RHF wrote:

snip

Extra Protection* for the Buried Coax Cable can be obtained
by using Half-Inch (1/2") Black Polyethylene Drip Water Tubing
{Hose} as an added Layer of Protection for Buried Coax Cable
against damage from Plants, Tree Roots and Animals.

I have coax running through 1 1/2" PVC buried at 2 feet but
be advised that you must provide a means of draining condensation
or include desiccants or provide dry air flow to avoid water
in your cables. In my case, I periodically blow out the pipe
with compressed air and also have a 1 inch per foot grade to
encourage drainage to one end where the water can then be
extracted (blown out).

Regards,

Michael