Here is a device that helps you detect commercial aircraft threats within a 100 statute mile radius. pingUSB is a compact USB dual-band ADS-B receiver that pairs with Visual Radar Server to provide you with reliable tracking.
pingUSB detects ADS-B equipped aircraft transmitting on both 1090 MHz and 978 MHz. It operates in -40° to +80°C temperatures. Costs under $115 at this time.