4 ms·
This is being operated at distances where you could just as easily hit the device directly with a hammer. To scale the distance up to just a couple of meters (
by mmagin 10y ago
This is being operated at distances where you could just as easily hit the device directly with a hammer. To scale the distance up to just a couple of meters (say about 50 times the distance), you'd need to scale up the power by about 50*50 = 2500 times.
I suppose it is conceivable that a suitcase-sized device could disrupt the actions of pacemakers of people walking within a meter or two. But it could just as well cause trouble with much more conventional means.
- madengr 10y agoActually even more since some near-field components fall off at 1/r^3.
- eternauta3k 10y agoCorrect me if I'm wrong: the near fields don't take out any energy if nothing's coupling to them. They're like a reactive load. The far fields, however, take energy out to infinity regardless of what's out there.
- madengr 10y agoYep, correct. I posted a link in another comment, but this is a good picture of all the components for small dipoles and loops. http://www.rfcafe.com/references/electrical/near-far-field.htm http://www.rfcafe.com/references/electrical/near-far-field.h...
- mlonkibjuyhv 10y agoQuick question: if you put a sink in the far field, does that increase energy drain at the source, or is the definition of the far field such that the field strength around the vicinity of the sink is the only thing practically affected?
- madengr 10y agoNo additional energy drain. In fact, one of the definitions of far field is that any thing in it can't change the impedance of the radiating antenna. There is a good article in this months IEEE APS magazine exploring where the far field begins. Coincidence I was reading it last night.
- M_Grey 10y agoWould those means leave a more obvious forensic trace? I mean... a hammer is going to leave a mark.
- Stratoscope 10y agoThere's probably a fairly large set of people who would never consider hitting someone in the chest with a hammer, but would fire up a device like this for the lulz, not knowing that someone with a pacemaker was within range.