XPost: sci.electronics.design, sci.electronics.misc   
   From: kd1s.nospam@cox.nospam.net   
      
   In article ,   
   mike.terrell@earthlink.net says...   
   >   
   > upsidedown@downunder.com wrote:   
   > >   
   > > On Sun, 10 Mar 2013 02:43:08 +0000 (UTC), Cydrome Leader   
   > >  wrote:   
   > >   
   > > >>  Not many folks making hard coax runs anymore.   
   > > >   
   > > >this stuff was pretty darn old.   
   > > >   
   > > >are there power levels where they stil use wavegides and the like?   
   > >   
   > > In countries still using analog TV, the UHF final amplifier is often   
   > > implemented with klystron in the 100 kW range. The waveguide is quite   
   > > large, due to the low frequency.   
   > >   
   > > DVB-T digital TV transmitters typically operate with only 1-10 kW,   
   > > consisting of multiple redundant solid state modules, so there is not   
   > > much need for waveguides any more.   
   >   
   >   
   > How do you get that to the antenna without waveguide?  Coax losses are   
   > much higher than waveguide, and is less likely to have problems since   
   > there is no dielectric to break down.   
      
   Hardline! In essence it's a solid shield with a center conductor. That's   
   enogh for RF into the 900MHz and 1.2GHz range.   
      
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