Chief David:The H-field antennas, using rj45, DO NOT need to be outside!! Just away from noise sources....; basement, garage. attic... whatever.
Because of the type sensing used in the E field, it SHOULD be outside, at least a few feet above ground, and as far from ANY structures, vegetation, whatever. The air and earth are part of the probe structure...however some folks have hung them in the attic... but definitely not recommended. Now, Paul's RED system has three E field channels, so selecting one or more of them could make that 'indoor' attic install work better... but I wouldn't count on it. It connects with 75 Ohm coax, but it needs to be premium, at least double shielded, and pure copper.. You DO not need E field to be effective... the magnetic H field channels do fine by themselves.
So unless you want the most effective E field you DON'T need to run outside at all... with the caveats on eField in mind. As long as you can get shielded RJ45 to the H field antennas, and they and the controller are away from electrical / magnetic noise, you're good to GO...Need anything, pm me..
This is a great 'add on' for school kids, BTW.
Mike