Posted by
Chris Kantarjiev K6DBG on
May 27, 2007; 8:27am
URL: http://elecraft.85.s1.nabble.com/OT-Routing-coax-near-CAT5-tp448126p448128.html
If you've got 100Mbps Ethernet in your house, you're probably already
hearing noise around 14.031, unless your antenna is far, far away
from your networking equipment. It's not just the cables, but also
the routers and interface cards that seem to spew this stuff!
For a nice discussion of common mode currents and what to do about
them, I like the paper by Chuck W1HIS at
http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdfFair-rite makes a snap-on ferrite, p/n 0443164151, which snaps
comfortably over three turns of RG-8X. I use two of them to
make a choke at the point where my coax enters the house through
a window, as well as a coil-wound balun/choke at the base of
my vertical. This seems to handle the common mode problems well
(but my vertical still picks up all kinds of RF from the neighborhood!)
DXEngineering has similar snap-on ferrites in various sizes, too.
73 de chris K6DBG
_______________________________________________
Elecraft mailing list
Post to:
[hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help:
http://mailman.qth.net/subscribers.htmElecraft web page:
http://www.elecraft.com