Of course not everyone would have seen my tweet on this subject today, so I thought I'd share to the mailing list as well.
During most passes of the ISS where I'm working with the packet digipeater on 145.825, I also monitor 145.800 just in case there is any activity on that frequency.
For the first time in my personal experience, today one of the astronauts was randomly calling to see if anybody was listening. Of course I tried to reply on 145.800 simplex, but there are a number of possible uplinks and none of them were programmed into my radio. THEY ARE NOW!
FYI, here is a list of uplink/downlink combinations that I found online: https://issfanclub.com/frequencies
... and here is the downlink audio from today with the gaps removed:
https://www.qsl.net/k/k4kdr//files/2018-10-06--1858--ISS-voice.mp3
It was a real thrill and like so much of this hobby, a learning opportunity.
73
-Scott, K4KDR