I have to try it but it looks like running Cygwin on windows should provide the free open source way for me to use Tar to back up to LTO5 tape
http://cygwin.1069669.n5.nabble.com/Quantum-LTO-4-tape-drive-and-Cygwin-1-7-td54235.html
https://www.experts-exchange.com/questions/20832880/Restore-Unix-Tar-Tape-in-Windows.html
https://www.cyberciti.biz/faq/linux-tape-backup-with-mt-and-tar-command-howto/
https://cygwin.com/ml/cygwin/2013-08/msg00340.html
https://cygwin.com/ml/cygwin/2009-10/msg00527.html