I would like use a Shure 444 microphone with a Behringer MIC800 preamp. What is the simplest way to achieve impedance matching for this mike? Thank you.

This is a great idea. I have been trying to start the very same thing!
I have been licensed only since 2010 and at present am a general operator. My equipment is a venerable Atlas 210X and two Kenwood 2 meter radios. This has enormous potential. We indeed could form a local group within a national scope. '73 KD0LMR ( Council 10490)  Please contact me at me profile email address.