It's a real thing. There are several online services that use them.This is what a HIT is asking me right now, is this legit??!? sounds shady
We are looking for people to host a small receiver on their property. The receiver is smaller than a shoebox, and it captures public aircraft flight information.
We will drop ship it to your home. Simply plug in the power cord and ethernet cable. Ideally you host the box top of your building, not at the center of your building.
We will pay you $10 at the end of each month when you keep it plugged in and online 99.9% of the time (that gives you about 35 minutes of downtime each month). You will receive a $50 bonus after you have done this for 12 months.
https://en.wikipedia.org/wiki/Automatic_dependent_surveillance_–_broadcast