one simple answer is C/P from another forum Clear Line of Sight and Freznel Zone isn’t everything; It’s the only thing. Adapted quote from Vince Lombardi Why don't I just put that on the roof 5210 is...

http://www.tp-link.com/en/article/?faqid=357

How sensitive is this device to obstructions like trees? 1-do you have LOS (linea de vista) on your PTP (punto a punto) 2-Region Mexico, you mean DF or what city are trying this, urban environment...

i dont advice Bridge mode, 1-5210s will work at 50% of its capacity 2-you will have to use WEP security, do you really want to use WEP today I want to establish a bridge from building A to building B...

I experience the same problems with my internet connection as already indicated in another thread but I'm not able to solve it... which thread.

Read this post, interesting data for you http://forum.tp-link.com/showthread.php?72296-Throught-put-performance&region=china