I’m attempting to record audio from my flight lessons. I don’t need the video, just audio to review when I’m not up in the air. I watched a few videos and looked around the web and so far I cannot find to much information. I have some items I found on amazon that I think will work but how can I be sure. On a side note I heard audio in recording is necessary for clear recording directly off the radio. Is this true and how can I tell if the recorder has this feature? Thank you!