Jim,
I have used the search option, but no matter what I type in nothing on the Shepard pole installation for footing requirements comes up. I have and read the requirements for the six foot banjo sign and poke which I hope will be compatible with the hexagon sign that I will follow. Somewhere here on oldgas it said that the Shepard pole stood only 10 ft. high. Is this the reason for not much of a footing? Just that it is below the frost line? Also to me it seems that the Shepard pole stood higher than 10ft. in the pictures I have seen, or it's just my imagination at play.