Hi Igor,
Great news that Airplane Mode helped!
For some Dell wi-fi cards, the radio power can be reduced which can help with interference. (Also, many users have reported that if they have a Dell or “Killer” brand wi-fi adapter which does not support adjustable power, that they have contacted Dell and explaining the issue, Dell has sent them a replacement Intel wi-fi card which supports adjustable power.)
Can you please see if your card supports this setting and try reducing the power to see if it helps?
Also, sometimes connecting to a 5GHz wi-fi network rather than 2.4GHz can help.
!](https://d2r1vs3d9006ap.cloudfront.net/s3_images/1688575/ScreenShot2018-01-03at9.50.58AM_inline.png?1515002677)](https://d2r1vs3d9006ap.cloudfront.net/s3_images/1688575/ScreenShot2018-01-03at9.50.58AM.png?1515002677)
