[RFI] How far does RFI travel?

[KD7JYK DM09]

It depends...

I tracked down one source that covered 18 square miles.  I suspect it 
covered a much larger area, but after covering that area, I found it and 
looked no farther.

Although not RFI, I tracked a ~5W signal source on a 10" antenna in a 
building on HF roughly 45 miles across several valleys, two ranges of high 
hills and a lake, so even a relatively low powered signal blocked by most 
everything between a city and rural area you can image can get out when you 
least expect it.

One RFI book I have mentions anything within 30 miles as being a problem, 
another, anything within line of sight, which is pretty accurate.

Kurt