SIGbox is a "go-kit" for Signal Intelligence (SIGINT) enthusiasts with emphasis on capabilities in the VHF, UHF, and SHF spectrum. For completeness, HF spectrum related software is included for optional install. Describes both software and hardware used for this purpose.
SIGpi is the compute component of SIGbox built on a Raspberry Pi4 4GB RAM and 32GB microSD card. The SIGpi Build Script is run on your Raspberry Pi as user pi only AFTER you followed the Raspberry Pi Documentation - Getting Started guide.
A wiki that documents vendors of surveillance, wiretapping, and interception technologies, what their products are capable of, and the countries that buy their gear and what they use it for. Also discusses some of the issues surrounding large-scale communications interception.