I have bought a NetMetal ax to build an outdoor WiFi AP intended to cover a large area.
I also bought these two 2.4/5GHz omni antennas and five-meter cables to connect them to the AP with:
https://alfa-network.eu/antennas/wi-fi- ... 458-59-tfl
Only now that I already have all this stuff I started to look into the theory of how to actually set this all up, and I have some questions
1) My original plan was to have the antennas at the opposite corners of a 10-meter wide wall of a shed that is centrally located on the property, with the NetMetal at the middle. I wasn't clear on what "dual chain" meant so I thought the NetMetal ax had two independent radios that both did 2.4/5GHz. Now I realize that it doesn't, and that "dual chain" refers to 2x2 MIMO, so I'm having doubts. Are these antennas going to be too far apart for MIMO? I'm focusing on coverage, not bandwidth, so does that matter? Does this effectively degrade to a SISO setup with clients communicating with the closest antenna only?
2) Is the five meters of coax going to be an issue, coverage-wise? I also have two HGO-antenna-OUTs I could use directly on the NetMetal, but another reason I didn't want the screw-on antennas was to place the NetMetal inside, rather than outside, the shed for easier access.
3) What would you do?
The NetMetal ax is dual band and dual chain. It will do both 2.4 and 5GHz at the same time (dual band), and will use two antennas at the same time (dual chain) for both bands. Theoretically "chain" is a full radio but, in mikrotik-speak it just means front end.
I never put two antennas (of the same AP) that far apart. I'm sure MIMO is going to work for clients that are perpendicular to the axis between the two antennas (same distance to both antennas), but I doubt it's going to work if a client is 1 meter from one antenna and 10 meters from the other. Although I think it would work if a client is far enough, for example 60 meters from one antenna and 70 meters from the other, so that attenuation between the two antennas is small. The closer the client is, the higher the power difference between the two antennas will be. MIMO does degrade to SISO.
Five meters of coax is not an issue, although it depends on the coax. It has to be of the right impedance (50 ohm) and low loss for both 2.4 and 5 GHz.
Since you already bought everything, I'd say try it out and see what happens.
On a side note, putting antennas so far apart (of the same AP) opens up quite a legal conundrum. It's generally required to set TX power 3 dB lower if using two antennas instead of one, but what happens if the antennas are very far apart? What if they are 10 meters, 50 meters or 100 meters apart? What happens if I put two APs just a few centimeters from each other and on the same channel? Am I not required to reduce power? What if I put 10 APs all a few centimeters from each other and put them all on the same channel? Would that be legal? These questions are going to become interesting with WiFi 7 because the tech allows for a client to talk to multiple APs at the same time.
