If the current has any AC component on it, it will induce an AC signal on the inner conductor(s) of the cable which is exactly what you are trying to avoid by using a shield in the first place.  
> 
> With only one end attached, you get the shielding properties and no risk of a current on the shield. Hope this helps
> 
> 73 Eugene W2HX
> 
> -----Original Message-----
> 
> I've noticed that some construction articles involving the use of shielded cables advise that the shield be connected at only one end but they don't say which end, i.e. near or far. Also, when is this practice most useful and why?
> 
> Thanks again,
> 
> Bob  AG5X
> ______________________________________________________________