Eliminating Periodic Noise in the Speaker (Developer Edition)
Ashhar Farhan, VU2ESE
The LM380 audio amplifier is picking up the Wifi RF and it results in a noise that repeats every 8 seconds of so as a series of quick pulses.
The noise is not present if you use earphones as they bypass the LM380 audio amplifier.
The current solution is to just turn off the WiFi and use Ethernet instead for Internet.