4 ms·

Can you elaborate? Without some kind of analysis of the mistakes in the article, we don't really have a way to judge if we should belief your statement about th

by akerl_ 12y ago

Can you elaborate? Without some kind of analysis of the mistakes in the article, we don't really have a way to judge if we should belief your statement about the author, nor can we improve our understanding. A more descriptive listing of some of the issues with the article, or links to better resources, would rock.

madengr 12y ago
Well to start, the antenna generates it's own noise since it is not 100% efficient; i.e. it has a real resistance in addition to it's radiation resistance. If you put a real antenna in a box made of perfect electrical conductor, it would still generate noise, so you really don't halve the noise by increasing the gain 3 dB, you double the signal. Here is a good tutorial on phased arrays. It's actually a lot easier to think of it when receiving a skewed wavefront, and the phase shifters (delay elements) compensating for the delay. http://www.radartutorial.eu/06.antennas/an14.en.html http://www.radartutorial.eu/06.antennas/an14.en.html
- jerf 12y ago
  OK, while that seems like a valid tidbit if one has to implement this stuff, it doesn't seem like that's a helpful complication to introduce when trying to explain the basic concept.
abstrakraft 12y ago
Any time someone appeals to quantum physics to offer a handwaving explanation of something that classical physics covers just fine, watch out. Using path integrals to introduce interferometry is a waste of time, and in this case, just plain wrong. For a better source, I'd start with the wikipedia articles on beamforming, phased arrays, and interferometry (http://en.wikipedia.org/wiki/Beamforming http://en.wikipedia.org/wiki/Beamforming, http://en.wikipedia.org/wiki/Phased_array http://en.wikipedia.org/wiki/Phased_array, http://en.wikipedia.org/wiki/Interferometry http://en.wikipedia.org/wiki/Interferometry).
- MarkSweep 12y ago
  Both the beamforming Wikipedia article and the OP basically say "by having several out of phase antennas you can create constructive interference at the intended receiver of the signal". What am I missing?
  - judk 12y ago
    OP (and also Richard Feybnan) believes that QM provides a more intuitive explanation for the elusive "why" waves (interference) exist. Commenters here don't like that.

by akerl_ 12y ago

madengr 12y ago

Well to start, the antenna generates it's own noise since it is not 100% efficient; i.e. it has a real resistance in addition to it's radiation resistance. If you put a real antenna in a box made of perfect electrical conductor, it would still generate noise, so you really don't halve the noise by increasing the gain 3 dB, you double the signal. Here is a good tutorial on phased arrays. It's actually a lot easier to think of it when receiving a skewed wavefront, and the phase shifters (delay elements) compensating for the delay. http://www.radartutorial.eu/06.antennas/an14.en.html http://www.radartutorial.eu/06.antennas/an14.en.html

jerf 12y ago
OK, while that seems like a valid tidbit if one has to implement this stuff, it doesn't seem like that's a helpful complication to introduce when trying to explain the basic concept.

abstrakraft 12y ago

Any time someone appeals to quantum physics to offer a handwaving explanation of something that classical physics covers just fine, watch out. Using path integrals to introduce interferometry is a waste of time, and in this case, just plain wrong. For a better source, I'd start with the wikipedia articles on beamforming, phased arrays, and interferometry (http://en.wikipedia.org/wiki/Beamforming http://en.wikipedia.org/wiki/Beamforming, http://en.wikipedia.org/wiki/Phased_array http://en.wikipedia.org/wiki/Phased_array, http://en.wikipedia.org/wiki/Interferometry http://en.wikipedia.org/wiki/Interferometry).

MarkSweep 12y ago
Both the beamforming Wikipedia article and the OP basically say "by having several out of phase antennas you can create constructive interference at the intended receiver of the signal". What am I missing?
- judk 12y ago
  OP (and also Richard Feybnan) believes that QM provides a more intuitive explanation for the elusive "why" waves (interference) exist. Commenters here don't like that.