I have never made a run that long with rg-11, actually very rarely use rg-11, if I run coax it is usually rg-56 or 6. I would probably use a video baulan and run it over twisted pair
I have mini u-store warehouses with the passive (non-powered) Muxlab 500009 units running around 2500 feet and no problems.
They are on individual cat5 runs to a master enclosure on one of the units. They are then cross connected on a BIX block with a 25pr burial cat5 running to the climate controlled master building.
My longest run is around 2500ft with a color camera but Muxlab recommends a max distance of 2500 for B&W and 2200ft for color.
I am getting my power at the enclosure unit and sending it down spare pairs on the individual cat5 lines.
Going 1800ft with the power probably isn't a good idea. Can you get electrical power closer to the camera location to install the power supply?
I used to run cameras at a horse track the back stretch camera was about 2500-3000 feet of coax many tracks were just RG/6 you just need a strong signal to start with.
Like TP says I think the key is to locate the camera power as close to the camera as possible when you're using coax.
I installed many cameras on some very long runs (well over 2000 feet) using RG59 when that was the latest, greatest cable and the distance wasn't much of a problem for us. On the other hand remembering where the power supply for each camera was became a different story entirely. :shrug: