Cavity Wall advice

[John Rumm]

To put that into some context, when I worked on military IR surveillance kit in the late 80's some of the thermal sensors designed for avionics use had a thermal telescope on the end of them - all "optics" machined from germanium, and if memory serves a mildly radioactive coating applied to the interior surfaces. They started at £150K for the smaller ones!

These systems were higher than SD video resolution in the thermal band - basically using highly polished video line synched rotating polygons to project and scan the image onto a fixed SPRITE detector.

False colour seems quite popular in the consumer space, but never really seemed to be of interest for military or avionics. (you have a choice of black hot or white hot, and could adjust the gain and offset (the functional equivalent of contrast and brightness))

[Theo]

Not just cost, export controls start getting tricky when exporting higher resolution/framerate models that could be used for military purposes.

We have a Flir One gen2 at work - it works reasonably well. Worth noting that the older gen2 Flir One has a higher thermal resolution (160x120) than the current gen3 Flir One (80x60) - basically they renamed the $200 One to the $400 Pro (160x120) and then released a worse $200 new model. Buy an old one if you can.

What's nice about the Flir One is there's also a spot temperature measurement you can bring up, to give you a numeric reading. I don't know the accuracy (don't have means to measure surface temperature to calibrate it) but it seems reasonably good.

Theo

[Andrew]

Do you go munro-bagging in a string vest and plimsoles, Rab C Nesbitt- style ?.