Thanks for the reply, Gil! That is the writeup I found to be the "nicest." That implementation only launches direwolf, NOT rtl_fm piping output to direwolf. My limited Linux command line experience is what is holding me up here. If I had some direction on how to use the following command line with the systemd approach:
rtl_fm -f 144.39M -o 4 - | direwolf -n 1 -r 24000 -b 16 -
Maybe the execstart command would support the piping syntax, but for now I can not get it to work.
Thanks,
Paul