I give it FIVE Soldering Irons!
I found it on Amazon Prime. The workshop scenes remind me of ham workshops. The movie character Harry Caul was based on real-life Marty Kaiser. Was Marty a ham?
POSTSCRIPT (August 23, 2024): Yes, he is a ham! W3VCG! FB. Here is his web site:
http://www.martykaiser.com/fbi1~1.htm
https://en.wikipedia.org/wiki/The_Conversation
http://www.martykaiser.com/odyssey2.htm
Thanks to Roy WN3F for reminding me to watch this film. Roy found a clip that is reminiscent of hamfests: https://www.youtube.com/watch?v=joM5VDCIQg8