I came across this talk by Jacob Appelbaum, where he revealed some tools used by NSA for the mass surveillance via TAO. At the end of the talk he also added that the NSA could actually beam a 1 kW RF energy from its portable continuous wave radar unit (CTX4000). Is this possible? It sounds like a serious threat to human safety.

  • Are you referring to this talk from 30c3? (RF stuff starts at about 49:40, 1KW Continuous Wave generators at 56:20)
    – Ladadadada
    Jan 7, 2014 at 20:31
  • Thanks @Ladadadada... I just noticed that I forgot to add the link. Yes, I'm talking about the CTX4000 CW Radar unit and the beacon (TAWDRYYARD).
    – Ken
    Jan 7, 2014 at 21:04
  • Apparent source of the slide used, via Wikimedia.
    – Oddthinking
    Jan 7, 2014 at 23:13
  • According to the link provided by @Oddthinking the output is only 2W but can be amplified using other equipment up to 1kW. Seems like this might be a better question for Electronics.SE
    – rjzii
    Jan 7, 2014 at 23:35
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    Why doubt the possibility and assume this to be a threat to human safety? Depending on local legislation, even radio amateurs are usually allowed to use transmission powers exceeding 1kW and there are several commercial radio and TV transmitters exceeding 1MW output power. Jan 8, 2014 at 12:46

1 Answer 1

  1. Is it possible possible that the NSA possesses portable radar systems that can put out 1 kW? Sure it is. There are mobile units able to output far more than just 1 kW.

    MIT developed a portable 250 kW radar system back during WWII. The TPQ-36 can output +20 kW and its larger cousin can go well over 100 kW.

  2. Define "portable". There are many possible setups which are both relocatable and produce relatively high output, but with varying levels of complexity in configuration, maintenance requirements, weight, and size. Depending on one's situation, "portable" can mean vastly different things.

  3. At 56:35 in the video you linked, Appelbaum begins discussing "a specialized technology for beaming energy into you and to the computer systems around you... with 1 kW of RF energy at short range" which he alleges the NSA uses. There a few problems with segment of his talk.

    • The alleged system is very vaguely described. As someone with a technical background, I was left with all sorts of questions about the details of how what he described would work. (This is not to say it is impossible. The world of cryptography and surveillance have produced far stranger technologies. Acoustic cryptanalysis is a fun one.)
    • Aside from making an unsubstantiated claim about the source of Hugo Chávez's cancer, Appelbaum gave no examples of where this technology has or is being used.
    • Appelbaum showed a few slide of electronics readily available to consumers which could be theoretically capable of doing what he said, but did not acquire and configure the equipment himself to provide a proof-of-concept. Even in the DIY oriented "hacker scene", PoCs are common; and according his own testimony, this should have been possible.
    • All he did was describe a vague possibility, gave no evidence of its use, and presented equipment which could conceivably be modified to output 1 kW of RF as proof of the existence and use of another technology. (Ignoratio elenchi.)
  4. Even given the issues listed under point number 3, if we were to assume the technology described by Appelbaum does exist and is regularly used, is it a threat to human safety? The short answer is no. The health effects you likely associate with "radiation" is actually ionizing radiation. (Any form of "light" is "radiation".) Standing next to a high energy RF source would be more likely to cook someone from the heat than riddle them with cancer.

    The World Health Organization agrees:

    RF fields are non-ionizing radiations (NIR). Unlike X-rays and gamma rays, they are much too weak to break the bonds that hold molecules in cells together and, therefore, produce ionization. RF fields may, however, produce different effects on biological systems such as cells, plants, animals, or human beings. These effects depend on frequency and intensity of the RF field. By no means, will all of these effects result in adverse health effects.


    * For adverse health effects, such as eye cataracts and skin burns, to occur from exposure to RF fields above 10 GHz, power densities above 1000 W/m2 are needed. Such densities are not found in everyday life. They do exist in very close proximity to powerful radars. Current exposure standards preclude human presence in this areas.

    RF fields between 1 MHz and 10 GHz penetrate exposed tissues and produce heating due to energy absorption in these tissues. The depth of penetration of the RF field into the tissue depends on the frequency of the field and is greater for lower frequencies.


    * Most adverse health effects that could occur from exposure to RF fields between

    1 MHz and 10 GHz are consistent with responses to induced heating, resulting in rises in tissue or body temperatures higher than 1C.

    For a fun an informative chart on "the ionizing radiation dose a person can absorb from various sources", take a look at https://xkcd.com/radiation/.

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    MIT developed a portable 250 kW radar system back during WWII. The TPQ-36 can output +20 kW and its larger cousin can go well over 100 kW. The possibility of mobile kW radar systems is so far within modern capabilities, it's like citing the sky is blue. If the question was merely about that possibility, I would have explained why it's technologically possible and listed several examples, but it is not. KC was actually asking about the system Appelbaum described. Jan 10, 2014 at 10:19
  • Of course you could have a portable emitter, a portable folding antenna, and a portable signal processor station, but you'd still need a rather large power source which would require a truck to move around, and probably another one for the fuel to run it.
    – jwenting
    Jan 10, 2014 at 12:35

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