This same technique is also being investigated for use in radar systems that will use disruptions of television and cell tower signals to locate the positions of stealth aircraft that have been designed to minimize their cross section on traditional radar. One additional advantage is that such a system is passive, and would not give the tracked aircraft notification that it has been spotted, as the ping of an old-school radar would. posted by cobra_high_tigers at 6:51 PM on December 4, 2007
Awesome! posted by dhruva at 8:03 PM on December 4, 2007
Oh this is great. Pure dorky goodness. posted by quite unimportant at 8:19 PM on December 4, 2007
Part of me says "someone has too much free time" while the nerd in me LOVES THIS STUFF. posted by mrbill at 8:34 PM on December 4, 2007
This is a very clever, well illustrated website. Best of the web, indeed.
If you want to take it to the next level, you can use "passive radar" to hunt for UFO's. (pdf) posted by Tube at 9:09 PM on December 4, 2007
From what I've heard, stealth fighters have all sorts of issues in the modern era. From my limited understanding, they're the blackest things in the sky at most frequencies -- the problem is, now they're blacker than the sky itself! With all the ambient radiation coming from civilians, just looking for where there *isn't* noise is enough to find the jets. This makes sense from a design perspective -- during the design time of stealth fighters, sources of radiation would simply be bombed into submission. The concept of hundreds of thousands of illuminators creating an ambient glow was alien.
Now? Not so much. posted by effugas at 10:15 PM on December 4, 2007
He's lucky it's an analog TV signal. This sort of reflection often causes digital TV broadcasts to just stop working. Very frustrating when you live in an apartment building.
Interestingly, modern WiFi standards use these reflections to actually increase the available bandwidth. You can think of reflected path as a second channel.
Of course, I'm a software guy, not an RF guy, so corrections are welcome. posted by sdodd at 10:44 PM on December 4, 2007
Great find. His web domain name is interesting.
Frisnit! is an exclamation made by Roger Irrelevant, one of the more surreal (but not lalochezic) characters ever to populate Viz magazine, a puerile adult comic that had me peeing my pants when I was in college. posted by lalochezia at 11:04 PM on December 4, 2007
Great post! I wouldn't worry about having to pay extra for the license, your "special" TV now belongs to Torchwood and they will be coming to collect it shortly. posted by cgk at 11:13 PM on December 4, 2007
Talk about synchronicity, I was just reading about this yesterday.
Great post! posted by Sukiari at 12:28 AM on December 5, 2007
This is very cool, and explains a mystery of my childhood.
Folks growing up in the northern NYC suburbs in the pre-cable days will remember that, on certain TV channels (ones with transmitters on the Empire State Building, I believe,) there would appear a ghost image in the shape of the World Trade Center's Twin Towers.
I was always told it was, in fact caused by the WTC but never understood, until now, quite how it matched the shape so well. Reasoning things out with the help of this most excellent link, it would seem to be caused by a combination of fortuitous geometry between our house, the WTC and those transmitters as well as the fact that the WTC had the same width from top to bottom. Stations with transmitters ON the WTC, as one would expect, didn't suffer from this problem.
I'd post an example, but Googling "'World Trade Center' Television Ghost" these days yields plenty of links of the Art Bell-esque variety and not so much on picture interference. posted by Opposite George at 5:11 AM on December 5, 2007
You can detect stuff happening in the upper atmosphere by tuning in to an over-the-horizon TV channel and noting the doppler shift of the echo of the signal. This is most often used to count meteors, but you can also detect aircraft. The linked site provides a live signal streamed from MSFC. If you run the signal through a realtime FFT spectrum visualization you get a live picture of sorts.
Here's an example of what this looks like. Blips are often meteors; you start to recognize their shape if you stare at the signal long enough. The diagonal line is the doppler shift of something moving, probably an airliner. posted by rlk at 9:58 AM on December 5, 2007
Why do I have this strange feeling that this is one of those technological advances that people are going to "rediscover" several generations down the line in history? You know, like concrete, zero or the battery. posted by Pollomacho at 10:06 AM on December 5, 2007
*sigh*
Every day I find something that makes me realize I'm not really all that smart, and that people around me are doing things way beyond my ability to fully understand.
This was todays. posted by quin at 4:22 PM on December 5, 2007
« Older
An obscure 1911 British law requires a copy of eve...
| Agence Eureka...
Newer »
This thread has been archived and is closed to new comments
Subscribe
posted by DU at 6:46 PM on December 4, 2007