Earlier this week, I shared how I was struggling to connect two Ubiquiti Lite AP 120 antennas. After two more days of attempts, I’m still facing the same issue between my office and home, which are about 350 meters apart.
At one point, I dismounted the unit from the tower at my home and tested both Lite APs just a meter apart — they connected successfully. I then tried again with one on my office balcony and the other on my home rooftop, but the connection failed. To troubleshoot further, I brought the office Lite AP home and tested at different distances ranging from 1 meter up to about 14 meters. In these cases, they connected without issue.
This made me think the problem could be related either to distance or line of sight. But I find this confusing, because when one unit was on the office tower, there should have been clear line of sight.
I also tried a small experiment at home: placing one Lite AP outside on the rooftop and the other inside a room, with the only line of sight being through the doorway. In this setup, they couldn’t communicate. This made me realize the issue might be related to the Fresnel zone - even if you technically have line of sight, any obstruction within the Fresnel zone can block communication. The following video shows the small experiment.
For comparison, here are some wireless coverage figures:
* TP-Link WL841N: \~45m indoors, \~90m outdoors (clear of obstructions)
* TP-Link EAP225: \~300m outdoors (clear of obstructions)
* TP-Link CPE510: up to 15km for point-to-point links
