I listen to Astronomy Cast myself and recommend it too. I actually get the "raw" version before they edit it (https://www.astronomycast.com/feed/fullraw/) since it's amusing to hear what goes on behind the scenes!

I also greatly enjoy The Weekly Space Hangout (https://www.universetoday.com/feed/wshaudio/), and of course, Awesome Astronomy (https://awesomeastronomy.libsyn.com/rss).

I shall check Planetary Radio, which I haven't ever listened to. Thanks for the pointer.