I'm new to electronics and I have project that requires a signal to be sent a minimum range of 1 mile with a 12" wire antennae. I'm not sure how the signal is going to be arranged in terms of AM, FM, etc. It would be running off a 9v battery I think, with minimal draw.
At 500 GHz. it will easily be a DX record. At some lower frequency it should be possible. If that 12" was a quarter wave vertical then the ideal wavelength for your signal would 48" = 1.22 Meters or about 246 MHz.
If you had an ARL then your choices would be 146 MHz (2M band), 220 MHz., or 440 MHz. I should think a mile on 1-5 Watts should be doable.
I see that multiple batteries will last longer than a single because of the pull or something. Perhaps go with multiple d cells, underlying factor is to use as little of the battery as possible for limited interaction.