Smith] from the University of Washington, which purports to construct a low-throughput RF transmitter from little ... offering 13.6 dBi of gain. The receiver is a pair of high-gain LNAs, a ...

He connected the data pin from his RF receiver to an audio plug and inserted it in the line-in jack of his computer. Using Audacity he recorded the signal as he pressed buttons on the transmitter.

The transmitter sends short bursts of single-tone RF signals at low and high frequencies (700 to 1,000 megahertz and 2.3 to 2.5 gigahertz) through the soil sample. The receiver's power spectrum ...