> For the complete documentation index, see [llms.txt](https://ctf.zeyu2001.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ctf.zeyu2001.com/2021/dawgctf-2021/babys-first-modulation.md).

# Baby's First Modulation

GNURadio

## Problem

Our listening station caught this RF recording of a guy reading off the flag. It's FM modulated.

rf1.iq: <https://drive.google.com/file/d/1TSOt9YrljsE8ETSlXRsGLy3Qo8M3g3jQ/view?usp=sharing>

This IQ file was saved in standard GNURadio format (complex, 32bit float I, 32bit float Q)

Author: nb

## Solution

Open the `.iq` file in GNURadio and apply the demodulation.

![](https://3167364547-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MX1bWRlBzHpEPe1TYDD%2Fuploads%2Fgit-blob-d3639c2fd6ca946ceda1c5df53c90dcffc84b9c6%2Fb0c03badeafb4ff0a95941d66aae441d.png?alt=media)