I've never done this before so I merely ask advice.

Googling, I find that this seems to be the set of steps to install a
combination TV WiFi (WISP) antenna pole (mast?) in the San Francisco bay
area San Franciscian sediments (mostly chert) where it rarely freezes for
more than a couple of hours but the wind can easily top 100 mph.

I'd like it to be removable (not sure why ... but it just seems like
that's a better way to do it than installing it permanently).

Critique requested on the initial plan:

1. Go to Home Depot and buy large thick steel pipe for the support, maybe
two or three feet long (1.5" ID?); also buy a 15 or 20 foot long steel
pipe (1" OD?) for the mast.
2. Drill & tap a series of set-bolt holes in the top 6 inches of the
large pipe
3. Dig a two-foot deep hole in the soil, about a foot in diameter.
4. Fill the bottom of the hole to the 18 inch deep mark with gravel.
5. Mix concrete and pour the concrete around the large pipe to ground
level with the large pipe sticking up at least six or so inches
6. When set, lower a 15 or 20 foot one-inch OD steel pipe into the larger
pipe, and tighten the set bolts.

Anyone have experience in this type of endeavor that I may learn from
before I do this job?