The Wireman sells a thin-gauge stranded wire with a black coating that is essentially invisible from more than 20' away. Any loop, horizontal or vertical, or longwire made from this should work. If you decide you want to transmit, you can rig a covert hoist line with camo or other nature-colored paracord for quickly raising and lowering either self-supporting wire verticals, or dipoles in an inverted-V configuration (one hoist) or even flattop (three hoists.) You can easily hide radial wires and coax in your lawn, and only raise/lower a wire vertical each time you operate.