That's something I've never experienced, and I did a LOT of work in
downtown Chicago! I suspect something else in that interface is causing
the problem. What frequency was the RF? Were all the cables twisted
pair? What was the nature of the shield? Foil with drain, or copper braid?
I'm copying Bill on this.
73, Jim
On 4/20/2023 1:52 PM, Paul Christensen wrote:
"That's because AES Standards define Pin 1 as the designated shield
contact, with no connection to the shell. They call for Pin 1 to be bonded
to the shielding enclosure at the point of entry to ACTIVE equipment, but to
have NO connection for tie lines."
Jim, all well and good for equipment connections but consider a situation I
recently encountered: RFI ingress became issue when I needed to extend an
XLR mic cable by approximately six feet. I used an off-the-shelf 6 ft XLR
mic cable that did not bond pin 1 to the shells, nor did I expect it when
ordering the extension cable. But it was not until I bonded Pin 1 to both
the male and female shells that the shielding coverage became complete and
RFI disappeared. By not bonding pin 1 to the shells in that situation, it
leaves an unshielded gap, relying only on a Pin 1 *wire* for shielding
continuity across the XLR connectors. In my installation, the XLR
connectors float above the mic stand, not making any other physical contact.
Depending on the XLR connector manufacturer, they all have some means for a
shell bonding connection.
So, in that recent case, we truly need to bond Pin 1 to the shells and also
bond pin 1 at the equipment chassis (i.e., solution to the Pin 1 problem
citing you, Muncy, Whitlock, et. al.). Doing so makes the midpoint XLR
splice with two connectors exactly like a contiguous cable.
Paul, W9AC
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