I agrre with Frank about the coax "choke" cables. Given a little time they get harder and harder to work.
Take a look at this fascinating article about power transmission systems that often pumped oil wells as much as a MILE away from the steam engine that powered them.
http://www.lowtechmagazine.com/2013/...e-systems.html
I just learned that I'm not allowed to post the link because I haven't been real active here lately. It's in "lowtech magazine" under "the-mechanical-transmission-of-power-jerker-line-systems"
We probably could use some of the same concepts to operate the sliding openings in a grill block.