For RF, line-of-sight often isn't enough, one needs to worry about the Fresnel zone as well: http://www.zytrax.com/tech/wireless/fresnel.htm http://www.zytrax.c

For RF, line-of-sight often isn't enough, one needs to worry about the Fresnel zone as well: http://www.zytrax.com/tech/wireless/fresnel.htm http://www.zytrax.com/tech/wireless/fresnel.htm Links will work until something changes in the zone (trees grow, get wet, &c), then it might get unreliable.