[RFI] Chasing RFI

Jim Miller JimMiller at STL-OnLine.Net
Sun Oct 25 21:53:41 EDT 2015

One thing I don't see mentioned here is the effect of reflections.  

I was chasing a source that was causing garage door openers not to work all
of a sudden.  First out I thought it was a house angled across the street,
strong signal but as I got closer it was the car in on the street in front
of the house.  Nope, as I walked around the car it was the house next door
instead. And then as I walked up to their driveway, it was the next one
instead.  OK, it had been several cars in front until I got nearer them and
several houses in a row as I was nearing them, what gives?  OK, will go
behind to the next street.  Nothing, anywhere, not even back toward the
houses I had thought from the front.  I then decided to walk basically
circling the location.  Nothing and then walked down each street a half
block or so.  About the third street I started to pick up something
generally back toward the house that had called me.  Getting closer, I
started to pick up individual houses but trying to walk around instead of
directly toward them, I found that it would change houses again -
REFLECTIONS....!  OK, what is the direction that would be reflecting from
them.  Strong once I was out from behind the houses on my side that was
blocking my reception from that direction.  Got it, a garage I was looking
at the back of.  Headed that way.  Much stronger.  Bet I can even tell where
it is inside the garage.  Walking alongside the garage, nothing!  Back to
the end, nothing until I got back in the direction where I had it before -
it is a reflection again - turn around - YES. It had been another reflection
from the end of another house.  Headed over.  OK, landscaping light
transformer - nope, lighting in the flower bed, nope, box on the wall with
cable going into it ARRIS - YES.  Went back down to the fellow who called me
and his he really couldn't walk so his neighbor and some of the neighbor
kids who had thought I was weird waving the beam around until I told them it
helped me hear radio stations and showed them, all came along.  I explained
it all to the adult neighbor and when we could see the box and I showed him
the signal, there was no question in his mind what was going on.  The faulty
resident was not home.  I left and called a few days later.

Bottom line - all is well now.
Reflections will drive you crazy.

73, Jim KG0KP

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