Is there a way to get a professional propagation map for my VHF 50 watt repeater?
Not sure about "propagation" but you can check an estimate of "coverage"
Without promoting anything, and with the normal "Your Milage May Vary" and "There might be others" disclaimers, the site I use for checking coverage is:
You need to do the following:
- setup a user account (free)
- setup a base/home location
- then setup a "coverage"
The free edition of this website will only allow frequency inputs in the HAM/Amateur radio bands.