[RFI] HomePlug Experience?

[Don Moman VE6JY]

On a related matter to CAT5 radiation (not a HomePlug issue), I have  noise
issues on 10m and 15m from a co-located internet provider (ISP).  Their
equipment is on a 150 foot tower that has a stack of 10m yagis.  10m is
basically unusable. The 15m stack tower about 300 feet away when pointed at
the internet/10m tower hears it at S9 levels.  The noise is broadband with
stronger carriers interspersed.  The noise disappears when the 15m antennas
are rotated or the ISP is off the air.  20 and 40m yagi antennas at a
similar distance do not hear any noise.

The ISP installation has 4 runs of CAT5 shielded (drain and foil grounded at
bottom only) to their equipment at the 140' level. They seemed to be well
aware of the proper way to wire the pairs of the CAT5 so it doesn't radiate
(as much).  24 vdc power is supplied by me from batteries (no switcher
involved).

The current plan (and they are willing to do what they can to help reduce
the noise) is to install metal conduit up the side of the tower and run all
the CAT5 inside that, leaving only a very short piece exposed (and even that
could be covered with some flexible conduit)  The rigid conduit will be
clamped to the tower every 10 feet or so and the lengths will be joined with
the usual couplers and set screws so as long as they are tight the shielding
should be relatively complete.

So I guess my question is if this method will solve the noise issue or if
additional things should also be done at the same time ?

73 Don
VE6JY


On Thu, Oct 7, 2010 at 11:39 AM, Jim Brown <jim at audiosystemsgroup.com>wrote:

>  On 10/7/2010 3:42 AM, Hare, Ed W1RFI wrote:
> >> I do know the CAT5e and CAT6 do radiate making the use of 2-meter HTs
> >> >  problematic within about 75 feet of the cable runs.
> >
> > That almost sounds like something could be wrong. At ARRL HQ, we have an
> extensive Ethernet and radio operation continues pretty much noise free.
>
> I don't use wired Ethernet here in CA, but I did in Chicago.  2M HTs
> heard a LOT of noise in close proxmity to the CAT5 wiring in the room
> that was my combined shack/office, and I did NOT notice an improvement
> when replacing low quality stuff with Belden  Mediatwist (a very high
> quality CAT6/7 cable).  My noise level there was far too high to hear it
> in a roof-mounted vertical 50 ft or so from that wiring.  This is
> broadband noise I'm talking about, not the modulated carriers that
> clustrer around 14030, 21052, etc., which can be effectively reduced by
> multi-turn ferrite chokes.
>
> 73, Jim K9YC
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