I bet this is the daftest question posted in here for a while!

I need to set a 4 inch square, 2 metre high, metal post into the ground.
The ground is soil. The post will have a switch mounted on the side at the
top, and as such the post will be subjected to daily stress from people
pushing the switch.

The post has been put into the ground by someone in the past, with very
little cement. I think the combination of insufficent cement and lack of
depth into the soil has caused the post to become loose. I am thinking of
using concrete this time, but I have no idea how to make it.

What are the proportions for sand, cement and ballast.

All help appreciated.

Jon