I would like to test the range of my two HTs by myself while still operating legally. Anyone have any ideas of how I can accomplish this? The only way I could come up with was feeding audio into one at a fixed location with loop of my call sign. It is hard find an exact answer on this but it seems to me like I would operating out of compliance because I am not physically at my station.
tomnexus answer is excellent, as a practical matter when fooling around with microwave gear I would point a camcorder at a wall clock in a spot where it can hear the RX quite well and then hit record on the camcorder and take off for an hour driving around with a transmitter, and making a paper log of Exactly where I was and what I was doing at 16:27 or whatever. Sync your wall clock and your watch or whatever. Later, come home and watch the video. Hopefully you'll have something interesting to listen to on the recording as you correlate what you hear on the recording with your detailed log matching the recorded wall clock time.
I regret to report I never ran into problems like getting ranges so high that a mere one hour camcorder recording limited my data taking LOL. This is a small timer's strategy and those guys with 1500 watts and 200 foot towers probably cannot use this specific technique. But it would probably work with HTs?
It might not be legal to transmit unattended, depending where you live. It's also not ideal to transmit continuously; bad manners, and an HT will overheat pretty quickly.
You'll often hear hams using voice keyers I'm contests, to save them the effort of calling CQ. This would work, but think about what happens when someone responds saying you're in the way, or interrupting them, and you're not there to turn it if.
Rather do the transmitting yourself, and find a way to make an unattended receiver. This would always be legal.
A few ideas would be to: use a voice-activated sound recorder, or an app on a phone, then you would announce your location when you transmit. Or for more immediate feedback and less driving, find a way of calling your house, perhaps your phone or Skype could be set to auto-answer, so you can hear the received audio immediately.
Be aware that at the limit of the radio's range, the signal is very sensitive to how you hold the radio. (well, always, but it doesn't matter if the signal is strong). An experienced operator will swing the antenna around while receiving, to find the clearest position. Then freeze in that position when answering. So if you're transmitting blind, I recommend that you try at least four positions of the transmitter, at each location you drive to.
It's quite likely that your licence conditions specify that you may: Communicate with other amateur stations, and Make Test Transmissions. It's an experimental hobby, so go for it!