Hi Ed,
Simply clamping a ferrite onto a wire carrying RF noise has little
effect on it on the HF bands. We must wind turns of the wire through the
core. I wrote a tutorial on this a few years ago for NCJ. It's on my
website. http://k9yc.com/KillingReceiveNoise.pdf
73, Jim K9YC
On 11/3/2018 5:39 AM, Ed wrote:
I believe we have the same HVAC unit as you do and indeed found some
unacceptable RFI coming from the unit. Lennox is actually aware of this and
will provide a filter kit (ours was at no cost) consisting of an AAC line
filter and a couple clamp on ferrites. Once installed this helped significantly
but did not eliminate the problem. I added a couple more mix 31 doughnuts in
place of their clamp-on's and also added one on the thermostat line at the
thermostat and the problem seems to have been reduced to the point where my
antennas do not see the noise.
Contact your local installer and ask for the kit or contact Lennox directly.
Ed - VE4EAR
-----Original Message-----
From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of D C _Mac_ Macdonald
Sent: Friday, November 02, 2018 6:05 PM
To: RFI Group <rfi@contesting.com>
Subject: [RFI] RFI from furnace/air conditioning
I have fairly recently gotten back on the air after a few years off. This is
AFTER I had to have our HVAC replaced. It is a Lennox SL280UH090V48B-03 which
is a variable BTU and variable speed fan system. Lots of trash, especially on
20 meter band. Does anyone here have experience with Lennox systems in general
or my specific unit ?
73 de Mac, K2GKK/5
(Since 30 Nov '53)
Oklahoma City, OK
USAF Retired 61-81
FAA Retired 94-10
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