Sea, > So, my only guess is that the radar is > seeing an echo from all the mercury (?) ions being jostled around inside > the light at 60 or 120Hz. I'm not surprised that I would be able to detect > such an echo, only surprised that it is SO strong, it is much stronger, for > example, than the echo from my power supply fan. > > Any ideas? Inside the Fluoro' tube is a column or ionised gas which is thrashing around like an angry snake, as well as being formed and extinguished at a 100 Hz rate. By definition, it is heavily ironised/conductive and thus reflects radio waves exceedingly well... I guess your experiment is similar to the ham radio operators who bounce signals off the Aurora. They hear very strong signal which are heavily modulated and distorted by the rapid movements of the Aurora ............................ Zim -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.