Radios and Chipsets
Every WiFi radio is a transceiver, meaning it can transmit (TX) and receive (RX) information. Not every radio is created equal, however, as their capabilities may differ significantly. Software support in particular may inhibit an otherwise fine bit of silicon. In particular, modes of operation may be restricted either by hardware or software.
For the most part chipsets from Atheros have excellent support, with a few RaLink and Realtek chipsets having made a name for themselves in the infosec community as well. Radio chipsets typically interface with a computer over a bus like PCI or USB. A WiFi radio is often called a wireless network interface controller (WNIC or Wireless NIC).
On the other hand a SoC (System on a Chip) is a special WiFi chipset which combines the radio with its own CPU. WiFi SoCs, unlike typical x86-based PCs, traditionally run MIPS based CPUs. While lower in clock speed than their PC counterparts, they’re specifically optimized for high performance networking. Both the WiFi Pineapple NANO and TETRA operate on Atheros SoCs.