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I recollect reading in a newspaper in england, maybe 20 years ago, that someone had been prosecuted for stealing electricity from a radar. This was detected because the air defense radar had a black spot in its propagation field and apparently he hooked up a load of wires in his roof. I an certain I read this, but it seems physically impossible. Is this false memory syndrome or could it have happened? Could it happen with a microwave link if they pass over head? Thanks – dave

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    \$\begingroup\$ This could almost be at home on skeptics.SE or physics.SE. \$\endgroup\$
    – JYelton
    Dec 18, 2012 at 0:35
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    \$\begingroup\$ This would be like prosecuting someone for stealing energy by basking under a street lamp. \$\endgroup\$
    – Kaz
    Dec 18, 2012 at 1:10
  • \$\begingroup\$ This is amusing. Years ago, during the installation and testing of traffic control radar at the Denver International Airport then under construction, seemingly anomalous slow-moving aircraft were detected to the west just grazing the Rockies. As these blips disappeared without any small planes landing, engineers wondered if it might indicate some illicit activity. No such thing. The blips weren't Cessnas, but automobiles crossing the Continental Divide at Loveland Pass (3,655 m)on Interstate 70! The beam was duly adjusted. \$\endgroup\$
    – A Enriquez
    Oct 27, 2021 at 19:00

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Most radars transmit high power pulses but have low duty cycles so the average power is not very high. They also generally transmit over a narrow beam that is rotated either mechanically or electronically to cover a full circle. Also the power in the beam falls dramatically with range. Based on those three features, the average amount of power that intercepts a single roof of a house would not be very much. In any event, one would then have to efficiently receive this power and convert it to low frequency AC in order to use it for powering one's household. I can't give more quantitative answers without knowing the radar parameters and the distance between the radar and the house, but I seriously doubt the story. Additionally, air defense radars by definition are designed to survey the sky and not the ground. Thus the radar beam would not be directed low enough to intercept a house other than by sidelobes which are much lower in amplitude than the main beam.

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As Barry said, a house is so low that it shouldn't be in the way of the radar beam in the first place. However, even if it was this would still be nonsense. First, enough radar power is normally transmitted thru the house that harvesting it would be meaningful, it would cause a health threat to those living there. Second, what if the house happened to have a aluminum roof? That would reflect the radar instead of absorbing it, but either way it wouldn't serve its supposed intended purpose. If this myth were true, then aluminum roofs would have to be outlawed too.

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  • \$\begingroup\$ +1, also it's typical to ground metal roofs as part of lightning protection - a grounded roof would absorb energy. \$\endgroup\$
    – sharptooth
    Dec 18, 2012 at 13:13
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    \$\begingroup\$ @sharp: Actually grounded or not has nothing to do with what it would do to a radar beam, which would be to reflect it in both cases. Think of a mirror for visible light. It reflects just as well whether floating, grounded, or electrically connected to something else. The reflection is a result of the physical properties of the material at its surface up to a wavelength or so in, and has nothing to do with its potential. There is no closed conduction path even if it were "grounded". \$\endgroup\$ Dec 18, 2012 at 13:40
  • \$\begingroup\$ How is that different from a en.wikipedia.org/wiki/Crystal_radio that has a long antenna wire connected to a grounded receiver? \$\endgroup\$
    – sharptooth
    Dec 18, 2012 at 13:53
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I asked a friend of mine who served at a USAF radar installation where they used over the horizon ICBM detection radar. We're talking MW output here. He was saying that close to the dish site there were lines on poles etc. that said "do not go higher than this when dish active" and in the offices/barracks, if someone left the lid on a pot/kettle that the pot would buzz every-time the sweep would go by.

So that might give you a lead to go look at to verify independently.

I'd say it's possible, but the circumstances would need to be particular. You'd need to be able to get close to a very high output Radar system, which are typically remote or limited access.

Here is a link to WHO site giving some context for energy levels. http://www.who.int/peh-emf/publications/facts/fs226/en/

Aircraft traffic control is ~ 100 KW. and here is a snip from that site.


However, because its power is radiated over a large surface area, the power densities associated with these systems vary between 10 and 100 W/m2 within the site boundary. Outside the site boundary RF field levels are usually unmeasurable without using sophisticated equipment. However, small military fire control radars on aircraft can be hazardous to ground personnel.


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Perhaps you're looking for a slightly different story/rumor. I heard it in the 1970s like so: a farmer in the UK discovered that his wire fences were electrically "hot," so he connected up an electric heater and was using it to heat his outbuilding. It turned out that he was kilometers from a BBC antenna farm, and his long-fences heater was punching a hole in the antenna pattern for the "World Service" AM transmissions being beamed at Europe. In the story this was not illegal, so the BBC cut a deal. They paid to have power lines run out to his remote location.

Big BBC transmitter is Rampisham, out in Dorset farmlands. Unless there are other megawatt World Service sites, that's probably the one. (If the story happened at all, I mean.)

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  • \$\begingroup\$ There are the Voice of America transmitters in Spain - I think these are the only AM transmitters that can do double atmospheric bounce and can reach Siberia. \$\endgroup\$
    – Lior Bilia
    Oct 27, 2021 at 19:44
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It is definitely possible to take some of the energy transmitted to the house. Not very much and not very usable. All you need to be able to get some energy is an antenna.

Its much like the old crystal radios, it is certainly possible to get some energy from RADAR. It will, as others have stated, however only be when they transmit in your direction and it will probably only be very little power. I don't see why one would be prosecuted because of this for another reason than breaking some kind of building regulating law.

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  • \$\begingroup\$ thats very usefull, forgot i asked this question ages ago. Maybe it was stealing from pylons nearby that would work I guess and be at the right frequency? \$\endgroup\$
    – dave
    Jul 4, 2020 at 14:03

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