These are web-based radio players (e.g., using proxy sites, direct IP streams, or lightweight HTML5 players) that can play live stations even when networks block typical streaming services like Spotify, Pandora, or iHeartRadio.
In modern systems, the "block" is almost entirely digital. Software-Defined Radios utilize general-purpose processors to process signals. A smartphone or modern transceiver may physically be capable of transmitting across a wide band, but the firmware contains "whitelists" of approved frequencies. The "unblocking" of such devices often involves flashing custom firmware to bypass these software checks. unblocked radios
To understand the "unblocked" paradigm, one must first understand how restriction is implemented in modern radio frequency (RF) engineering. These are web-based radio players (e