On Jul 31, 10:53*am, "Vinny P." wrote:
I mounted an 802.11 WiFi antenna and was dismayed to find two drill bits
dulled (I don't think I've dulled more than that in my entire life) just
trying to drill an inch through stucco to mount an antenna.

There is 'something' as hard as a steel beam one inch under the stucco
near the roofline that just can't be drilled through.

What could possibly be there (in the wall?)?

The reason I ask is I have to replace the flimsy mounting arm with a
stronger one from a Dish TV installation - so I'm going to have the
problem again.

I'll choose a new location - but I don't have much choice within a few
feet given I need line of sight to the WISP access point.

What could it be that is hard as steel one inch below the stucco?

Probably a steel support of some kind.
Here's how I wold handle it. Find a cobalt drill bit the correct size
for tapped threads of the bolts you plan to use. Drill out the hole
and tap threads into the steel with proper techniques. Insert bolt and
tighten, and if there is sufficient material to act as a retaining
nut, go with that, adding other tapped holes as needed by the mount.
If the 'steel' is too flimsy, drill out for the bolt clearance
(cobalt, again) and use conventional bolt + nut.
Use care drilling if you are on a ladder.

Joe