54fd67e9   
   From: lumpy@digitalcartography.com   
      
   miso@sushi.com wrote:   
   > SPLAT! has modes to predict radio signal strength. I'm just doing line   
   > of site for now, but the program can handle Fresnel (sp) zones and   
   > such. There are professional programs for such modeling.   
      
   Look, for example at the area east of Groom Lake,   
   between the dry lake and Tikaboo. The model shows   
   that as "dark" but I guarantee you'd have comms   
   from Tik to the floor of the valley there.   
      
   It's just really hard to predict what RF will do.   
   RF is even weirder than light. Especially around   
   rocks, the rocks act exactly like a waveguide   
   in a microwave transmission line. The voltage   
   and the current component of the wave are 90   
   degrees to each other. But once it starts bouncing   
   and refracting, those components change places,   
   enhance/cancel each other, evoke voodoo, all   
   kinds of weird schitski.   
      
   When we installed 800 systems in Arkansas,   
   we discovered that the average length of   
   the region's pine needles was nearly exactly   
   a quarter wave at the frequency. Singly and   
   in small groups, they acted like radar chaff.   
   But in thousands of acres of forest, they   
   acted like an elevated ground. That would   
   tend to pull the pattern toward the earth.   
   We'd hear mobiles from several hundred   
   miles away and we could actually communicate   
   both directions with them. Got really spooky   
   when "One-Oh-Nine" was 10-8 but we knew that   
   our "109" was doing something else.   
      
   We ended up scrapping the 800 system and   
   returning to high band VHF. We lost the   
   GE and MOTO radios that had been on and   
   functioning for decades. Had to go to   
   moto flood board (SMT) "disposable" radios.   
      
   Price, progress.   
      
      
   Lumpy   
      
   You were the Tidy Bowl Guy?   
   Yes. I'm cleaning your bathroom bowl.   
   www.LumpyMusic.com   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)