Where I live there are many barns made exactly this way. Pressure
treated 4X4s 4' deep and a 3 bag mix seems to be the standard. Some of
these barns are huge and many have been up for many many years. Should
work just fine.
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
TowerTalk mailing list