[RFI] RFI suppression cores for 147 MHz

[Jeff Stevens]

On Wed, Feb 27, 2013 at 12:22 PM, Jim Brown <jim at audiosystemsgroup.com>wrote:

> One thing you might try is using shielded CAT5/6/7 cable.  One thing I
> tried that did not help at all was to use Belden's premium Mediatwist
> cable. It's excellent cable, and it did improve error rates on my network,
> but not RFI.
>

I too have had my fair share of VHF interference from Ethernet over the
years.  While I've considered using shielded twisted pair, I don't know how
it's supposed to be installed.  While I've worked professionally (and
extensively) with UNshielded twisted pair, I've seriously never seen a
shielded product in use -- except in my own home where I've experimented a
bit.  It's never even mentioned.  There isn't a readily available reference
standard I can find which says how the shield is supposed to be dealt
with.  While it's easy to find core equipment such as switches and routers
to accommodate shielded terminations (they ground the shield), it's rare to
find a computer, NIC or even a patch panel (or punch-down block) designed
to interface with STP.  I don't know.  Perhaps STP is only supposed to be
grounded at the switch?  It seems to me, however, that having STP grounded
at one end alone would create spaghetti mess of 'antennas'.  Then again,
maybe grounding both ends would just cause strange ground loop issues?
IDK.  I just don't know how it's supposed to be installed.

Does anyone know what document describes the standards for installing STP?
I'm not concerned about the actual cable and terminations, just what to do
with all those ungrounded ends -- if anything?  What do I do with end
equipment an patch panels which don't make contact to the shield?

-Jeff
W7WWA