I looked up a few reviews for the CZH-5A. Some said 2 miles and some said 3000 meters. While it might be a crappy 5W, it's still too much for what I need.
I looked up attenuators--they cost more than the transmitter. I have a handful of 75ohm 20db attenuators on-hand but I don't know if they'll work correctly and safely with the 50ohm transmitter. Not to mention the input wattage exceeds that of the attenuators.