Ok first off, mil guys and maybe some leo’s will know what we are mimicking by doing this and Im not going into thermal trouble shooting. Ive operated airborne cooled sensors for a while and so have the ppl involved in this. We’ve all spent 5-10k on thermals and we start debating which is better. The nerd of the group came up with a test.
Needed
1) 5 gallon bucket filled with water 40-60* above ambient
2) top for bucket
3) towel
4) 6ft+ aluminum stock we used 1.5”x1”x6.5’ (must be solid, pipe will cause a stove pipe effect)
Let the bar stock cool and become cold soaked on a cold/cool night DO NOT touch it with bare hands. Cut a small hole into the bucket top which it will fit through. Fill the bucket, 40* night use 80* water. Stick stock in bucket so it stands vertically. Wrap the towel around the base of stock to seal it. We dont want warm air from the water inside the bucket escape. You need level ground with preferrable sky in background. Background needs to be a uniform temp is all. The bar will be close to if not invisible to the thermal. We let it cool on saw horses to keep it off the ground. Thermals must be of same objective size to be apples to apples. Back off 50m and watch the heat rise up the stock. The scope that sees the heat the highest on the stock is the most sensitive.
Yeah, you brainiacs are already thinking with distance and stock size you could get effective resolution.
Im not saying which did what but between 4 of us we had about everyone represented. Im not posting results but I was humbled and I have the highest budget. Plus this kinda thing starts A LOT of poop tossing on the web. Looking at pics of pigs doesn’t do a lot for true comparison. Oh no beer during test or yeager to keep warm (you forget why your there)