[CQ-Contest] [MWA] New furnace... off topic, but related to contesting

[Greg Fields]

Bob,

I put in a new Trane furnace last year that caused S7 noise. First I had 
help from Ron N0AT finding my noisy power pole then I had an S7 noise that 
kept coming and going before I figured out I had another noise problem. Here 
is what I posted to the MWA last March.

It took me two months to figure out what the intermittent noise source was. 
It finally dawned on me one day when I had the radio on as I worked on some 
paper work. Sure enough, the noise came on but, I realized it coincided with 
my new furnace going into it's heat cycle. I then waited until the next 
heating cycle of the furnace to start and sure enough, the noise started 
again. I quickly threw the power switch on the side of the furnace and guess 
what? The noise went out instantly!

A quick search of the Internet for my new Trane XV95 furnace picked up posts 
on eham documenting the same problem. Apparently the inducer motor, which is 
used to vent gases, is the culprit. I found a very good write up on it by 
N9SZ at:

http://homepages.udayton.edu/~zabarnic/RFI.html

I emailed my sales rep from Total Comfort who got the fix from Trane, which 
is a filter of some kind, a new wire for the inductor motor, and two split 
beads. The fix and installation was provided under warranty so it didn't 
cost me a thing, which made me very happy. However, after the fix was 
installed last Tuesday I noticed no difference. I took the next step and 
ordered type 43 split beads from Surplus Sales of Nebraska as N9SZ had. Like 
N9SZ I took 14 split beads this morning and put them all over the wires in 
the furnace.

I am happy to report the noise is gone now. I don't know if just the split 
beads would have fixed it or if I needed the Trane fix and the split beads. 
The bottom line is my noise is gone and I am hoping next Fall's contests can 
be heard in the clear without straining to hear through some sort of noise 
again. If you get a new high efficiency furnace from Trane make sure you 
insist they put in the RFI fix when it is installed.

73,

Greg K0OB
----- Original Message ----- 
From: "Robert Chudek - K0RC" <k0rc at citlink.net>
To: "Minnesota Wireless Association" <mwa at w0aa.org>; 
<cq-contest at contesting.com>
Sent: Thursday, December 10, 2009 3:18 PM
Subject: [MWA] New furnace... off topic, but related to contesting


The serviceman just left after installing a new furnace controller. I am 
considering replacing the P.O.S. furnace that has kept the repair department 
in an unforecasted revenue stream the last 5 years.

There has been advancements in technology in the past 17 years. This 
includes a variable speed DC blower motor upgrade from a multi-speed AC 
motor. Does anyone have any experience in the newer technologies in regard 
to my HF gear? Specifically, a variable speed DC motor sounds like it might 
be an RFI generator.

73 de Bob - KØRC in MN
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