Espargos and Reddit user h0m3us3r discovered an undocumented SDR reception mode in some ESP32 variants. This mode can capture the I/Q stream before the WiFi modem and transmit it to SDR software on an external computer. The feature, found in ESP32 chips that use earlier Tensilica hardware and in later ESP32 chips, works only in the receive direction; it supports the 2.4 and 5 GHz bands, depending on the microcontroller. Low-power chips that support only Bluetooth and the P4, which has no radio hardware, cannot take advantage of this mode.
Background
ESP32 is not a new name in the FikirPilot archive: in the last 90 days, we have published 11 news reports mentioning the name; the latest is dated October 1, 2026.