OK, how dis possible? - Page 1
Forum section: electronics / general

author: Ultrapurple
author_rank: Super Contributor
timestamp: March 03, 2021, 08:59:22 am
content: Either my thermal camera has discovered a whole new set of temperatures *way* below Absolute Zeroor the correction algorithm has (temporarily) crashed.Discuss! Extra points will be awarded for humour and/or definitively re-writing established laws of physics.

author: Nominal Animal
author_rank: Super Contributor
timestamp: March 03, 2021, 09:26:22 am
content: Interestingly, -514.3°C + 273.15°C + 273.15°C = +32.0°C .It really looks like a temperature scale conversion bug. Celsius and Kelvin scales only differ by the zero point, 0°C = 273.15 K.

author: Ultrapurple
author_rank: Super Contributor
timestamp: March 03, 2021, 10:08:24 am
content: Smart thinking, Nominal Animal!I do know that there was something resembling an inverted high-end bit in the algorithm (or NUC data or data or comms or...), which is why there is a fairly large, fixed-pattern swathe of 'bad data'.That particular camera has a chequered history (though I've had it from new). With the right driver software it produces perfectly good pictures; it's only a specific set of (repeatable) circumstances when the picture gets munged like the example above.

author: Vipitis
author_rank: Frequent Contributor
timestamp: March 03, 2021, 11:16:09 am
content: Cosmic rays, CIA spy radio towers.It's not something in your control.

author: tszaboo
author_rank: Super Contributor
timestamp: March 03, 2021, 11:17:19 am
content: Does your lady tell you, that you have very cold hands?

author: Ultrapurple
author_rank: Super Contributor
timestamp: March 03, 2021, 12:29:58 pm
content: Quote from: Vipitis on March 03, 2021, 11:16:09 amYou mean likeOperation Easy Chair?

author: Vipitis
author_rank: Frequent Contributor
timestamp: March 03, 2021, 12:51:20 pm
content: Not specifically, but a long time ago you posted something where a radio tower or cell phone one interfered with the imaging.

author: Ultrapurple
author_rank: Super Contributor
timestamp: March 03, 2021, 03:02:28 pm
content: Well remembered! If I recall correctly, I was using an early Therm-App to watch a loading coil at the base of a ham radio transmitting antenna running about a hundred watts. The Therm-App was on the end of averylong USB active extension cable and whenever the transmitter was keyed above a certain power, the Therm-App stopped. At lower powers, there was interference on the thermal image.The electric field strengths close (50cm) to a transmitting antenna of any kind can be high (and essentially depend mainly on the transmitter power). The UK telecoms regulator is presently rolling out a requirement to evaluate field strengths and concomitant safety zones for all transmitters of 10W or more, irrespective of frequency or purpose. (I say 'all'; I'm not sure if non-fixed transmitters are included).Even radio hams, who have traditionally been exempt from just about everything, are included, much to their consternation. The national society for radio amateurshas published guidance.But I digress! The upshot of looking at the loading coil with the thermal camera was to determine that it was quite lossy - getting warm - and so it was replaced with a lower-loss design.