Shoddy performance from UniFi nanoHD APs

[CntrlAltDel]

Sup peeps,

I’m troubleshooting inconsistent throughput on two UniFi nanoHD access points.

Setup

• UniFi UCG-Max (UniFi Network Appliance - 10.0.162)
• 2x UniFi nanoHD ceiling mounted 3.5m high (Over GbE CAT5E cable runs no more than 15m directly to UCG-Max with UniFi Gigabit PoE AF injectors)
• 5 GHz only, 80 MHz channel width (160 MHz is worse, I've even tried 20 and 40MHz, at 20MHz I get less than 50Mbps also inconsistently)
• Non-DFS channels
• Each AP on a separate channel, and the channels appear unused in my area

Symptoms

• Throughput varies heavily: ~50 Mbps to ~200 Mbps (Do want to make it clear that 200Mbps is fine, my issue is more that it behaves so inconsistently jumping around, on 2.4GHz my throughput goes to even below 1Mbps with jumps to 5Mbps and then all of sudden 50Mbps, something is off here)
• Reproducible on both APs, same behaviour
• Testing done standing directly under the AP
• Around 6 m away in the next room, RSSI is about -82 dBm and fluctuates, matching the throughput swings
• Clients roam/bounce between APs frequently despite good physical placement

What I tried

• Adjusting TX power (lower/higher across presets): no change
• Checked cabling/termination to APs: link appears healthy, nothing obvious
• Change channel width to 20/40/80/160MHz, lower channel widths just result in even lower throughput but equally as inconsistent.

Spoiler: Stats from right underneath the AP

Spoiler: Stats from less than 6m away through 1 wall

I also wondered if my Ethernet cable runs/terminations to the APs are the issue, but everything looks normal and links show as healthy.

 

[degrub]

i'm looking at this from a hardware perspective. Don't know the Ubiquity software.
North America based or EU or ?
How long have these been installed ?

Are these the only two APs you have ?

BTW, the two pictures labeled with spoiler alert are not showing the image.

in the OP, first you stated 5 GHz only (presume 2.4 GHz radio off) and then mention 2.4GHz results in the next section. Are both radios on ?

Are there other APs in the area that you see that have >-75 dB power on either band ?
What the power that each of your APs sees from the other ?

Did you use the Ubiquity coverage predictor heat map utility for initial layout ?

What client are you using for testing ? phone, laptop, tablet ?
How are you testing ?
ideally use something like iperf to test local throughput - client to a hardwired LAN PC and reverse. Don't depend on "speed tests" across the internet.

Are you using included power injectors or purchased separately ?

Just to confirm the cables and power delivery, take one of the APs if possible, and connect with known good/different cat5e cables (both from the switch to injector and from injector to AP) and a TP-link or other Af or stronger rated injector (48V, >0.3 A). Set the AP on a horizontal surface. Same results with local bandwidth tests ?

 

[CntrlAltDel]

i'm looking at this from a hardware perspective. Don't know the Ubiquity software.
North America based or EU or ?
How long have these been installed ?

Region is ZA, and I've had these two for less than a year.

Are these the only two APs you have ?

Yes, these are the only two APs I have.

BTW, the two pictures labeled with spoiler alert are not showing the image.

They're hosted directly through SNBForums, maybe Ctrl+Shift+R hard refresh the page?

in the OP, first you stated 5 GHz only (presume 2.4 GHz radio off) and then mention 2.4GHz results in the next section. Are both radios on ?

I've tested every scenario. I mentioned 2.4GHz because even it is behaving weirdly. But I've tested with 2.4GHz on/off behaviour is identical. Even 2.4GHz performance is terrible only fairly uncongested channels.

Are there other APs in the area that you see that have >-75 dB power on either band ?
What the power that each of your APs sees from the other ?

They're not running in wireless mesh so I dont think I can see what the signal strength is of my other AP. But I'm not sure, I'm checking Radio/Environment log and I dont see the other AP.

Did you use the Ubiquity coverage predictor heat map utility for initial layout ?

No, it was eyeballing from my end, the rough distance that each AP has to cover is just 5m, technically I shouldve been able to install one dead centre of my home and it should reach both ends of the house just fine.

What client are you using for testing ? phone, laptop, tablet ?
How are you testing ?
ideally use something like iperf to test local throughput - client to a hardwired LAN PC and reverse. Don't depend on "speed tests" across the internet.

I'm using WiFi Man, just because it allows for throughput testing separated from WAN internet speed tests.

Are you using included power injectors or purchased separately ?

The injectors I use are UniFi PoE-48-24W-G-WH which come with the APs.

Just to confirm the cables and power delivery, take one of the APs if possible, and connect with known good/different cat5e cables (both from the switch to injector and from injector to AP) and a TP-link or other Af or stronger rated injector (48V, >0.3 A). Set the AP on a horizontal surface. Same results with local bandwidth tests ?

Brilliant idea I didn't think of. I just did this test now, I used my known good UGreen CAT6 cables that I've done 1Gbps on before. And I even removed the AP from the ceiling and kept it right beside me, the issue is identical, jumpy throughput, it went up by 50Mbps more and the signal was about 15dB better. Ultimately the issue still persisted.

And here's a quick snapshot of what happened when I walked 5m away into another room.

 

[degrub]

Has this issue existed from day 1 ?
i think you mentioned you have had these for less than a year ?

That looks like very weak signal level if the client was still attached to AP2-Backdoor. What did the signal strength plot look like for the same walk ?
Low bit rate is not surprising at those low RF power levels.

Does the same issue occur if you turn off one of the APs ?

Just curious, with what are your walls constructed ?
Concrete based or plaster lathe based walls will absorb a lot of signal power. 2.4 GHz may not penetrate well and 5 GHz is unlikely to.

Is this a single family home separated from others ?

Use of the design tool with a plan view of the building and information on wall construction can be very useful for determining likely layout issues. Radiation power plots are based on open air and RF isolated environment.

http://dl.ui.com/datasheets/unifi/UniFi_nanoHD_AP_DS.pdf

 

[CntrlAltDel]

Has this issue existed from day 1 ?
i think you mentioned you have had these for less than a year ?

Yep since day one. I never really needed the throughput but now that I have a block of free time in the holiday I kind of want to figure out what's going on here.
Honestly I just think maybe I should just get the UniFi U6 Pro as replacements since these nanoHD APs are meant for high density deployments hence the "HD".

That looks like very weak signal level if the client was still attached to AP2-Backdoor. What did the signal strength plot look like for the same walk ?
Low bit rate is not surprising at those low RF power levels.

In this case it roamed from Lounge to Backdoor. Regarding the RF power, this is set to 100% during this test.

Does the same issue occur if you turn off one of the APs ?

Yes, with absolutely no difference whatsoever. Issue persists.

Just curious, with what are your walls constructed ?
Concrete based or plaster lathe based walls will absorb a lot of signal power. 2.4 GHz may not penetrate well and 5 GHz is unlikely to.
Is this a single family home separated from others ?

Double skin clay firebrick walls. Another point to note, I had an ASUS RT-AC88U prior to my UniFi setup and I was able to (with the same distance) get around 550Mbps throughput.

Use of the design tool with a plan view of the building and information on wall construction can be very useful for determining likely layout issues. Radiation power plots are based on open air and RF isolated environment.

http://dl.ui.com/datasheets/unifi/UniFi_nanoHD_AP_DS.pdf

Based on the behaviour of my previous ASUS RT-AC88U I really doubt it's layout related, especially since I had the AP quite literally in my hand earlier and was getting choppy throughput between 150-300Mbps.

 

[degrub]

Yep since day one. I never really needed the throughput but now that I have a block of free time in the holiday I kind of want to figure out what's going on here.
Honestly I just think maybe I should just get the UniFi U6 Pro as replacements since these nanoHD APs are meant for high density deployments hence the "HD".

Most of the SMB APs are that way. High number of client devices per AP, 200 in this case. RF heat map would place each AP so that they overlap on the yellow area at around -65 to -70 dB as a starting point. Doubt there is much difference on coverage distance per say as the power is limited by regulation, but going from AC to AX may get marginal connections improved. Perhaps higher bandwidth as well, unless the client is the limiting factor. If you are working mainly from phones, then maybe not, depending on the generation as those are many times 2x2 radios at best.

In this case it roamed from Lounge to Backdoor. Regarding the RF power, this is set to 100% during this test.

i was asking for the plot of RF power versus distance, the other tab on the bandwidth display if that is what it is. Otherwise, RSSI value versus distance measured by the client device. The other thing that can be happening is the client device radio is not as strong as the AP radio and that is the limiting factor. It may hear the AP and attempt to connect, but cannot successfully , or only at low bandwidth communicate with the AP.

Yes, with absolutely no difference whatsoever. Issue persists.


Double skin clay firebrick walls. Another point to note, I had an ASUS RT-AC88U prior to my UniFi setup and I was able to (with the same distance) get around 550Mbps throughput.

Ugh, those will absorb plenty of RF power. Interior walls as well ?

Based on the behaviour of my previous ASUS RT-AC88U I really doubt it's layout related, especially since I had the AP quite literally in my hand earlier and was getting choppy throughput between 150-300Mbps.

Consumer level APs blast out at max legal power trying to reach as much as possible. . SMB gear is designed for more APs to give consistent coverage at adequate bandwidth. When i switched, i went from 2 Linksys units to 4 Cisco AC APs and got better coverage and roaming. My walls are thin gypsum board though. If you have interior walls with that brick, you would almost need 1 AP per room unless you have large openings.

1 - 2 meters is around the intended closest distance to the AP radio.

If the RF power (RSSI) is going up and down with the client at a fixed location, then either there is interference from another RF source or something is wrong in the radio. i would pay attention to RSSI first and bandwidth second for troubleshooting. Bandwidth is the result of AP RSSI and client RSSI so there could be issues either side.

It is possible you have defective units.

i was suspicious of the POE injectors at first, but with 24 watts available , power should not be an issue. AP radios are sensitive to inadequate power delivery. i would still want to try a third party injector POE+ so there is no question of power. You likely removed the cable issue with the earlier test.

Did you post on the Ubiquity forums or open a support ticket with them to discuss the issue ? They are usually decent and the forums supportive.

 

[Tech9]

In Settings menu, System, General select Professional Installer. The Radio menu will show you actual AP power in dBm.

In Radio menu, Channel AI will scan the environment and suggest the channels with higher available channel bandwidth.

Your client on the screenshot above is connected with 866/866 link speeds. If the channel is relatively clear this translates to >500Mbps throughput. I'm using everywhere on my UniFi networks similar hardware configuration 2/4-stream 2.4/5GHz APs (U6 Mesh) with the same 23/26dBm maximum power levels and similar gain antennas. Throughput >500Mbps isn't an issue and my APs are at 20dBm power on 5GHz band.

Test with more than one client for more consistent results. Good luck and Happy New Year!

 

[degrub]

Now that i can see the original screen captures, those look within reason. Your units are likely ok.

Can you pick up neighbor's AP radios by SSID ? What are the RSSI values/ Channels reported ?

i would suspect that it is the physical environment the radios are operating in - both the house and neighbor interference.

Follow Tech9's guidance above