[RFI] Power Line Ultrasound Detector

[W0UN -- John Brosnahan]

I have been thinking about adding to my arsenal of power line RFI
tools and the next one should probably be an ultrasonic detector with
a parabolic dish.

Obviously, commercial ones are too expensive, AND I don't get to
learn anything in the process, like I would if I build one.

Just wonder if anyone has any technical info on the commercial ones?
Or any info on a write-up on a homebrew unit?  I have spent some
time doing google searches to no avail, and I have not yet found a low
cost clear-plastic parabola -- any suggestions.  I realize I don't need
a clear-plastic dish for this -- just that it would make it look more like
the professional ones.

Just seems like a fun little project.

Thanks for any tips.

73  --John   W0UN