In this update we cover the isolation of ERASynth's RF output from Wi-Fi signals radiated by the on-board ESP8266 module.
We received some questions regarding the WLAN signals coupling to the RF output. Some people were concerned that phase noise would increase with WLAN module (ESP8266) active. Our tests show that there is no need to worry about WLAN. First of all, whether you use the on-board WLAN or not, WLAN signals are all around us. Secondly, we have taken very serious measures to cope with all kinds of couplings and leakages on the board. As you can see in the detailed PCB picture on the campaign page, ERASynth PCB is partitioned to protect sensitive areas from the outside world and from the other noisy areas on the board itself (such as switch-mode regulators, MCU etc...). There is a tremendous amount of filtering on every supply and control line. The picture below shows ERASynth's RF output connected to a spectrum analyzer while the WLAN module is activated.
ERASynth RF Output Spectrum while Wi-Fi Module is active.
As you can clearly see in the picture above, on-board WLAN signals are suppressed more than enough. With that said, if you are still uncomfortable with the WLAN interface, you can disable it completely using the serial interface.