you can use the app called "Clock Wave" to set your atomic clocks.
It very cleverly uses the iPhone/iPad speaker(s) to generate an RF signal that the clock can receive.
You have to put the clock antenna right next to the phone/iPad speaker for it to work.
It has an option to emulate WWVB, which is what I use to set my Casio Pro Trek watches, when I can't get WWVB over the air (for whatever reason). It can also emulate BPC (Shangui China), JJY (Fukuoka, Japan), MSF (Anthorn, Cumbria, UK), and DCF77 (Mainfilngen, Germany).
https://cw.rzapps.com/