On 10:50, Fri 19 Nov 04, Paul Schmehl wrote: > --On Thursday, November 18, 2004 09:32:27 AM -0600 Paul Schmehl > <[EMAIL PROTECTED]> wrote: > > >--On Wednesday, November 17, 2004 12:41:44 PM -0500 "Lachniet, Mark" > ><[EMAIL PROTECTED]> wrote: > > > > I find it hard to believe that this is possible. 2.4Ghz is the 9th > harmonic. By the time you get to the 4th harmonic of a signal, even in > very very noisy radiators, the strength of the harmonic component of the > signal is extremely minute. And, given the fact that one of those sensors > (which most likely does *not* truly operate in the 240MHz portion of the > spectrum) will have a very low output (Part 15 device), the 10th harmonic > of that signal will be undetectible as it will be at or below the level of > background noise.
Despite your disbelief, this is basic physics and a core component of musical amplification. It may not be solely due to the device. There may be building cavities amplifying the signal. The is a radio wave we're talking about after all. Sufficient Harmonic Oscillation can result in a boosted signal or Resonance: http://www.sasked.gov.sk.ca/docs/physics/u5c42phy.html > Finally, if a device managed to get past all of the improbabilities above, > the chances of it *accidentally* creating a signal that looked like an > 802.11 beacon packet, complete with preamble, header, etc is so off the > charts as to be laughable. Its not an accident. Cheap equipment = low quality control = no suppression and filtering. > One other thing... If that device truly was operating at 240MHz, then the > first harmonic would be 480MHz. I'm pretty sure that frequency lies in the > public service bands (ie fire/police). If not, its very close. Given that > and the fact that the first harmonic would be much stronger than the 9th > harmonic, I'm pretty sure someone in those bands would have complained > loudly to the FCC as they don't take intereference issues in those bands > lightly. Eh, not only does this happen, heres a recent story on one instance: http://www.technewsworld.com/story/37435.html > Paul Schmehl ([EMAIL PROTECTED]) > Adjunct Information Security Officer > The University of Texas at Dallas > AVIEN Founding Member > http://www.utdallas.edu > > _______________________________________________ > Full-Disclosure - We believe in it. > Charter: http://lists.netsys.com/full-disclosure-charter.html -- Esmond Kane Sys Admin HUAM DIT _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
