XPost: sci.electronics.basics, sci.electronics.repair, sci.electronics.design   
   From: phil_a@tpg.com.au   
      
   "Bob E."   
   >   
   > PS, a police helicopter just flew over the neighborhood at a few hundred   
   > feet. The digital channel I was watching blanked out completely. This at   
   > about 50 miles from the broadcast site, as the crow files (Sutro Tower).   
      
      
   ** Low flying aircraft tend to do that  ...   
      
   Just like a nearby metal structure causing "ghost" images, they produce   
   strong reflections of the transmitted signal so your antenna gets two   
   similar strength signals, one of them delayed by a few microseconds.   
      
   This is often enough to seriously corrupt the wanted signal so large amounts   
   of data are lost.   
      
   End result, the pic freezes or pixellates crazily.   
      
   Bad luck if you live near a major airport and rely on an off air signal.   
      
      
   ...  Phil   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)