Shielding both ends of a shielded cable can set up a ground loop. Between
two otherwise unconnected devices, you need a common grounding line IF you
plan to have their chassis at the same potential, BUT..if you can get away
with a SINGLE grounding line, you're probably better off. Why?
Ground loops are bad bad bad!!! Sure, at DC, who cares? BUT, at RF, They
can radiate and screw up an otherwise electrically healthy system.
This was learned through the process of hunting down RF sources while
doing my ever-continuing mobile HF installation.
* Scott Rosenfeld NF3I Burtonsville, MD FM19mc QRV 80-10/6/2/440 *
* 6m 80 grids on 8w * DXCC WAS WAC * QRP-L #147 * QRP ARCI #9054 *
* Charter member, Maryland Milliwatters * W3-VK on 3w mobile CW *
*** 301-549-1022 h / 301-982-1015 w ** Life is one big hamfest ***
On Fri, 2 Jan 1998, Adam B. Kanis wrote:
> Hi all,
>
> Please help me understand this:
>
> In several different circuits that have a segment where a signal is carried
> in a shielded cable, both rf and af, i've seen instructions call for
> grounding the shield at one end, but not the other. In other circuits, the
> shield was put to ground at each end. I did what was told, but left
> feeling empty - i don't like "cookbook" procedures without understanding
> the basis.
>
> I don't remember seeing this thread on the list before, but if i missed it,
> sri.
>
> 73,
> --adam, n2brt
> =================================================================
> Adam B. Kanis, N2BRT QTH: Wellman, IA (Near Iowa City) EN41ck
> adam-kanis@uiowa.edu QRP ARCI : NorCal : QRP-L: G-QRP : CQC
> Straight Key : OHR-100 40m : Carolina Beam oriented N/S
> =================================================================
>
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