EverSet ES100 receiver kits are available exclusively from UNIVERSAL-SOLDER®
https://universal-solder.ca/?s=Everset&post_type=product
NIST WWVB website:
https://universal-solder.ca/product-category/atomic-clock-radio-receiver/everset-es100-wwvb-bpsk/
Enhanced WWVB Broadcast Format:
http://www.nist.gov/pml/div688/grp40/upload/NIST-Enhanced-WWVB-Broadcast-Format-1_01-2013-11-06.pdf
HKW Test equipment provides a signal generator supporting the enhanced protocol:
www.hkw-elektronik.de/englisch/index.php