F325 has limited DL

I have a customer who’s been noticing that their download speeds have been very low lately. They are 1 of 7 customers on this AP (3k) and the only one that seems to be having issues. When I run Link test, if it doesn’t fail, it shows that the DL is around 5-6Mbps and the Upload is around 20-25Mbps. When I fisted install them over a year ago, it was pulling 112 down and 25 up. Any thoughts on what the issue could be? I ran the Specturm Analyzer and there is no major sources around it.

Downlink RSSI -60 dBm
Downlink SNR 28 dB
Uplink MCS DS MCS 9 - 256-QAM 5/6
Downlink MCS DS MCS 9 - 256-QAM 5/6


Interference near 300-25 :frowning:

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If it was RFI, wouldn’t it show up on the spectrum analyzer though?

The epmp3k spectrum analyzer is a pretty crude tool. We install mikrotik routers as our demarc and can always find interfering (local) radios pretty quickly with them by performing a quick scan on the 5Ghz wireless interface.

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99.99% of the time the customer’s wifi router has decided to run on the same/overlapping channel as your radio. Something you can try is to have the customer reboot their WiFi router while making sure they do not reboot your radio. Since most wifi routers do “auto channel selection” by default the idea here is that when the wifi router is booting back up it should see your F325 and it should pic a non-interfering channel. Doesn’t always work but usually it does.

You can try running the spectrum analyzer on the customer radio but it’s really frustratingly slow, prone to crashing and for the most part straight up don’t work… but sometimes it manages to show you the the problem.

Otherwise load up the Ubiquiti WiFi Man app on your phone, drive out to the customers house and probably be able to ID the interfering router without even getting out of your vehicle.

The customer’s router is a unit we manage so I know it is not near the channel we’re using for the link. I spoke with him this morning and he did mention they had an extender in the basement. I’ll stop out there and try Wifiman and see what comes up. Thanks

Well, the other .01% of the time it’s their printer (HP printers are horrible about his and making it very not straight forward to disable / turn it off) or TV (Vizeo TV’s can have a WiFi AP built in that can be a real pain / impossible to shut off) or Satellite/Cable TV wireless receivers can be terrible interferers.

Of course it could be a neighbor or another near location in the customer radios path. May not even be a WiFi source and since the SA in the radios is so worthless you don’t really have a way to figure that out short of using a 3rd party SA. It’s really frustrating that ePMP doesn’t have a working SA or even WiFi scan.

Might check what MCS rates are actually being used on customer radio Monitor > Performance > Downlink Packets Per MCS and look at what MCS rate most of the packets are being received at. If the radio is showing MCS 9 but the majority of transfer is happing lower MCS rates then noise / interference pretty likely the culprit. ( you may see a notable % at SS MCS 1 but that is normally control / management packets that only use MSC 0 or MCS 1)

Also might check the Chains on the customer radio, a big chain imbalance will show the RSSI of the good chain while the bad chain drags your transfer rates down. You can go to Tools > eAlign to see ch0 / ch1 RSSI.

Hi @tophfro,

could you post your Monitor >> Wireless and Monitor >> Performance pages from your AP and SM?

oooh, wifi extender bridges are the worst! These usually use both a 5ghz and a 2.4ghz channel and do not have the smarts to pick a non interfering channel.

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