Even if location services are disabled, wifi scanning can destroy wireless performance. Scanning will essentially pause communications on your current wifi connection, as the hardware has to hop to other channels to scan for available access points. Depending on how long this takes, you could see an adverse impact on your current connection.
Applications and plugins can trigger this behavior by trying to interact with the locationd service, such as web browsers or QuickTime (it apparently has known bugs that will cause the application using qt libraries to trigger wifi scanning). This will manifest itself as frequent or periodic ping spikes and streaming performance drops (audio or video conference calling will drop quality or cut out entirely).
Video and voice calling, particularly over wireless, can be severely impacted. You should disable all wireless devices and use ethernet only if you require anything related to audio or video over the network. If your office is wireless only, you may need to re-evaluate your hardware / OS options.
One way to confirm this is to do the following:
1) open Apple's "Console" Application
2) add "scan" as asearch term to the top-right
3) scroll to the bottom of the log pane so new events show up at the bottom as they occur
4) open the terminal / iterm2 app and ping either '1.1.1.1' or your local router
5) click on your wireless icon and see if your ping lag spikes occur at the same time as the "locationd" messages
If you have location services disabled, you will see the following:
default 12:01:58.360773 -0400 locationd WIFI_LOC: location services are disabled, ignore scan result
default 12:01:58.907701 -0400 locationd WIFI_LOC: location services are disabled, ignore scan result
default 12:01:59.469546 -0400 locationd WIFI_LOC: location services are disabled, ignore scan result
default 12:02:00.089787 -0400 locationd WIFI_LOC: location services are disabled, ignore scan result
default 12:02:00.922026 -0400 locationd WIFI_LOC: location services are disabled, ignore scan result
If location services are enabled, you will see the following:
default 12:03:25.995118 -0400 locationd WIFI_LOC: onWifiNotification, notification, <private>, kNotificationScan, scanType, <private>, <private>, inject, <private>, inProg, <private>
default 12:03:25.995167 -0400 locationd WIFI_LOC: scan result, scanType, <private>, <private>, currentRequest, <private>
default 12:03:26.546485 -0400 locationd WIFI_LOC: onWifiNotification, notification, <private>, kNotificationScan, scanType, <private>, <private>, inject, <private>, inProg, <private>
default 12:03:26.546536 -0400 locationd WIFI_LOC: scan result, scanType, <private>, <private>, currentRequest, <private>
default 12:03:26.705880 -0400 locationd WIFI_LOC: processScanResult, aps, <private>, fIsUseNetworkLocationProvider, <private>, fIsUseTileManager, <private>
. . .
The ping latency may improve with location services disabled, but the problem likely will not be eliminated. You must identify the application, service, or plugin that is triggering wifi scanning.
Hopefully someone from Apple can chime in with a simple method of doing so (like monitoring / tracing to capture apps). In the event they don't respond, you might try taking a look at capturing additional logging...
https://www.howtogeek.com/211034/troubleshoot-and-analyze-your-mac%E2%80%99s-wi-fi-with-the-wireless-diagnostics-tool/
https://superuser.com/questions/585473/debugging-osx-airport-wifi-connection
Related links:
https://superuser.com/questions/1142798/experiencing-high-latency-on-wifi-every-other-second-with-macos-sierra
https://superuser.com/questions/1142798/experiencing-high-latency-on-wifi-every-other-second-with-macos-sierrahttps://apple.stackexchange.com/questions/310218/stop-destroying-network-performance-every-time-an-app-scans-for-wifi-networks/312388
https://lostdomain.org/2017/06/17/qt-qnetworkaccessmanager-causing-latency-spikes-on-wifi/
https://bugreports.qt.io/browse/QTBUG-65586?gerritReviewStatus=All
https://discussions.apple.com/thread/8523377