RF does not travel throught the power line...
RF is transmitted over the air. Distance is
extremely variable and is dependent on
antenna positioning and also the device doing
the sending....
While I can't provide specifics, RF reception
from a PalmPad is often between 20-50 feet.
I replaced the antenna with a home-built one
and get about 175 feet using plans from
ActiveX10.com.
RF transmission sucks on new units. I could
barely get 10-15 feet before ant mods. Can't
get any more as the antenna is a incoming mod
and not balanced for Tx performance.
Line-level ranges are often the same (20-50
feet) and are dependent on the noise on your
AC, power Tx from the CM15a, and other
factors. My 3000 sq-ft house can communicate
line-level commands everywhere except 1
outlet/circuit.
Unfortunately, both of these numbers are
highly variable.
Good Luck
Eric