Remote Troubleshooting on Wifi with iOS Airport

Some days ago I helped my son when he complained about slow wifi in his rented apartment in Lisboa. To do this we used iOS app Airport to visualize the network.

I thought this process could be documented in a blog

The scenario is:

  • My son and a friend has moved from Norway to Lisboa in Portugal, into a rented apartment, for a two years study
  • It is wifi in the apartment
  • They have limited technical knowledge and they don’t know anything about wifi and which ISP there is in the apartment
  • I know it is a apartment built with concrete and with lot of corners,  and their bed/study rooms was on the other side relative to the living room and the ISP´s wireless router
  • He sent me a message complaining about slow wifi and some times where kicked off the network, and asking me what to do
  • In the living room is the ISP´s wireless router and in the hallway there is a TP Link device I assumed was a repeater. It was coax cabel into the ISP wireless router.
  • Vasco Costa, a CWNE, at Twitter as @VascoFCosta, is living in Lisboa and he gave me some valuable local insights and information during this process

They had Windows clients and iPhones, so I choosed to let him do some measurements with the free iOS app Airport.


How to install and use Airport

  • Install Airport from AppStore. It is free of charge.
  • When installed, go into Settings and find the app Airport. Turn on “WiFi search”.
  • Then turn on Airport and push “WIFi Search” and then “Search”
  • Let it search for WiFi network for approx. 30s
  • Push “Stop”
  • Choose the share icon and send the content to whatever you want.

First view
I asked him to do an Airport measure in his bedroom and send it via email. When I opened the mail I see a list consisting a lot of lines. In this blog article I have deleted all lines except one for each BSSID I see. This is an edited view.

This is a view of all the WiFi network the iPhone can hear/listen and the data we see is the SSID, BSSID, RSSI, channel and the clock for each network/BSSID when the measures is done. We see:

  • Only 2,4Ghz
  • Channel plan 1, 4 and 9 for all networks.
  • Several different BSSIDs using the same channels
  • Their SSID is “ZON-8A40”. We see a BSSID for their SSID with RSSI of -82dBm (from the living room)  and another BSSID with RSSI of -44dBm (from the TP Link repeater in the hallway).
  • Their SSID are alone at channel 9, but for how long?
  • A throughput test showed 9mbs downlink
  • Repeater system at 2,4GHz is not good enough for their study situation

Upgrading to a 5GHz Mesh System
Vasco sent me information on what a local retail store sells and a TP Link Deco 4 Mesh system with two units looked favourable. So he bought this and set it up. The main unit connected with catx cabel to one of the  LAN ports on the ISP´s wireless router and the other unit at the same place as the TP Link repeater.

The next Airport measure was this, from the bedroom. Now, I have removed all the other networks so we see only the Mesh units.

We can see three BSSIDs. Those two at 2,4GHz is the ones in the living room (-88dBm) and the one in the hallway (-55dBm), using channel 9. It uses the same channel as the existing WiFi network, but it is nothing we care about. We will use 5GHz.
The one at channel 36 in the 5GHz band with RSSI of -59dBm is the one in the hallway. An interesting point here is the lack of the BSSID at 5GHz from the unit in the living room.
The throughput test gave us 66 mbs downlink and 6 mbs uplink, so I was pretty sure they was associated to the 5GHz band even the mesh system used the same SSID on both band.

Since we don’t see the main unit from the living room at 5GHz we could have several challenges, but my main concern was the link between the main unit in the living room and the mesh-unit in the hall way. So the next test was to measure the RSSIs by the hallway mesh-AP


First measure near the hallway mesh AP

He placed himself near the hallway mesh-AP. This measures could probably been better and more accurate, but its is good enough for us.

It looked like this, only our 5GHz BSSIDs

As we see, the RSSI from the living room AP, by the hallway AP, its down at -81dBm.
So the hallway AP receive frames frames the main unit in the living room at a level at approx -81dBm, while the RSSI from the hallway AP in the bedroom is at -55dBm.
-81dBm is way below what we want for received RSSI in a WiFi system
So a good solution could be to move the hallway AP nearer to the main AP. The RSSI in the bedroom will go down, but we have a good margin (down from -55dBm).

Adjusting the placement of the hallway Mesh-AP

So he did. I don’t know where he moved it, but the next Airport measures from the new place for the hallway mesh-AP gave a much better RSSI from the main AP in the living room.

I have edited together measures from the hallway and from the bedrom. At the hallway mesh-AP the RSSI from the living room is -70dBm (raised from -81dBm) and into the bedroom the RSSI from the hallway AP is -67dBm (got down from -55dBm). So the RSSI is pretty well equaled between the units in this network.

And the throughput test went up to 100mbs, at least downlink. When I get a throughput test at 100mbs in a mesh system and without any knowledge of the ISP´s data speeds, I am satisfied.
And, most important, the boys was satisfied.  And the father became EUR99 poorer, but I helped them to get a good opportunity to study from home when they must do that


Airport comments

I used Airport in this case and the app is suitable for these kind of situation where I am remote and the locals have little or no technical knowledge.
I could have imported the Airport data into WiFi Explorer and get a visualisation, but I didn’t have my MacBook available.

It is some data which are not available by using this method. Those are among

  • The bandwidth for the channels used in the 5GHz band. Airport reports only 20MHz channels
  • Which BSSID the device is associated to when we uses iPhones, and iPADs. This is a general problem on iOS devices.

But we can assume the iPhone is associated to the correct BSSID since the throughput is approx 100mbs. It is only possible by using 80MHz (or 40MHz) channels in a mesh system. A 2,4GHz association would have given throughput below 50mbs.


If we had used AirPort imports into WiFi Explorer

It is possible to import the lines from Airport into WiFi Explorer. Just copy all the lines in Airport and paste it into WiFi Explorer.
The first measure would look like this:

Only 2,4GHz, channel overlap and channel interference. Our old network used channel 9.

After upgrading to a 5GHz capable mesh network looked like this from the bedroom:

It is many network on our SSID at channel 9, but we don’t care about it because we don’t use it. At 5GHz it looks like the mesh system uses channel 36 and 20MHz, but we know there is a 80MHz channel because the Mesh units are 802.11ac capable.



I have used the free app Airport from AppStore for iOS devices to troubleshoot and implement a better WiFI solution at a remote site.
With this app we first found the WiFi in the apartment was a 2,4GHz only network. After updating to a 5GHz mesh network and adjusted the placement on the mesh AP we get a pretty good network.  And the most important from the user perspective, the throughput went up from approx 9mbs to 100 mbs.

Conclusion: often we don’t need expensive application to do minor adjustment and upgrades on a WiFi network.

And thank you, Vasco Costa, for the local tips you gave me.








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