The FAA has posted a Flight Advisory warning that the Naval Aviation Warfighting Development Center is scheduled to conduct GPS interference testing over a large radius around Fallon, Nevada at various times between 18 and 21 September, 2017. The affected radius depends on flight altitude. The 50 foot above ground radius will be 222 nautical miles. Higher altitude radiuses extend much farther. See this PDF file for more details.
https://www.faasafety.gov/files/notices/2017/Sep/NAWDC_17-02_GPS_Flight_Advisory.pdf
https://www.faasafety.gov/files/notices/2017/Sep/NAWDC_17-02_GPS_Flight_Advisory.pdf