When I want to test an antenna or anything I just call CQ a few times on FT8 and within seconds I get dozens/hundreds of reports and can see how far/what direction my signal is going.
The one advantage of this is that my wife told me that she felt bad for the little clock that had been waiting 15 years to receive that signal which gave me the opportunity to get out some of my ham gear and show her.
Pretty easy to generate the WWVB signal, I've written various MSF simulators that look like they'd be easy to tweak to generate WWVB. For reasonably accurate time though you'd want to have something running NTP to drive the simulator. Maybe you've got a time-nut [0] nearby.
The one advantage of this is that my wife told me that she felt bad for the little clock that had been waiting 15 years to receive that signal which gave me the opportunity to get out some of my ham gear and show her.