The following is still getting put together and is not yet edited. Excuse the text
Interesting vision of the future provided by Google
explains a good signal at the AP and the station showing less..
If you have large asymmetry between transmit and receive, this may imply either interference or obstructions in the path. Do an AirView scan to check for new interference on channels.
Channel width explained:
In 20mhz, using frequency 5600 would mean the frequency CENTER is at 5600mhz (1590 – 1610)
In 40mhz, a second sub channel is used (two 20mhz channels total), upper or lower refers to whether the channel is in the next slot up, or down in spectrum from the main channel.
for instance, in 5600mhz, 40mhz “upper” the main channel is centered at 5600, the sub channel is centered at 5620. in total you are broadcasting from 5590 – 5630 (40mhz)
UPPER and LOWER only applies to 40MHz instances
How can you test your radios for performance?
You need to set up a test range such that the predicted signal level arriving at the CPE is less than -50 dBm. Anything stronger than -50 dBm, like -40 dBm will start overloading the receiver and the AGC kicks in, and you’ll get flawed results.
You have three parameters to set:
- Reduce transmitter power output (TPO).Not all radios can be set down to or below 0 dBm.The Loco 2 can only go down to 0 Dbm.The Nanostation M2 can go down to -3 dBm and the Rocket can only go down to 6 dBm.
- Goal of received end-point signal level less than -50 dBm. -50 down to -70 would be acceptable.-50 up to -20 would not be acceptable
- Use distance attenuation to get that -50 to -70 dBm signal level.This may have to be as much as 200 feet for the higher gain NanoBridges.
Choose a distance in feet for the appropriate free space loss:
Free space loss for 2.4 GHz:
400 feet = 81.8 dB
200 feet = 75.8 dB
100 feet = 69.7 dB
50 feet = 63.7 dB
Free space loss for 5.8 GHz:
400 feet = 89.8 dB
200 feet = 83.4 dB
100 feet = 77.3 dB
50 feet = 71.3 dB
Free space loss for 900 MHz:
400 feet = 73.2 dB
200 feet = 67.2 dB
100 feet = 61.1 dB
50 feet = 55.1 dB
TPO + internal antenna – RF path loss + internal antenna gain = Received signal at receiver
Example with Nanostation M5:
Nano M5 + internal antenna – RF path loss + internal antenna gain = Received signal at receiver
-3 dBm + 14.6 (VPOL dBi – 77.3 dB (loss at 100 feet) + 14.6 dB (VPOL) = -51.1 dBm
If you get significantly less than -52 dBm, say -62 then you have a weak receiver.
Lightning strikes causing radio damage.
Using Ubiquiti shielded tough-cable and shielded RJ45s will greatly reduce (maybe eliminate?) the likelihood of this problem occurring, because the radio will be grounded (provided the outlet the POE is connected to has a good ground).
Some helpful information
Restore routers to factory default values
After setting up your router make sure you return your laptop/pc to a configuration in which it obtains its configuration automatically – auto DHCP (also described, at the end of the video)
Antenna gain and cable loss
Ubiquiti makes several antennas:
5 GHz MIMO antennas:
120 degree sector 19 dB gain
90 degree sector 20 dB gain
120 degree sector 16 dB gain (small)
90 degree sector 17 dB gain (small)
Omni 13 dB gain (large)
Omni 10 dB gain (small)
24″ Dish 30 dB gain
40″ Dish 34 dB gain
2 GHz MIMO antennas:
120 degree sector 16 dB gain
90 degree sector 17 dB gain
Omni 13 dB gain (large)
Omni 10 dB gain (small)
24″ Dish 24 dB gain
120 degree sector 18 dB gain
24″ Dish 26 dB gain
120 degree sector 13 dB gain
Ubiquiti has spec sheets (PDFs) on there web site for all their products!
Antenna gain and cable loss are used only to calculate the EIRP when the ‘obey regulatory regulations’ is checked. Otherwise they are ignored completely by the radio.
Because most Ubiquiti radios use internal antennas, there is no cable loss. If you use a Rocket with AirMax antenna, there is a very short jumper cable; add 1dB for that.
If you use Bullet radios, you should always attach it directly to the antenna if possible. If not, add a small amount for the short jumper. For example, a built-in jumper on a grid antenna might add 1 or 2dB. Don’t use long cables.
Also connector loss. So add an extra dB to each item; for the short AirMax jumpers perhaps total 2dB and for an antenna jumper perhaps 2 to 3dB.
Those values for cable/connector losses and antenna gain are only for the rf cables and connectors between radio and antenna, and for the internal or external antenn and rf cables are to be avoided when possible!
CAT5 [network] cable has no rf losses, and its length is not a factor.
The figures for gain and loss are for antenna gain and loss from the rf coax cable and its connectors between the radio and any external antenna.
Naturally, if there is no external antenna, there is only the internal anternna gain, and there is no rf coax cable loss because there isn’t any cable and there are no connectors.
CAT5 cable has no rf loss because it carries no rf; its length is not entered into the loss field in the radio setup. Its total length–the sum of the length between the radio and its PoE supply and between the PoE supply and the end device
(PC or switch) must be no more than 100m.
From a installers mouth… Needs editing!
The majority of our current issues with speed relate to the negotiation of the Ethernet port. Sometimes its the cable, sometimes its the brand of the device connecting to the ubnt, but all cases are FIXED by changing the ubiquity Ethernet port to half/full or vice-versa. Our latest problem was that actual speed would not break 1Mbps on “auto” but with 10-half, real speeds reached 5-10Mbp
It may be useful in some circumstances (for example if I have a faulty cable). Once in the past I do it when I had some errors on a Pico 2 that was connected with a long cable… and the cable was damaged. I put the switchport at 10/auto and it worked magically. It negotiated 10mbit full duplex and was OK.
AP-WDS 40 MHz, some Stations WDS connected to it with good signal level, but some with bad. All staions in 20/40 auto mode. Can I manually setup for example 20 Mhz on one station with bad signal and it will connect on 20 MHz to AP with 40 MHz bandwith
NO both have to be the same, for P2P.. and not 40 MHz as most devices won’t connect
POWER CYCLE YOUR ROUTER
Faulty radio, initiate a RMA: http://www.ubnt.com/support
Unifi uses a Hard Handover for client roaming. This means the session will be disrupted however breifly.