Crackling - switch off and on

After running volumio 1.5 on my Cubox-i2 for a while, it starts to crackle when I happen to stand in the line of wireless transmission from my modem to the Cubox. The scenario then is always this:

  • I have to switch off the power of the Cubox;
  • After a few seconds, I have to switch power on again;
  • I wait for the welcome sound;
  • The welcome sound crackles, and if playing music from this point on, it is (heavily) crackling/distorting too;
  • I have to switch off the power of the Cubox again;
  • After a few seconds, I have to switch power on again;
  • I wait for the welcome sound, which sounds ok now;
  • The system performs normal playback again, until the same story repeats again.

Sometimes I have to switch on and off more often to get it working, but generally it is like I describe here. Sometimes the crackling begins at a random moment (not standing in the way of transmission).

I am using a usb WiFi dongle;
I am using a Meridian Explorer USB DAC;
I am using airplay from my windows 10 laptop with Airfoil.