Topband: Underground twisted pair

[Bruce]

Anyone on the reflector had experience burying unshielded twisted pair wires at HF frequencies?.  

How much loss?   Estimated ?  Measured? 

When burying, was there a before and after  common mode increase ?


Notes
At audio frequencies the phone companies used to run many twisted pair in lead shields.

In Radio stations, where I was employed, shielded twisted audio cables were used in high RF environments successfully.

Thanks in advance for replies.

73
Bruce-K1FZ
www.qsl.net/k1fz/bogantennanotes/index.html