Specification:1. working frequency : vhf(172-240mhz) / uhf(470-860mhz)2. vswr : ≤1.53. impedence : 75 ω4. gain : 25±3dbi5. reception range:80km6. size:128*60mm7. cable length: 5meters8. connectors : f male9. polarization : vertical10. voltage : 5v11. power supply connector : usb12. current consumption : 20ma13. operation temperature : -45 ~ 85°c14. storage temperature : -45 ~ 85°chow many free channels can you get?1.find out where the broadcast towers in your area are located.2.discover how many free channels are available from your local broadcasters3.provides lists of available channels, coverage maps, and dynamic signal analysis maps for any location.please kindly be noted1. the indoor hdtv digital is specially designed to receive free hdtv broadcast signals (such as abc, cbs, nbc, fox, cw and pbs). supported formats: 1080p.