Outdoor AP coverage??

[JustTakeTheFirstStep]

We plan to install the outdoor AP 9124E on the roof of a building with a height of 10 to 15 m.
The AP must cover the first floor ground level.

Can an outdoor AP send a wider signal than an indoor AP?

I've been looking for a lot of guides to use directional antennas, but
I don't know which gain antenna to use.

For example, how many meters can you cover for 10dbi gain?

Thanks a lot for your advice.

[Leo Laohoo]

Get someone to conduct a wireless AP placement or wireless site survey done properly.

[Scott Fella]

I don't think anyone can answer coverage questions here.  Like what @Leo Laohoo mentioned, a site survey will allow the engineer to try different antennas and ap's to determine what is possible.  When you mentioned the ground floor, I'm assuming you mean the outdoor area and not any indoor area.  Also keep in mind that access points are certificed for outdoor use.  Indoor access points are not certified to be used outdoor due to regulations.  So you need to determine that depending on where the ap will be located.