FFT Bin Size Question

[cdknox]

First off, I appreciate the work put into both developing and maintaining the repository; it's cool software and it works well!

I started trying the software out using the SoapySDR interface on a HackRF at 20M samples per second and naturally found I needed to up the fft_size parameter. I bumped it up to the maximum supported 8192 for better channel resolution and things worked great.

In the name of a more is better mindset combined with the software being open source I wanted to see what would happen if I bumped it up to 16384 or at least find out why that limit was chosen. From reading the source I guessed it was to enable the GPU support on the raspberry pi, and upped the define of MAX_FFT_SIZE_LOG in the header file from 13 to 14. After changing the config file and recompiling though, it seems that change alone was insufficient.

The program does run but I never seem to show activity on any of the channels. I've enabled logging, debugging, and even broke out gdb to try to find something going awry. In my inexperience I don't see a reason that it wouldn't be working. My gut says something is wrong with some buffer length somewhere, but I've not been able to understand everything enough to suss it out.

All that to say, I'm curious if there's anything I'm missing that's obvious to someone more familiar with the software, or maybe trying to go that high on the fft_size parameter is entirely practically useless. Thanks in advance for any commentary provided!