Remember, the H fields DO NOT need to be exposed to elements... they will work fine in a basement or attic, or anywhere there is a quiet EM environment, and no magnetic walls or structure to interfer.
The E Probe to be best effective MUST be outside, no connection to ground... away from metal... height above ground seems to be important, at least a couple of meters, away from any buildings, noise, other structures, HVAC etc... it functions as a probe sensitive to charge content in air, and is very sensitive.
One of the best things a person can do with any of the Outdoor installs would be to disassemble periodically, and check for moisture, etc Like Dale, many of us have learned that lesson, especially with connecdtors... Folks in 'salty' environments face a real challenge..
If air can get in.. so can moisture. Nothing beats a bit of Preventive maintenance, since I cannot guarantee my ability construct a hermestically sealed enclosure... heh...