TechMinds: One Antenna Four Receivers with an Active Distributor
Over on his TechMinds YouTube channel, Matt has uploaded a video where he reviews a US$20 active antenna distributor that he purchased on Banggood / Aliexpress. An active distributor allows you to use one antenna with multiple radios, without incurring any distribution losses, which for passive splitters are typically at least 3dB per split. It does this by using an amplifier before the splitter. This is especially useful if you have a wideband antenna like a Discone.
The product comes with a built in battery, or it can also be powered via USB-C. Unfortunately it has a rather restrictive frequency range, only covering 100 kHz to 300 MHz.
Later in the video Matt shows the internal PCB of the product, showing its battery and circuitry.