Topband: Elimination of Treadmill RFI on 160 meters

[Jim Brown]

On Thu,1/29/2015 11:18 AM, Tim Shoppa wrote:
> A deep "4 inch box"? Add extension rings if necessary? Ganged outlet boxes?

Slide #6 in http://nccc.cc/pdf/CQP-RFI2013-2.pdf shows how I mounted a 
20A line filter in deep multi-gang boxes. Each box is sized to hold a 
single duplex outlet or switch. I've forgotten the correct name for 
them, but they're in the big box stores, about $2 per section. All it 
takes to gang them is remove one side cover of the end boxes and both 
side covers of the interior boxes and screw them back together. I bought 
these at Home Depot. I later found a cover for the rest of the box -- 
some of the less common stuff like multi-gang covers I had to buy online 
from amazon, etc.

Another good way to do it is to buy a suitable length of ordinary 
extension cord (same big box store), break it close to the male plug 
connect the two ends to the line filter, going in and out of the box 
with compression fittings, and winding a common mode choke on the longer 
output side of the cable. I've done that with a cable where the output 
went to a multi-output strip or 3-way split.

When you're wiring to the filter (and outlets) ALL THREE WIRES MUST be 
connected on both sides.

Here's a link to ARRL's page about grow lights.

http://www.arrl.org/grow-light-rfi

It includes a link to line filters that W0IVJ and W0QE have developed. 
 From the spectrum sweeps, it's not clear to me that their filter goes 
down below 40M.

73, Jim K9YC