Ask Fran: Vacuum Fluorescent Displays, Microwave Radiation, & The Ecliptic.
Added 2021-03-25 00:15:46 +0000 UTCMore to come!
Comments
They were lucky [if] they didn't get injured/sick!
Eric At Random
2021-03-30 01:56:13 +0000 UTCI'm Back :D Great stuff as always.
MVVblog
2021-03-25 18:09:41 +0000 UTCYour explanations are great for most levels of understanding. I heard as story years ago of someone who took the mesh off their microwave door so they could see the food better and wondered why it didn't cook so well! Glad you're enjoying making these videos.
Dr Andy Hill
2021-03-25 11:17:05 +0000 UTCMy brother worked on the flight deck of a carrier. They could hear the sweep of the radar in their ear protectors. He told a story of a photographer wandering past a hangar during a radar test on a plane. All his flash bulbs ignited.
Steven Ruhl
2021-03-25 02:28:07 +0000 UTCGreat explanations for complex concepts! You could be a college professor if you wanted to. You explain things down to a level where it's actually fun to learn. That's a rare trait among us technical people. I was told at one time that microwaves normally travel in a very straight line, thus making microwave communication towers for the old Bell System very effective. One tower would shoot a very directional line of microwaves to the next tower, allowing for curvature of the earth, and that's how a lot of long distance services by AT&T/Bell System worked before we had satellites in space and optical fiber on the ground. I think they are still used. Not sure. But I was told by a weather radar tech at work that the reason the fan in the microwave is there is not to cool things down, but to scatter the straight microwave beam from the magnetron in all different directions via its spinning blades. I never was stupid enough to defeat all the safety mechanisms and point the output of a microwave oven magnetron to a specific surface but, in theory, just that one spot would heat up severely, depending on what it was made of. Of course I expect the beam would also bounce all over the place creating a true radiation hazard. When McDonnell Douglas switched from 16mm movie cameras to video cameras and recording equipment they experienced something unexpected when filming actual F-18 operations on a carrier deck. Every time the largest radar dish on the conning tower swept over their location, there would be pretty severe distortions in the video and audio. So, every time that dish rotated, these broadcast-quality cameras were being hit with some pretty serious microwave energy. I don't know much about all the radar equipment on aircraft carriers, but I assume it was probably an extremely high-powered radar designed to detect very small objects at great distances. It made me wonder if the carrier deck personnel were being irradiated beyond what they ever expected based on the problems the video cameras were having. The solution wound up being copper foil tape being wrapped around every surface of the cameras and recorders, except the viewfinder eyepiece and main lens. This "shielding" worked pretty well, but was not 100% effective. For those McDonnell Douglas camera people who were trained and certified to fly in the back seats of F-15s and F-18s also found that the aircraft's extremely powerful radar also caused distortion in unshielded video equipment. It's truly amazing how much electrical power those fighters create to feed the exotic radars that require high power to do what they do best. When an F-15 "painted" the rear of another F-15, where the back seat had a video camera operator, the distortion really got bad. So, I guess that old video equipment could have served as a poor man's radar lock warning receiver. Now pilots can put GoPros on their helmets and not get any distortion. I don't know if they they wrapped them with copper tape, though. Microwave technology is really amazing and it's fascinating to see how well we have harnessed its potential. Thanks for the explanation! I was told not to stare intently into the face of a running microwave, but knew I'd have to be there a loooooong time before I received any major cell damage, if ever. The explanation of the screen of holes on the door was really awesome!
Matt Wietlispach
2021-03-25 02:10:44 +0000 UTC
