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Comment by chrisbrandow | Hacker News Reader

So, I’m dumb about this stuff, but I have a wireless keyboard that uses a WiFi dongle to connect. I’ve lost connection with it a few times on my new m1 Mac. I had never lost connection with it in the previous 5 years.

Could this be related to the phenomenon the authors are describing?

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Dongles are usually not Bluetooth or WiFi. But sometimes share the same frequencies. The M1 MacBooks have been having Bluetooth issues.

Not applicable to your dongle issue, but for others: One weird trick that works without fail for me is disabling WiFi, connecting your Bluetooth devices, and reenabling WiFi. Don’t know why it works.

To elaborate on this for GP, if a keyboard has its own wireless dongle, it is usually in the 2.4GHz frequency band, same as used by microwave ovens, Bluetooth, and 2.4GHz Wi-Fi. The keyboard and/or dongle should list the frequency band it uses.

The Wi-Fi chipset in the computer is not used at all here. The dongle presents itself to the computer as a USB human input device, just like any other USB keyboard or mouse.

This is why you can use a keyboard like this to access the BIOS settings at boot time on a PC, which you can't do with a Bluetooth keyboard.

That said, the wireless connection between the dongle and the keyboard is subject to interference by other 2.4GHz devices.

So one thing to make sure of is to connect to a 5GHz Wi-Fi network, not 2.4GHz. And as you mentioned, Bluetooth can also interfere.

I had an interesting case of this some time ago. I was using a ThinkPad TrackPoint Wireless Keyboard II with a desktop computer on the floor several feet away. This keyboard can either use Bluetooth or its own USB dongle; I used the latter so I could access BIOS settings.

It worked great - except when I used my Bluetooth Apple AirPods with a phone (either iPhone or Android). Then the keyboard would start missing characters or repeating them wildly.

The solution was to use a USB extension cable to put the keyboard dongle on my desk near the keyboard itself. That improved the signal between the two and eliminated the Bluetooth interference.

Yeah same I thought my laptop broke because my AirPods and my mouse weren't working. Turned out it's the other laptop connected to 2.4GHz across the room.

Are you using a USB-C dongle? That is known to cause issues with things operating in the 2.4GHz spectrum (such as Bluetooth and your keyboard dongle).

It's not so much the Type C connector causing the problem but rather the high data rates of SuperSpeed USB (or whichever one it is that causes the trouble; I can't keep track of the USB-IF's recent garbage). So Type A (9-pin) connectors are vulnerable as well. But given that a BT or BTLE dongle can't really run very fast, I doubt they're using anything above USB HS (480Mbps) and therefore unlikely to interfere at 2.4GHz no matter what the connector.

Yeah, the dongles themselves work fine, it's other USB 3 devices that cause the problem (eg. hard drives or USB 3 hubs).

Bluetooth is also affected by the interference. The advantage of a dongle is that you can use an extension cable and move the transmitter away from whatever is causing the interference.

USB-a

Is it really wifi? Or is it Bluetooth?

Bluetooth wouldn't need a dongle on a modern computer. But I'd be surprised that it's wifi and not some other frequency radio communication.

They always seem to come with a dongle just incase though, and sometimes people use the dongle despite having bluetooth, or plug them in and then connect to the computer's built-in bluetooth.

The problem with Bluetooth is that it just doesn't work well when you want to use one keyboard or mouse with multiple computers.

For this reason I prefer the dongles. Want to use your mouse on a different Mac? Just plug the dongle in a different computer.

I don't know how often I ended up at the password prompt with no way to type the password because the keyboard didn't connect, or was connected to a different Mac, and I had no idea how to get it to connect to the Mac I was trying to start.

This is why I like the Logitech MX keys/mouse. Can have multiple dongles and just press a button to choose which one you connect to.

Logitech also has a Bluetooth variant of this where the mouse will have 3 different "personalities" that you can associate with different devices and then switch with a button. As far as the host devices are concerned it's 3 different mice so there's no switching involved.

It works great and it's the best of both worlds. Convenient and no dongles (Bluetooth on my MacBook was very reliable for a mouse).

WiFi and Bluetooth support is often provided by the same chipset.

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