The picture of the two inkjet printed antennae that the guy is holding in the original URL... do not tally with the words 'harvested TV and radio signals'.
He is holding an enlarged print-outs of two Fractal wide band aerials.
They might be able to power the latest military microchips, but to report (transmit) back to a base, as to what frequencys the 'enemy' was using, would require an extra TX chip hooked into a proper power source.
The original blurb tends to state that radio waves in the air can be used to harvest various electronic devices.
Maybe... but not by using those Fractal aerial, 'sucking' micro-watts from VHF radar, or similar installations.
Yes, the minute RFID devices that Hitachi manufacture, could be powered using Fractal aerials....since they are virtually invisible, being about 0,05mm X 0,005 thick.
Used I believe embedded in paper packaging, and/or high value Banknotes. Then again RFID chips are interrogated using a high frequency power source when taken out of a fixed area. So no point in using RFI chips...so I assume the military do have an as yet unknown use for these Fractal aerials.
The only type of aerials that can take RADIO power out of the air.. is in the medium or longwave wavebands, put out by the normal radio stations.
For instance you can build a Crystal Set, they require NO power whatso ever and this allows you to listen to dozens of radio stations around the world. (Useful during a National Emergency?)
Building a good quality Crystal Set using a full wave circuit, and schottky diodes or similar and specialised csapacitors (prehaps a 1-2 Farad 3volt cap) will give you enough power to run a Crystal Set PLUS an amplifying chip that uses very little power, like a ZL70250 radio chip.
Years ago crystal sets used earphones of about 2000 ohms resistance, but today one can use a pair of Ceramic earphones of at least a million ohms (barium titanate?)
which put out a loud enough sound, that you could attach a horn to.
http://www.instructables.com/id/How-to-make-a-fractal-antenna-for-HDTV-DTV-plus-/
