Talk via Satellites and maybe the Moon

speaker: Roland Turner event: GeekCampSG 2015 ** types of radio license free, low power: wifi, bluetooth, zigbee licensed spectrym: radio/tv broadcasters, marine, amateur ** stuff amateurs do

• meteor scatter, bouncing signals off the meteor trail ** issues to consider
• satellite tracking
• doppler effect
• hidden transmitter effect ** moonbounce
• very very weak due to distance and reflectance loss, ~ 10^-25
• lots of noise: moonshine, milky way background ** fresnel zone plate antenna
• flat reflector
• price scales linearly ** high electron mobility transistors ** cooling the dish with liquid nitrogen to reduce thermal noise ** JT65 modulation 12 byte payload, 1 minute to transmit