In response to the California Public Utilities Commission's request for more information about the radio frequency from SmartMeters™, PG&E submitted on November 1, 2011, a public filing
that contained detailed data from a field study of 88,000 SmartMeters™. That field study, performed by PG&E's wireless network provider, Silver Spring Networks, showed that a typical SmartMeter™ communicates intermittently throughout the day for a total cumulative period of approximately 45 seconds per 24-hour period (half of the tested meters transmitting for less than 45 seconds, and the other half transmitting for more). In the study, a small number of SmartMeters™ in the outer range of the population communicated somewhat longer than 45 seconds-per-day, which resulted in an overall mean duration of approximately 62 seconds-per-day. In addition, that detailed data reflected power densities of 0.35µW/cm² (0.058% of FCC limit) for electric SmartMeters™, 0.01µW/cm² (0.0033% of FCC limit) for standard gas SmartMeters™, and 0.059µW/cm² (0.02% of FCC limit) for extended-range gas SmartMeters™.