WiFi Signal Strength with Raspberry Pi 4 Cases

Note: You may want to check out a more recent article I wrote on WiFi performance: Raspberry Pi WiFi Performance Revisited (Feb 2021)

Following a comment from Geir on a previous blog post, where he asked if the metal enclosures which may help assist cooling of the hot Pi 4, could impact WiFi signal strength.

Whilst I only have a small number of different cases to test with. I’d wanted to follow on from my post looking at the impact on cooling from different cases by examining their impact on WiFi signal strength.

Bluetooth testing is out of scope.

Test Environment

My home is probably an atypical setup, with the home WiFi coverage provided by 4 dual (2.4Ghz & 5Ghz) access points. 2 x Apple AirPort Express (802.11n 2nd generation), 1 x Apple AirPort Extreme (802.11n 5th generation) and 1 x Apple AirPort Extreme (802.11ac). This setup came to be after eventually deciding to standardise on one manufacture to aid with device roaming between AP. I’d like to replace this with some Ubiquiti PoE access points at some point in the future, but that’s for another day.

Each Pi test configuration was positioned in the same place, tests were then conducted as close together as practically possible to avoid influence from atmospherics and other external sources

Testing method

With the Pi 4 housed in each enclosure, connected via both WiFi and Ethernet. I run an ssh session into the Pi and use the command: sudo iwlist wlan0 scan to list all the APs the Pi can currently see and record the WIFi signal strength of each of my APs the Raspberry Pi 4 can see from where it resides on my office desk. The command is repeated 5 times for each test configuration.

There are other APs visible to the Pi from neighbouring houses, but we’re not going to worry about those here.

Test Results

Measurements of WiFi signal strength use dBm (0 to -100), closer to zero is better. A simple description of WiFi signal strength can be found here.

Access PointMake/Model2.4 GHz
Channel
5 GHz
Channel
AP1Apple Airport Express (802.11n 2nd Generation)136
AP2Apple Airport Express (802.11n 2nd Generation)644
AP3Apple Airport Extreme (802.11n 5th Generation)11108
AP4Apple Airport Extreme (802.11ac)836

Note: AP1 is approximately 1m away from the Pi under test, under the desk the Pi was sitting on.

I will be moving either AP1 or AP4 to a different 5GHz channel, they are both currently on “Auto” setting for 5GHz channel selection.

2.4 GHz WiFi

The first graph shows the averages from the tests for each configuration. The second graph shows all the measurements, to highlight where some configurations had patchy signals, not getting reading from an AP for all 5 test runs.

2.4GHz WiFi performance
Click to enlarge
2.4GHz WiFi data
Click to enlarge

5GHz WiFi

The first graph shows the averages from the tests for each configuration. The second graph shows all the measurements, to highlight where some configurations had patchy signals, not getting reading from an AP for all 5 test runs.

5GHz WiFi performance
Click to enlarge
Click to enlarge

Summary

  • Metal enclosures of any kind have a measurable impact on WiFi signal strength.
  • The generic aluminium case performed the worst, with poorer readings across all APs.
  • 5GHz signal strength on the Pi4, on the whole, is worse than 2.4GHz.
  • The plastic cases don’t have a significant impact on WiFi performance, but the Pimoroni Pibow Coupé 4 case performs the best of these. possibly due to the plastic standoffs raising the Pi a little higher off the desk.
  • Of the metal enclosures, the FLIRC cases performed the best in the 2.4Ghz tests, perhaps helped by having a plastic base. In the 5GHz tests, the Armour Twin Fan Radiator case did surprisingly well, outperforming the FLIRC. (Though as you’ll know if you read my other posts, I have a preference for passively cooled cases).

Product Links

Amazon links are affiliate links which help support the site, where possible I’ve used links which should take you to the product in the Amazon store in your region. Links to other suppliers are included for your convenience.

5 thoughts on “WiFi Signal Strength with Raspberry Pi 4 Cases

  • 24th February 2021 at 3:29 am
    Permalink

    Hi,

    I have some question.
    are you using same channel width for 802.11n and 802.11ac?
    if you use same channel so what is the performance of them.
    Can you share with me both configuration of 802.11n and 802.11ac for raspberry pi 4?

    Reply
  • 17th March 2021 at 10:15 pm
    Permalink

    Hi,
    you wrote, that the FLICR Case performes best. But as far as I see the Armour Aluminium Radiator performes also very good in 2.4GHz and 5GHz WLAN (some channels are better than FLICR, some worse).
    Comprising, why is the FLICR your winner?

    Reply
    • 18th March 2021 at 8:32 am
      Permalink

      Hi,
      In the 2.4GHz tests, the FLIRC case was better in 3/4 of the tests, with the Armour case only better against AP2 on Channel 6, it wasn’t able to get a result from AP4 on channel 8.
      In the 5GHz tests, the FLIRC case was better in the same on AP1, better on AP2 and worse on AP3, neither getting a result from AP4.
      Giving the following “wins” relative to each other:

      • FLIRC: 4/8
      • Armour Aluminium Radiator: 2/8

      The twin fan variant of the radiator case did better than the non-fan version, specifically in the 5GHz tests:

      • FLIRC: 3/8
      • Armour Twin Fan Aluminium Radiator: 4/8

      So you’re right, I based my conclusions mainly on the 2.4GHz results, and will update to clarify. However as I’ve noted in my updated look at WiFi performance, I’m not that happy with the testing methodology I originally used in this post.

      Reply
      • 20th March 2021 at 8:22 pm
        Permalink

        Thanks for your fast respronse and your additional clarification 🙂

        Reply

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