last updated November 15, 2021
WWV, WWVH start test modulation broadcasts
Radio stations WWV and WWVH are now broadcasting a test modulation produced by HamSCI as part of a joint effort between NIST and HamSCI intended to enhance ionospheric research. The broadcasts started during the 1800UTC hour on November 15, 2021.
The test signal is broadcast during minute 8 of WWV and minute 48 of WWVH hourly schedules, and will continue "for several weeks" according to the on-air announcement (minute 4 of WWV hourly schedule). The signal consists of various tones, chirps, and Gaussian noise bursts.
Here is a recording of the test broadcast from 2108UTC on 10MHz, recorded from a KiwiSDR hosted by N0EMP, located in northern Colorado. The frequency was 10MHz. 10MHz WWV 2108UTC 11/15/2021
You can also get more technical information from the WWV page at HamSCI: https://HamSCI.org/wwv