Please i need. I need to establish a 70km Link with mikrotik. Can someone help me configuration of radios and antennas to use

You should have posted this in the wireless forum. You have alot of homework you need to do, but yes a 70km is possible. Two big 5ghz antennas with xr5's and a couple of mikrotik boards.

http://www.mikrotik.com/test_link.php