Hi all: On one hand, I don't think this is PBO, then on the other hand, I don't have any idea WHAT is really is.. IF !! It's PBO; then there are some serious Oscillator issues going on.. It's anybodys guess..: http://dl.dropbox.com/u/49203948/UNID%20Signal%20on%20187205%20KHz.jpg 73: Andy - KU4XR