On 1/3/2013 3:15 PM, Jeff Stevens wrote:
First we are dealing with two issues, one of diplomacy/cooperation and
one of a technical nature.
Before calling the ham a prick for not cooperating (such do exist) I'm
interested in why he has chosen not to cooperate. How was he first
notified there was a problem? Did they get along prior to the RFI?
IE: is there any history between the ham and neighbor, or between the
ham and neighborhood, or any other neighbors. Normally when some one
doesn't want to cooperate there is a reason and it's quite often
from/because of the initial contact or some history within the
neighborhood or even prior history from some other location.
As to the problem, it sounds to me as if there is a grounding problem as
a properly grounded GFI shouldn't care about RF. Are perchance both
houses on the same transformer? (Hope not as that could be a major
problem.) are the grounds properly tied to the panel. Are they
contained in the Romex the full length? Is any thing not on that
circuit tied into the ground. Does that ground tie into any other
grounds such as water pipes? Many Electricians tend to think ground is
ground and all are created equal and of course when RF is involved they
aren't. Does the neutral have a good low resistance connection back to
the pole transformer?
73 and good luck,
Roger (K8RI)
A friend of a family member is experiencing an apparent RFI issue which is
causing his code required AFCI outlets to trip, apparently due to his
neighbors amateur transmissions. This is in the Southern New Hampshire
area. Unfortunately, unlike many of us in the amateur community (who would
relish the opportunity to troubleshoot such an interesting RFI issue) the
operator seems unwilling to provide even a basic level of assistance. To
clarify, this is a situation where a licensee is apparently causing
interference to a Part 15 AFCI in his neighbors house. While the licensee
may not be under any legal obligation to help troubleshoot the RFI issue,
I'm hoping we can come up with a solution for the neighbor. The neighbor
has apparently spent hundreds of dollars in material and labor to have an
electrician attempt to remedy the problem without success. Several brands
of AFCIs have been tried with no improvement. The licensee has been
unwilling to provide even basic assistance such as what bands he operates
on, what power levels he uses, or what times he operates. I'm looking for
suggestions on how to reduce the RFI which the neighbor's AFCIs are
experiencing which will hopefully eliminate the erroneous AFCI trips.
The little information we know about the licensee is that his antenna
systems are wire only. There appear to be no HF/VHF beams or highly
directional antennas on the property. I have not seen the antenna systems
myself and these are only third party observations. In addition to being a
licensed amateur, the operator is apparently an RF engineer as well. With
this in mind, it's likely the licensee is operating on HF of MF, possibly
QRO.
The only suggestion I've been able to come up with on my own was to build a
choke by running the romex wire leading to the neighbor's AFCIs through a
large toroid of the appropriate material. This would simply be an attempt
to prevent any induced MF/HF current on the electrical system from reaching
the AFCI while allowing the 60Hz AC current to pass through unhindered. Of
course, we aren't sure what frequency the licensee is operating on so we
don't know what material to select. Our assumption that this is MF/HF
interference may not even be correct -- the licensee may be operating on
VHF+. Is this choke idea an appropriate path to follow or should I suggest
something else entirely? Alternatively, are there any manufacturers of RF
hardened AFCIs?
73,
-Jeff
W7WWA
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