I think you should modify the settings of the router.
In Wireless Settings do these settings
Wireless Network Name:( Whatever you want to set)
Region:Bolivia(After testing change it to your original country)
Transmission Power:100%
Channel:Auto
Mode:11bgn mixed
Channel Width:40Mhz or Auto

Wireless Security
Select WPA/WPA2-Personal.
Version:WPA-PSK (Compatible with most devices)
Encryption:AES
Wireless Password: (Whatever you want)

Save all settings then tell if problem continues.

Thank you, but the settings you suggested are virtually identical to the initial settings, I only changed the region.
The signal drops substantially with distance. It is not a matter of the antenna, because if I change it with a longer one I still get the same drop.
Steve

Siddhant001 wrote

I think you should modify the settings of the router.
In Wireless Settings do these settings
Wireless Network Name:( Whatever you want to set)
Region:Bolivia(After testing change it to your original country)
Transmission Power:100%
Channel:Auto
Mode:11bgn mixed
Channel Width:40Mhz or Auto

Wireless Security
Select WPA/WPA2-Personal.
Version:WPA-PSK (Compatible with most devices)
Encryption:AES
Wireless Password: (Whatever you want)

Save all settings then tell if problem continues.

Which devices you are using to connect to WiFi.
I have also this type of problem and I then came to conclusion that it is because of the device you are connection to the router.
My problem is that I have two Mobiles on of the mobile connect to the AP successfully over distance but another just drop out signal or not giving download speed.
So tell which device is facing that problem.If you are facing the problem with all devices so please just use my setting as above mentioned as it help's.