virtually all of the energy radiated by a rubee base station or a rubee radio tag is contained in the magnetic field (h), not the electric (e) field. this stems from the fact that the rubee antennas are short relative to the wavelength (about a mile and half or 2 km at 131 khz), and rubee operates in the near field. a typical emitted e from a rubee base station is about 40-50 nanowatts, and h is about 900 milligauss (90 μt). finally, rubee is a packet based protocol in which only one end of the communication at a time generates fields, that is, a rubee tag is a radiating transceiver.