Can you post a draft of your campsite with the network topology?

And what is the model of the exitsting AP? TL-WA7510N is a 5GHz directional AP so it may not fit your requirements.

The router and the two existing repeaters were not installed by me, so im not familiar with this hardware.
The router is a routerboard rb433, the repeaters are routerboard rb411AR with r52 boards installed.
I think (have to check that) 2,4Ghz is used, the r52 board can do both frequencies.
http://routerboard.com/R52

The arrow in the picture points to the new powerbox, where I plan to install a new repeater.

The wifi is open, there is no kind of security or encryption. The guests on the campsite get a passwort,
which they have to enter at a landingpage, after they connected to the wifi.

Thank you for your help!

Werner

Another question: What is the area you need the repeater3 to cover?

The location_3 is only 50 meters away from the central router. So distance won't be a problem. But as there are already two repeaters exit, adding a third repeater may not achieve good performance because repeating wireless signal will cut off the efficiency by 50%.

Yet I think you can try CPE210 for your case rather than TL-WA7510N. My suggestion is:
1. Buy a CPE210, don't buy an omni antenna first. Run quick setup to configure repeater mode or bridge mode. Remember tick the option "lock to AP". If it works and meets your requirement, it is done.
If you find that the signal angle is too narrow to coverage your target area. Go to next step.

2. Buy another CPE210 and connect it to the CPE210 through wire. The second CPE is used to face another direction. I think two CPE210 is enough for such a small area as long as you place them at suitable location/height/direction.

Note: CPE210 cannot add any external antenna. So if you do want to use a AP + Omni antenna. You can choose TL-WA7210N + 2.4G omni antenna. But TL-WA7210N can't handle as many client as CPE210 does.

Thank you for your help Tobacco! :)

I need to cover the space west and south of the new position. So one or two of the CPE210 would do the trick.

Watching the picture of the campsite, I think I saw an ever better solution:
I move repeater 1 to the new powerboxlocation. That should cover most of the area,
and I dont loose performance by installing another repeater!

If this wont work, I will do as you suggested.

Thanks alot!

Werner