Just recently been through all this with a NuHeat "Solo" thermostat with
built-in GFI. Running 100 watts and found the GFI tripped every time with
transmissions on 21 and 28 MHz. No other GFIs in the house were
so-affected.
All manner of ferrite beads, clamp-on ferrites, bypass capacitors etc. were
tried without success. Honeywell then replaced the Solo with a Harmony
thermostat and bingo, no more problems.
John VA7XB
-----Original Message-----
From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of Gary Mayfield
Sent: January 3, 2013 5:22 PM
To: rfi@contesting.com
Subject: Re: [RFI] Troubleshooting AFCI Tripping Due To Amateur
Transmissions
I had this issue at a previous house. The old ones didn't trip and the new
ones did. We moved them around, but only the same devices tripped
regardless of location. We tore a couple apart and found the old ones had a
capacitor from the hot to the neutral. The new ones did not (probably saved
a penny). We added a ceramic disk capacitor with a more than high enough
voltage rating to the new ones and the problem was solved. This is my
experience. I am not making a recommendation -- What you do is your
business. AC wiring can be dangerous. Always use caution! Your mileage may
vary. 73,Joe kk0sd > Date: Thu, 3 Jan 2013 15:15:53 -0500
> From: jeff@mossycup.com
> To: rfi@contesting.com
> Subject: [RFI] Troubleshooting AFCI Tripping Due To Amateur
> Transmissions
>
> 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
> VHF+suggest
> something else entirely? Alternatively, are there any manufacturers
> of RF hardened AFCIs?
>
> 73,
>
> -Jeff
> W7WWA
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