Here is an article on building a relatively inexpensive ADS-B receiving / sharing station based on the RTL2832U / R820T based DVB-T stick and a Mini-ITX motherboard. The complete system will run about $200. It in no way competes with commercial ADS-B receivers, but for a fraction of the price it can work pretty well and is a great way to get involved in the ADS-B monitoring hobby. You can use it as a receiving base station alone or add the Flightradar24 linux program to share your data. Basically the article combines using gr-air-modes,a RTL2832U dongle, with a small custom built computer for complete package. This may appeal more to those who have wanted to try this, but did not want to put Linux on their only computer or tie it up as an 24/7 ADS-B sharing system. The small computer and case wind up about the size of a standard radio receiver and will fit nicely with your other gear.