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emf [2020/03/03 03:34] – Changed note about Vehicle Occupation detection. bpaddock | emf [2023/01/18 00:28] (current) – Added MuRata In-Cabin Radar for Child Protection bpaddock | ||
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+ | |||
+ | ---- | ||
+ | |||
+ | The electronic company MuRata released information today [Jan/ | ||
+ | |||
+ | The goal is to detect that infants and young sleeping children do not accidentally get left in a hot or cold vehicle, where they are likely to rapidly expire. | ||
+ | |||
+ | The methodology of detection is what is open for debate. | ||
+ | |||
+ | Today' | ||
+ | |||
+ | The ASSUMPTION is that this 60 GHz signal will cause no short or long term health issues. | ||
+ | |||
+ | Detection of children left in vehicles is being mandated or is about to be, by various politicians in Europe and the US. MuRata' | ||
+ | |||
+ | What happens when a complex modulation of 5G at 28.375 GHz, 60 GHz from In-Cabin Radar, 77 GHz from external vehicle Radar (We are all being exposed via new fancy tech such as self-braking, | ||
+ | |||
+ | Texas Instruments and NXP also are working in these areas. | ||
+ | |||
+ | https:// | ||
+ | |||
+ | Microwave News covers this general field of how signals affect us, and has been doing it for decades. | ||
+ | https:// | ||
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https:// | https:// | ||
+ | ---- | ||
+ | |||
+ | ====== DIY Faraday Cage ====== | ||
+ | |||
+ | The message below if from Clive Robinson, who once was a Real World | ||
+ | ' | ||
+ | spell his way out of a paper bag, we've all gotten use to it.. This | ||
+ | is his recipe for a DIY Faraday Cage: | ||
+ | |||
+ | < | ||
+ | Clive Robinson January 21, 2014 8:14 PM | ||
+ | |||
+ | @ Carl ' | ||
+ | |||
+ | "... I'd purchase aluminium foil and line a closet/ | ||
+ | it being sure to ground the foil. Obviously make all purchases with | ||
+ | cash and at various stores, etc. Jamming might also be possible, but | ||
+ | more easily detectable by the listening party" | ||
+ | |||
+ | A single or double layer of aluminium foil is not going to be very | ||
+ | reliable for various reasons. | ||
+ | |||
+ | If you are going to do this at home then you need to do it "flat pack" | ||
+ | style. | ||
+ | |||
+ | You need to make up some light weight wooden frames just like those | ||
+ | artists do to stretch canvas for oil painting. However instead of | ||
+ | stretching canvas you stretch chicken wire such that it goes around | ||
+ | the frame. You take two of these and screw them together such that you | ||
+ | have both wooden frames inside an outer skin of chicken wire. It's | ||
+ | best to put thermal insulation of the fiber type in between as this | ||
+ | helps deaden sound. Don't rely on the compression contact between the | ||
+ | two sides of chicken wire lace the together with copper wire and | ||
+ | solder it to the chicken wire (it's usually galvanized so will take | ||
+ | solder if you clean it, flux it and use a hot enough iron). You can | ||
+ | make these flat pack frames up to 8x4 using standard DIY timber packs. | ||
+ | |||
+ | Eight of them (1 floor, 1 ceiling, 2 end walls 4 for side walls) will | ||
+ | make a small box/room you can build in a shelf for a computer and an | ||
+ | office chair to sit on. However you need to make the floor frame much | ||
+ | stronger (unless you've over done the fasting diet craze ;-) | ||
+ | |||
+ | Obviously one of the frames needs to have a door built in and this is | ||
+ | a little more complicated. Make a smaller frame of about 6x3 this is | ||
+ | the door, the frame holding it is made such that the Inner frame has a | ||
+ | smaller hole than the door to make a half to one inch jamb all around | ||
+ | the outer frame has a hole just large enough to take the door. You | ||
+ | then need to make a conductive door seal. The easiest way to do this | ||
+ | is with 75ohm TV coax, if you strip the outer plastic insulation you | ||
+ | have a soft foam plastic core with a woven braid outside it. Staple | ||
+ | this two the door and jamb such that you have two concentric circles | ||
+ | one on the jamb one on the door such that they don't touch each other. | ||
+ | You will need to come up with a door handle and bolt system such that | ||
+ | the braid makes good contact with the chicken-wire covering the door | ||
+ | and covering the jamb. | ||
+ | |||
+ | Having bolted it together you then line the inside with aluminium foil | ||
+ | such that you have four layers. You put in the first layer horizontal | ||
+ | with the edges overlapping by an inch or so the second layer vertically, | ||
+ | the third horizontally the fourth vertically. Hold each layer in place | ||
+ | with small lengths of sticky tape. Using copper staples hang a layer | ||
+ | of thick hessian (sack) cloth over this then with copper plated marine | ||
+ | screws carefully put a layer of thin protective ply wood over this. | ||
+ | |||
+ | There is a minor problem you next need to solve and that's ventilation | ||
+ | the easiest way to do this is when making the end wall frame that goes | ||
+ | over the computer desk make an internal frame the size of a small | ||
+ | bathroom/ | ||
+ | insulation in here but do ensure the chicken wire covers both sides | ||
+ | of the frame. Mount the extractor on the outside after carefully | ||
+ | making holes in the aluminium foil. Make a similar arrangement in the | ||
+ | bottom of the door only don't add an extractor, put one of those | ||
+ | aluminium ventilation louvers with the sliding plate on either side, | ||
+ | make sure one has the louver slots vertically the other horizontally. | ||
+ | |||
+ | Your next problem is getting power into the unit. To do this you need | ||
+ | two dicast aluminium boxes with screw on lids and two IEC (kettle | ||
+ | plug) EMI/EMC chassis mount filter connectors. Drill holes and mount | ||
+ | the IEC connectors one in each box, screw one box on the inside and | ||
+ | one on the outside with the holes to take the cable aligned wire the | ||
+ | two IEC's together. Connect a power strip board to a kettle lead and | ||
+ | plug it into the inside IEC connector, then for obvious safety reasons | ||
+ | screw a wooden block in behind it to stop it being pulled out and | ||
+ | allowing fingers to touch the pins in the IEC connector. On the outside | ||
+ | you need one of those " | ||
+ | current trip devices in the wall socket and a suitable length kettle | ||
+ | lead to plug into the IEC connector on the external box. Remember it's | ||
+ | only good for about 5 Amps. | ||
+ | |||
+ | You then need to get an EMC test receiver or appropriate spectrum | ||
+ | analyzer to do inside spectrum to outside spectrum comparison to see | ||
+ | how good a job you have done. | ||
+ | |||
+ | If you know what you are doing you can fit a " | ||
+ | through bypass" | ||
+ | two glanded chassis mount N-type connectors one on the inside the | ||
+ | other on the outside. It enables you to have a broadband amp and | ||
+ | antenna on the inside of your box and the spectrum analyzer on the | ||
+ | outside with it's tracking generator output fed through the bypass to | ||
+ | the amp and antenna. When not in use you screw plugs onto the | ||
+ | connectors with hard shorts in them to prevent leakage. | ||
+ | |||
+ | A less dangerous way to do it is to make up a temporary lead you have | ||
+ | fed through either the door louvers or extractor unit. | ||
+ | |||
+ | If you can't see any leaks from the outside put the spectrum | ||
+ | analyzer inside and the amp and antenna outside and run the tests | ||
+ | again, remember to move the antenna from place to place outside. It | ||
+ | can be a quite time consuming effort and in some cases take longer | ||
+ | than it did to build the box... | ||
+ | |||
+ | Usually if you are certifying a commercial RF cage, you are looking at | ||
+ | allowing four working days for a couple of engineers/ | ||
+ | |||
+ | With appropriate antennas you can check how well your box screens. It | ||
+ | should be good for 60db or more of attenuation depending on how well | ||
+ | you fit the door and gaskets. With care you can get it to the point | ||
+ | where average test equipment is not sufficient to give readings above | ||
+ | it's noise floor. | ||
+ | |||
+ | The real question is do you value your privacy to the point of a | ||
+ | capital outlay of around 1000USD and a week or two of time? | ||
+ | |||
+ | ... | ||
+ | |||
+ | The most drastic I've had to do is with TEMPEST kit where the debug | ||
+ | port was a striped bare fiber optic cable through a pin hole in the | ||
+ | screened case, screened with RG174 coax with the inner pulled | ||
+ | out. Expensive and a right royal pain in the "sit upon". | ||
+ | |||
+ | Oh one thing to remember when dealing with RF follow the " | ||
+ | earth" policy. Otherwise you will get "RF loops" which are the EM | ||
+ | equivalent of "audio howl around" | ||
+ | causes all sorts of nastiest in the EM spectrum as well as general | ||
+ | instability, | ||
+ | </ | ||
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+ | |||
+ | ---- | ||
+ | ToDo: | ||
+ | |||
+ | DNA Sequence Reconstituted from Water Memory | ||
+ | |||
+ | https:// | ||
+ | |||
+ | https:// | ||
+ | |||
+ | |||
+ | " | ||
+ | Frontiers in Antennas covers: | ||
+ | |||
+ | * Ultra-wideband antenna arrays using fractal, polyfractal, | ||
+ | aperiodic geometries | ||
+ | |||
+ | * Smart antennas using evolutionary signal processing methods | ||
+ | * The latest developments in Vivaldi antenna arrays | ||
+ | * Effective media models applied to artificial magnetic conductors and | ||
+ | high impedance surfaces | ||
+ | * Novel developments in metamaterial antennas | ||
+ | * Biological antenna design methods using genetic algorithms | ||
+ | * Contact and parasitic methods applied to reconfigurable antennas | ||
+ | * Antennas in medicine: ingestible capsule antennas using conformal | ||
+ | meandered methods | ||
+ | * Leaky-wave antennas | ||
+ | * Plasma antennas which can electronically appear and disappear | ||
+ | * Numerical methods in antenna modeling using time, frequency, and | ||
+ | conformal domain decomposition methods | ||
+ | |||
+ | https:// | ||
+ | |||
+ | |||
+ | More on Plasma Antennas in " | ||
+ | Theodore Anderson. | ||
+ | |||
+ | https:// | ||
+ | Linked therein is how to inactivate C19 at 222 nm. | ||
+ | |||
+ | Ted's web site is: | ||
+ | https:// | ||