Wi-fi: internet sharing keeps dropping off and on

Why do I have difficulty with Wi-Fi or Bluetooth devices when USB 3 devices are attached to my computer?

Some USB 3 devices can generate radio frequency interference that can cause Wi-Fi and Bluetooth devices operating in the 2.4GHz band to have issues communicating with your computer. Here are some tips to avoid this issue:

• If your USB device has a cable long enough that you can move the device, place it away from your Mac—and make sure not to place it behind your Mac, or near the hinge of its display. The antennas for Wi-Fi and Bluetooth are located there, and USB 3 devices placed there might interfere with your wireless connections.

• If you're using adapters or dongles on a Mac computer with Thunderbolt 3 (USB-C) ports, plug them into the front port on the left side of your Mac, or into the ports on the right side (if your computer has them). These ports are the farthest away from the antennas, making interference less likely.

• To avoid interference on the 2.4GHz band using Wi-Fi, try using the 5GHz band instead. You can change this on your wireless base station. Bluetooth always uses 2.4GHz, so this alternative isn't available for Bluetooth.

from:

Using USB devices with your Mac - Apple Support

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Well now we know. When sharing, that report will only tell you the channel.

 Menu > about this Mac > (system report) > Network|Wi-Fi

and see if there is more information. It may look something like this, but the payload is near the end:

en2:

Card Type: AirPort Extreme  (0x14E4, 0x8E)

Firmware Version: Broadcom BCM43xx 1.0 (5.106.98.101.28)

MAC Address: 00:24:36:af:94:8f

Locale: FCC

Country Code: US

Supported PHY Modes: 802.11 a/b/g/n

Supported Channels: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 36, 40, 44, 48, 52, 56, 60, 64, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 149, 153, 157, 161, 165

Wake On Wireless: Supported

AirDrop: Supported

Status: Connected

Current Network Information:

Bennet-AlderAssociates:

PHY Mode: 802.11n

BSSID: 88:…

Channel: 36,1

Country Code: US

Network Type: Infrastructure

Security: None

Signal / Noise: -74 dBm / -87 dBm

Transmit Rate: 216

MCS Index: 13

Other Local Wi-Fi Networks:

Bennet-AlderAssociates:

PHY Mode: 802.11n

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I do not think it is a network problem, based on what you have posted so far. I think your MacBook Pro is simply too busy doing something else to properly serve the Wi-Fi for your attached device.

Items I suspected might turn up in your report:

adware or malware

third-party anti-virus, cleaner, or memory management add-ons

Dropbox, Backblaze, or similar non-Mac-native so-called syncing apps

Huge amounts of unsatisfied syncing with iCloud

Third-party VPN and/or useless "security" software

syncing to google and Chrome

disk drive issues or lack of RAM memory

a quick and easy experiment -- do you get same results five feet away?

If you were debugging the other way around (Router to Mac) I would ask you to post the snapshot from Holding The Option key while clicking the Wi-Fi Icon on the Menubar. I honestly don't know whether it works for this case. looks like this normally:

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What Mac is it, exactly, by year, early mid late, screen size, retina or not and processor speed?

What MacOS are you running?

You are using 802.11ac, and achieving a transmit rate of 702Mbits/sec, very respectable. You should not be having issues. MCS index 8 means you are using a complex pattern, 256 QAM to achieve this data rate, likely over two antennas using an 80 MHz data channel centered around channel 48.

If you were having too much interference, that speed and MCS index would drop back over a few minutes to a slower speed and a more mundane pattern.

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Using an Internet speed tester from that same computer, do you have enough speed to support the rest of the connection on to the Internet?

It is possible something is running your macBook that is making it too slow to maintain the connection properly. You can use this little "discovery" Utility, specifically developed by a senior contributor to create a pre-laundered report that can be posted on the forums.

Using EtreCheck to Troubleshoot Potential Mac Issues

https://discussions.apple.com/docs/DOC-250000632

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