1,500AC(43,560SF/AC) = 65,340,000 SF. Assuming a relatively square property, your 1,500 acres is about 1.5 miles per side, or ~2 miles on the diagonal. That's nothing for a five watt hand held with a decent antenna.
Buy these, install the large antenna and see what happens.
How are you getting around? Side-by-side, truck, jeep? If the handhelds don't work due to terrain or vegetation a mobile unit with a mag mount antenna should.