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Post by Deleted on Mar 2, 2017 18:25:47 GMT
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Post by Druid Hills Radio on Mar 2, 2017 18:40:21 GMT
What will they think of next? |
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Post by End80 on Mar 3, 2017 4:24:59 GMT
What do they mean by using signals which are "already in the air" as means of not needing power?
“The challenge is that radio technologies like WiFi, Bluetooth and conventional FM radios would last less than half a day with a coin cell battery when transmitting,” said co-author and UW electrical engineering doctoral student Vikram Iyer. “So we developed a new way of communication where we send information by reflecting ambient FM radio signals that are already in the air, which consumes close to zero power.”
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Post by Boomer on Mar 8, 2017 3:41:00 GMT
This is a space-age topic, my intuition isn't locking in how the transmission technique works either. I've read about backscatter radar before, but can't fathom how this new transmission modifies an existing radio wave while using only micropower itself.
This makes me think of 'Free Power radios', anyone heard of those? Electronics magazines had circuits for them decades ago, where you could pick up a strong signal from a local AM broadcast station and rectify it with a full wave diode bridge, and get microamps of power out of it, to use to run other little tiny devices.
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Post by thelegacy on Mar 9, 2017 14:35:11 GMT
Popular Electronics talked about that years ago.
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Post by Boomer on Mar 10, 2017 5:44:29 GMT
It probably was PE, I can see the circuit in my head, with the diodes in a receiving circuit, rectifying both halves of the signal. Even the author talked about the fad of those radios, and was kind of skeptical about what you could do with the small amount of power, that Freepower Radios were kind of a hype thing. Cool you remember it though.
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Post by thelegacy on Mar 10, 2017 17:12:08 GMT
I think this would cause more FM interference from what I could tell. Now at first I thought it was about 87.9Mhz when they said unoccupied frequency. But reading further found their creating a sort of sub carrier that overlays the original.
This is part 15 done very wrong. Why not just legalize 87.9 and 87.7Mhz for such low powered information and hobby stations? FM is going to be ruined for sure if this goes too far.
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