Solo long range shooting tips.

[Sticks]

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Also, some phones may be able to use wifi direct, and communicate with each other, in locations where cell coverage is nonexistent, but I doubt it has the range to stretch across the distances involved.

Not without spending some decent money on antennas, boosters, and batteries. My multirotor, I put another $300 into the transmitter to receive the signal from the camera, and that only got me out to 2500 feet reliably (some days more, some less), and that was also at 350' AGL. Drop down to 3', and the signal just won't make it from the camera with out putting a booster and antenna on the top of it.

For the $500 you would spend on a DIY camera system, I'll walk or drive out to look at my target and give my barrel a chance to cool down.

Next option is getting some 1 MOA steel made for the range you want to shoot at.