Thanks all for the responses. Moisture would be most difficult to keep out.
Moisture in the form of condensation would be a greater problem for it than
the rain, snow, and ice it would be exposed to if it were above ground.
"Jerry" wrote in message ...
Is 450 ohm ladderline effective underground if enclosed in underground PVC
conduit? It would run from the outside of the shack underground to the
base
of the antenna, and then run exposed to the feed point of the antenna.

Thanks.

Jerry