A Peculiar RFI Problem and an Unusual Solution

Operating a remote station is never without its unique and sometimes obscure challenges as I have learned from several years of operating by remote.  When FT8 came along in recent times, I figured it would be a great way to rack up some new DXCC entities on 160 meters but I quickly realized that I had a problem.  It seems that I can operate my remote station at full legal power on 160 CW for hours on end in a contest, but the first time I fired up in FT8, the internet feed died.  Any amount of power over 400 Watts caused a complete outage that required a visit to the site to fix.  This also happened on six meters where the ERP of the mighty SteppIR DB42 can reach a whopping 15,000 Watts.

My remote station is at a ranch just outside of Petaluma about five miles from my home.  The 30-acre ranch property where I rent space has the owner’s home situated by the road at the far end of the property while the garage where my equipment is located is about a quarter of a mile away.  Comcast/Xfinity ends at the home and the only way to get internet to the remote equipment is by way of an inexpensive Ubiquiti 5 GHz link from the house to the garage.  Due to trees and buildings in the way, the small microwave units are located on fences that require 100 to 200 feet of CAT5 cable so they can be in line-of-sight locations.

An Odd Problem, Indeed!

For months I pondered this odd problem of FT8 killing the Ubiquiti link but not CW.  Ubiquiti manufactures CPE (Consumer Premises Equipment) used by wireless Internet providers to bring service to homes and businesses on a mass scale.  The big advantage is that the equipment is easy to install and inexpensive, with costs starting at as little as $100 for a complete high speed data link with a range of range of well over a mile.  Obviously, the problem was RFI related since the units are otherwise extremely reliable, so the ‘go-to’ solution is usually ferrite chokes.  But after installing an armload of them, there was no improvement indicating that this was not a typical ‘common-mode’ interference problem.  Something else was going on!

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