I just successfully got my code to output a proper 433mhz transmission with a mega and a cheap transmitter I soldered an antennae on to. Signal was very strong and successful. I wanted to then use the same code and transmitter with a Node MCU EDP8266 12E so I could hook it to wifi.
When I tried to switch to a NodeMCU ESP8266 12, I used the same wiring and same transmitter, but I just got a very minimal signal (as observed with the USB SDR). It was sending something very weak, because when I unplugged power or the data pin I lost it....
For the Node MCU wiring, I wired the power for the transmitter to VIN, data to a data pin, and ground to one of the grounds. I tried switching from VIN to 3.3V but that just reduced the already weak signal (though it was still there).
.....I did then try to take a multi meter (without really knowing what I'm doing), and I touched the meter to the gnd pin and vin pin on the board. It smoked a little :(. Then my weak signal went to super weak. Did I fry the board? Any ideas what I should've done in the first place?