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November 17, 2018

Unifi AC Mesh wireless uplink

So in order to smoke my cigars and pipe tobacco during the winter, I have to head to the garage which is not attached to the house. The problem is the house has aluminum siding, which is great for longevity and low maintenance, but reduces my phone's ability to grab a solid signal from my Unifi AC Lite from inside my house (see original post). My ThinkPad can get a decent signal since the laptop's wireless card is stronger than the Essential PH-1. (This phone has 10 dBm worse signal than the OnePlus 3T! Must be something with the ceramic backing and the antenna bands, who knows.) Anyways, most of the time it's unusable, and for some reason the colder it gets, the worse or nonexistent the signal (-80 or 90 dBm). Enter the Unifi AC Mesh. Rated for outdoor precipitation, and most importantly for my application, temp rating of -22F. 

Cable just for PoE, not data

The install was typical Unifi smoothness:
  • Plugged into my Unifi switch
  • Adopted
  • Provisioned
  • Upgraded
  • Enabled wireless uplink
  • Set the 5 Ghz channel to 36 on the Mesh AP. My theory would be the lower the frequency for the wireless 5Ghz backhaul the better for distance and penetration of the aluminum siding.
  • Set the 5 Ghz channel to Auto on the Lite AP, since I want the clients in the house to be able to go to another channel besides 36 so as not to interfere with the wireless downlink to the Mesh. 
Very happy with the result AFTER learning that my channel theory didn't work for two reasons:
  1. The Garage WAP (manually set to channel 36) saw that the House WAP was using channel 46 (since I set the house to auto and it determined that was the least crowded) and ignored my manual setting. (see below screenshot's small red triangle warning) This must mean the radios in the House WAP can't serve two separate channels. Guess common sense would have told me that, but it was a cool theory to test and also cool to see that Unifi's firmware is smart enough to ignore an incorrect channel selection in order to maintain it's uplink. Good stuff
  2. After realizing this, I decided to further test the theory by seeing the difference between a lower and higher 5 Ghz channel. See below screenshots. First is 36, second is 44. The 44 actually had a slightly better signal, probably due to interference from other neighborhood WAPs on channel 36. But the Tx and Rx were different. So conclusion would be that it is evident the surrounding RF environment has far more effect that just differences in frequency alone.
36 channel

44 channel














See channel warning in bottom right of screenshot

Something else I did was reduce the 2 Ghz power on both WAPs and increase the 5 Ghz. The reason is that I prefer to stay on the 5Ghz as much possible for bandwidth when transfering/streaming files from my NAS, and since I don't need long range to the garage now that I have two WAPs giving coverage. The house WAP I reduced to low since most of the coverage inside the house is adequate with 5 Ghz, and the garage WAP I dropped to medium since I want some coverage in the drive way and yard where the 5 Ghz doesn't reach.

Anyways, working great after fine tuning. Got to love the price, simplicity and performance of Unifi.

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