well, to get some basic data like frequency you can get an sdr like the qs1r
and set it to record the whole spectrum for some period when the AFCI is
tripping. you wouldn't have to record for long, just for a few seconds around
the time they trip and then view the spectrum to see where he was
transmitting... of course if you recorded long enough you could demodulate the
signal and see what mode he was using and get the callsign to verify who is
doing it. then you could get some rough idea of power levels by using a known
mobile antenna near the neighbor's location and compare signal levels.... that
would at least give you a starting point, then you could park the mobile
station at the house and see if you can replicate the problem.
if you do go the filter route i would look more at capacitors across the power
terminals, its probably easier to install them than trying to wind coils and
hide them in the walls.
Jan 3, 2013 03:16:14 PM, jeff@mossycup.com wrote:
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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