On Mon, 25 Jun 2007 11:03:48 -0400, Martin AA6E wrote:
>However, you might want to seriously look at
>your system grounding.
The problem is only on 40M and 30M.
This tells us that it is NOT a grounding problem, nor is it
related to noise or the grounding between buildings. The most
likely cause is that some wiring is acting as antenna and picking
up HIS transmitter. The obvious culprits are the 1,000 ft wire and
the power supply at either end. I also wouldnt rule out the
cables connecting the extender to his rig, other networking box,
etc.
The first thing I would try is 7-9 turns of that cable at the ham
shack end around a #43 or #31 2.4 inch toroid (FT-240). If that
doesnt fix it, add one around the power supply on the ham shack
end. If you still have problems, add chokes to those other cables
in the shack, and finally at the house.
These chokes will also suppress any common mode noise radiated by
these cables that you may be hearing on the HF bands. Ordinary
10BaseT Ethernet traffic, usually produces birdies on 30M, 20M,
15M, 10M, and 6M. 100MB Ethernet equipment is multi-mode -- that
is, it carries both 10MB and 100MB traffic, and most modems work
at 10MB on their Ethernet port.
For more detailed advice, see
http://audiosystemsgroup.com/RFI-Ham.pdf
73,
Jim Brown K9YC
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