https://imgur.com/a/15CooO9
Here's an image of my setup, including the various important windows ^
I have tried using the Long Infrared and D-band wavelengths, and while I don't know for sure I think they both work in atmosphere given that the receiver is getting power. In the picture I'm using D-band. My power station is positioned about 4km inland of the launchpad so angle shouldn't be an issue. I'm fairly certain that the engine is getting power since disabling the receiver causes the engine to shut down due to lack of fuel. Also, the engine slowly becomes hotter and redder over time which I think is a good sign. Thanks for the response!