Power/signal difference between mega and NodeMCU EDP8266 12E?

I just successfully got my code to output a proper 433mhz transmission with a mega and a cheap 433mhz 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 (powered by micro USB) 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).

Would really appreciate some help - or at least ideas to troubleshoot. Thanks.

Try powering the device with a separate power supply. The internal voltage regulator may not provide enough current for the transmitter.