Hi Dan:
Good suggestion from Bill to build yourself a sniffer loop.
If you have not done EMI snooping before, I would recommend contacting a
local ham club in your area (find them via the ARRL web site) - they might
have a local member with good EMI detective experience. Otherwise try your
local contest club, I think the PVRC has a sub-chapter in VA. They might
also have some folks with good experience.
I didn't see where you mentioned what specific band(s) you're having trouble
on. I think we're assuming the HF bands. Based on the problem being only
associated with heat, not AC, and assuming you are using forced air, then
that rules out the blower motor as the source. I would suspect the ignition
circuit next, but we can only guess via email :-) - it might be that the
heating control electronics are de-energized when you select "cool", and so
it is tough to discern actual ignition circuits versus control electronics
behind the ignition circuit. Knowing what is causing the problem may or may
not help since as a homeowner you want to be careful about "lifting and
working under the hood". Anyway, I like Dale's idea of a) thermostat
wires, and b) AC line. The AC line filter may not be installed in the best
location or the right way as Dale mentions.
Ferrites will work great down to 160 m if you pick the right ones -
specifically lower permeability like Fair-Rite #31. #43 is not bad but
requires more turns of wire through a given core.
But to use the ferrite you have to know if and which cable(s) is/are the
dominant cables that are radiating and causing you trouble. Otherwise you
will end up with a bunch of heavy, expensive, ferrite-laden cables and still
have a noise problem.
Your problem is really tough to shotgun remotely, you need to make some
measurements to localize the source. Once the source is localized it is
really easy.
73
Lee
WB1ADR
-----Original Message-----
From: rfi-bounces@contesting.com [mailto:rfi-bounces@contesting.com] On
Behalf Of rfi-request@contesting.com
Sent: Sunday, October 04, 2009 3:00 PM
To: rfi@contesting.com
Subject: RFI Digest, Vol 82, Issue 3
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Today's Topics:
1. Re: Trane Furnace RFI (Bill NY9H)
2. Re: Trane Furnace RFI (Dale Svetanoff)
3. Re: Trane Furnace RFI (Scott Holisky)
----------------------------------------------------------------------
Message: 1
Date: Sat, 03 Oct 2009 15:41:38 -0500
From: Bill NY9H <ny9h@arrl.net>
Subject: Re: [RFI] Trane Furnace RFI
To: "Pawlak, Dan L." <Daniel.Pawlak@gd-ais.com>,<rfi@contesting.com>
Message-ID: <20091003204151.4C5B11B606F3@dayton.contesting.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed
we all know "" ITS HARD TO STOP A TRANE......"" good luck...
bill
At 10:26 AM 10/3/2009, Pawlak, Dan L. wrote:
>Hi,
> I'm new to this list. I have a problem with my furnace.
> I bought a new Trane furnace 2 years ago (model #
> 2TXCB036BC3HCAA) and complained to the installer that I was having
> problems with RFI on the ham bands. Some bands had more RFI than
> others. I contacted the manufacturer directly and they worked out a
> dealer with the installer to add a filter to my furnace (Variable
> Speed Inducer Kit #KIT14688). It was installed on the ac line
> inside the furnace, but did not cure the problem completely. I
> didn't take any S-meter readings before and after it was installed,
> but it did help somewhat. The RFI only happens when the furnace is
> running and not the a/c. Has there been any experience with this
> model furnace? Are there any other measures, like adding ferrite
> cores, that would help?
>TIA,
>Dan Pawlak KF4KKF
>Manassas, VA.
>_______________________________________________
>RFI mailing list
>RFI@contesting.com
>http://lists.contesting.com/mailman/listinfo/rfi
------------------------------
Message: 2
Date: Sat, 3 Oct 2009 15:52:17 -0500
From: "Dale Svetanoff" <svetanoff@earthlink.net>
Subject: Re: [RFI] Trane Furnace RFI
To: "Pawlak, Dan L." <Daniel.Pawlak@gd-ais.com>, rfi@contesting.com
Message-ID: <380-220091063205217613@earthlink.net>
Content-Type: text/plain; charset=US-ASCII
Dan,
Welcome to the reflector! From prior postings seen on here from other
people who have had to deal directly with equipment manufacturers, I would
say that you did pretty well in talking with Trane about the problem. As
you are learning, variable speed AC drives might be wonderful for boosting
efficiency, but they are not electromagnetically friendly. I am impressed
that Trane did provide a kit to reduce the interference effects. One
question about the filter kit: did the filter kit get connected to a good
ground when the installer added the kit? A "good" ground would be a solid
connection to the metal chassis or cabinet of the furnace. If the kit is
supposed to be grounded (likely) in order to work properly, lack of a good
ground (because of painted metal) could render the effects of the kit to be
minimal. I would hope that Trane gave the installer a clear set of
instructions for installation of the kit.
At this stage, I think a worthwhile question to ask is: by what means is
the remaining RFI propagating? You have the AC power line, of course, but
you also have the wires to/from the thermostat that can act as a radiating
antenna, and then there is direct radiation from the wiring within the
furnace itself. (There have been several posts in recent months about
radiated RFI from the wiring in variable speed laundry equipment -
especially from the control panels, which are largely unshielded.) I think
it is interesting that the problem only exists when heat is on, not A/C.
Assuming that the same motor is used to run the air mover blower whether in
heat or cooling mode, can you determine why the motor is "quiet" when
cooling? I am thinking that maybe the motor runs at a constant speed when
cooling. Alternatively, maybe the culprit is something other than the
blower motor.
I'd like to suggest that you rig up a "snooper loop" of some sort as a
detecting antenna. This could be a 6" diameter loop of wire rigged with a
coax connector and connected to one of your HF receivers. Put the receiver
into whichever receive mode gets hit the worst (probably SSB or AM) and
tune for max noise. Then, move the snoop loop antenna around all parts of
the furnace to see if you can find a really hot spot from which the most
amount of noise is coming.
Incidentally, keep one more thing in mind: this problem is occurring at a
relatively low frequency, not at VHF. "Ferrites", as such, will probably
not do a lot for you. If the problem can be helped with added materials,
you are likely to need special mixes designed for lower frequency
applications. But that comes later ... for now, see if you can determine
the source and why only on heat cycle. Best wishes.
73, Dale
WA9ENA
> [Original Message]
> From: Pawlak, Dan L. <Daniel.Pawlak@gd-ais.com>
> To: <rfi@contesting.com>
> Date: 10/3/2009 10:27:55
> Subject: [RFI] Trane Furnace RFI
>
> Hi,
> I'm new to this list. I have a problem with my furnace.
> I bought a new Trane furnace 2 years ago (model # 2TXCB036BC3HCAA)
and complained to the installer that I was having problems with RFI on the
ham bands. Some bands had more RFI than others. I contacted the
manufacturer directly and they worked out a dealer with the installer to
add a filter to my furnace (Variable Speed Inducer Kit #KIT14688). It was
installed on the ac line inside the furnace, but did not cure the problem
completely. I didn't take any S-meter readings before and after it was
installed, but it did help somewhat. The RFI only happens when the furnace
is running and not the a/c. Has there been any experience with this model
furnace? Are there any other measures, like adding ferrite cores, that
would help?
> TIA,
> Dan Pawlak KF4KKF
> Manassas, VA.
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
------------------------------
Message: 3
Date: Sun, 4 Oct 2009 00:04:19 -0500
From: Scott Holisky <sholisky@gmail.com>
Subject: Re: [RFI] Trane Furnace RFI
To: rfi@contesting.com
Message-ID:
<e2bdb37b0910032204y43059633p714e6dbc51c61014@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Hi Dan - My neighbor bought a new Trane, same issue. My Force antenna
is about 100' from the furnace and it was S-9 in any direction. We get along
quite well and wasn't hesitant about me putting beads on all the lines in
and out of the furnace, including the AC feed. Since the unit is in a metal
box, I drilled a hole in the case and ran a 3 foot #6 ground to the water
main. I did have my FT817 with me and could monitor the reduction which also
allowed her to see and hear the noise. I also grounded around the vibration
rubber boot, on all the corners. My thinking was any RF that leaked out the
top would be allowed to radiate from the duct work. This put the cure on the
beast. I can not hear it any longer.
Had this not worked I was going to install a commercial AC line filter at
the power entrance.
You have the best of all chances to eliminate the RFI, one step at a time!
GL - Scott N0AR member of the list for two weeks now.
From: "Pawlak, Dan L." <Daniel.Pawlak@gd-ais.com>
Subject: [RFI] Trane Furnace RFI
To: <rfi@contesting.com>
Message-ID:
<46DD8C0D7373294A9851714F7BCF9B07023A20F5@vaff06-mail01.ad.gd-ais.com
>
Content-Type: text/plain; charset="iso-8859-1"
Hi,
I'm new to this list. I have a problem with my furnace.
I bought a new Trane furnace 2 years ago (model # 2TXCB036BC3HCAA) and
complained to the installer that I was having problems with RFI on the ham
bands. Some bands had more RFI than others. I contacted the manufacturer
directly and they worked out a dealer with the installer to add a filter to
my furnace (Variable Speed Inducer Kit #KIT14688). It was installed on the
ac line inside the
------------------------------
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