View Single Post
Old 01-04-2008, 06:51 AM   #3
W4DRR
Junior Member
 
W4DRR's Avatar
 
Join Date: Dec 2007
Location: Blue Ridge, VA
Posts: 10
Default

I have a WFCO 55 amp converter in my Outback, and yes it is quite noisy, with harmonics every ~35KHz or so. It stays in our driveway, plugged in, and not very far from one end of my 75/40 dipole, so I am very familiar with all the spurs and harmonics. I have installed several "industrial strength" clamp-on ferrites on all the wires going into and out-of the converter, including the main AC feed. They are quite large, with some being mix #43, and the others mix #31, both good for HF suppression. Again we are talking "industrial strength" here, not el cheapo Radio Shack grade. Results: not that good. It has lowered the noise somewhat, but still not enough. My take on it is, much of the noise is directly radiating from the converter PCB and it's cheap magnetics, not just conducting on the wires. The only fix may be completely shielding the converter in a steel box.
And as Bill, N7OQ, mentioned, that bathroom vent fan is really bad. That thing could never pass Part 15 certification. Though I haven't tried it yet, a little in-line filtering on it would go a long ways. Something like a common mode choke and a couple of ~0.1uF caps maybe, right at the motor.
__________________
73, Bob
RV: 2005 Outback 23RS
TV: 2009 Toyota Tundra Crewmax 4x4, 5.7L
Licensed since 1969
ex-W0DRR, W6DRR, WB8DRR, WN8DRR
W4DRR is offline   Reply With Quote