ISS Help!

Hi: My grandson and I are getting really frustrated...We have tried to listen to the ISS voice numerous times over the last couple of weeks with no success...We have an Elk antenna and a Kenwood D-72...We have never heard a peep of a transmission...I know they are sporadic in their operation from the ISS, but it seems like we would have heard something! Could anyone out there provide us with the real, valid, up to date frequencies that we should be using? I have seen both UHF and VHF frequencies listed...Thanks in advance for your assistance!

Steve KA1OWC
Kevin KE0MBK

Info at https://www.issfanclub.com/ is current

https://sourceforge.net/projects/gpredict/

Would this help?