One Dongle, One Owner
Definition
A design rule for shared radio hardware: an RTL-SDR dongle is a USB device that only one process can claim, so exactly one program is allowed to open it and every consumer is served from that program's reads. Two rtl_433 instances on the same dongle both fail, intermittently; with one owner, a single RF read refreshes a local graph and feeds a public uploader, and a non-blocking lock enforces the rule at runtime.
Sources