Raspberry Pi 3B USB WiFi Upgrade with EDUP EP-AC1651

Because I KNOW I’m going to have to do this again…

One of my various DIY devices (it’s the hot tub) involves a raspberry pi 3B situated kind of far away from my wifi router, and through a handful of walls. Often, the signal strength received is so bad that the device is completely offline, or else suffers massive packet loss, which tanks responsiveness of the controller UI served up via webpage.

I bought a EDUP EP-AC1651 from Amazon mainly for the price. It uses the Realtek RTL8811CU chip and doesn’t work with RasPi OS out of the box, so I had to find a driver.

I came across https://github.com/fastoe/RTL8811CU_for_Raspbian#realtek-8811cu-driver-for-raspberry-pi-os and followed the instructions “For Raspberry Pi OS 5.10” directly to get online.

After a reboot, both the onboard wifi and the AC1651 were connected to my router. I ran ifconfig to determine the IP and MAC address of the new wifi adapter so I could reconnect after changing settings. I also transferred the static DHCP reservation on my network to the new adapter’s MAC address. I then disabled the onboard adapter with sudo ifconfig wlan0 down. Once I verified I could still access the Pi with the other adapter/IP address, I ssh’d in again and added dtoverlay=pi3-disable-wifi to /boot/config.txt to disable onboard wifi permanently and force all activity through the USB adapter.

After a few minutes and a couple reboots, the new adapter got the reserved IP address and speeds improved. Actually not as much as I’d hoped, though.

Interesting aside about beamforming routers

Interestingly, I can improve performance of the stock raspi by walking over there with my iPhone and running a speed test. At first, the iPhone performance is better only by the margin of its overall RF performance vs the Pi (which, the iPhone is a lot better). But after a few seconds, the router beamforms strongly in that direction to satisfy the iPhone’s demand, and that actually has the secondary effect of making the raspberry pi wifi performance ALSO much better. This was my usual fix, but it’s a bit cumbersome and unreliable, and doesn’t work when you’re not physically present at the house, hence the upgrade.