An hour out of a 600MAH pack seems low. It might have something to do with the antenna being collapsed though. Not only does it generate heat, but it's a LOT less efficient at generating heat than it is RF waves. Try it with the antenna fully extended on a fully charged pack and see what kind of time you get.

BTW, for setup purposes, if you remove the battery, can't you use the charge jack to power the transmitter? Also, most people might not recommend it, but if you pick up a regulated DC power supply of the correct voltage and current raiding and hardwire it to wooden dowels with metal tacks on the end, you can bench test your radio all day without touching a single battery. It needs to be a very high quality power supply though, as the ripple in your average DC power supply will glitch your transmitter badly, and might actually harm it.