WIFI devices

[halo2_god]

Hey, everyone im looking at alot of wifi divices mostly $60.00 and cheaper.
http://www.bestbuy.com/site/olspage.jsp?_dyncharset=ISO-8859-1&id=pcat17071&type=page&ks=960&st=wireless+usb+device&sc=Global&cp=1&sp=&qp=crootcategoryid%23%23-1%23%23-1%7E%7Eq776972656c6573732075736220646576696365%7E%7Ecabcat0500000%23%23a%23%23ba%7E%7Enf403%7C%7C243530202d202439392e3939&list=y&usc=All+Categories&nrp=15&iht=n
and http://www.bestbuy.com/site/olspage.jsp?_dyncharset=ISO-8859-1&id=pcat17071&type=page&ks=960&st=wireless+usb+device&sc=Global&cp=1&sp=&qp=crootcategoryid%23%23-1%23%23-1%7E%7Eq776972656c6573732075736220646576696365%7E%7Ecabcat0500000%23%23a%23%23ba%7E%7Enf403%7C%7C4c657373207468616e20243530&list=y&usc=All+Categories&nrp=15&iht=n
So saying this much im looking for a fast wide ranged device. I want something around 200 - 300 foot with only 1 wall in the way atleast 54 MBPS and i also was looking at some devices that had 5.0 GHz that would also be nice. Could any one help me with my selection.

[Your Amish Daddy]

Isn't 5ghz 802.11a?

[Thrax]

Yes.

[halo2_god]

Isn't 5ghz 802.11a?
Just to let you know a GHz means 1 billion radio waves per a second(Which would mean a faster connection(signal) Making data transfers faster) . What i want is probaly in between letter class a and g. http://en.wikipedia.org/wiki/Wi-Fi_Technical_Information

[Your Amish Daddy]

Um, I was just asking if it was A. You don't have to be an assclown, I know how friggin' radio frequencies work. Here's a little tip that applies to anything that works with a radio frequency. Lower the range...Lower the broadcast power has to be to get the same coverage. That's why G has the longest range out of the fully-adopted instances of wireless.

[halo2_god]

Well, i wanst attempting to be an "assclown".I was only trying to tell you more indepth information. Also what i want doesnt have to have 5.0 GHz all i said is would be nice.

[cambrose]

1st off...don't use a usb adapter...they suck bigtime

Secondly, go for a pci card and just use that. I have a dlink WDA-2320 that works like a charm, plus it is an atheros card so it's compliant with linux out of the box if you ever want to experiment that way.

[halo2_god]

1st off...don't use a usb adapter...they suck bigtime

Secondly, go for a pci card and just use that. I have a dlink WDA-2320 that works like a charm, plus it is an atheros card so it's compliant with linux out of the box if you ever want to experiment that way.

Well im going to use it on a laptop and PC swich oh so often. I have a linux/unix boot disk wich i want it to be compatible with. my laptop built in chip is not that good (range wise i barly get a signal through like 1 wall). so thats why i wanted a usb device im not sure that my PC (dell) 5 years old is compatible with it. (I would use the pci cards but its just the compatiblity isue) also i use to have a linksys usb device with a usb router it was harible omg 11mbps but there where like 3 walls in the way.

[cambrose]

Does your laptop have a pcmia port? If so, I suggest getting that kind of card, as the usb adapter are generally pathetic. Also, a usb adapter should theoretically work with the old Dell you speak of as well (I had a computer that was running 98se using WiFi via a USB adapter)

[halo2_god]

Um, well my laptop is getting a new hardrive upgrade. so i dont have it but i know it has one of those slots to but a wifi card in the side. But what i mean is if i get a wifi pci card it wont work for my pc but it will work for my laptop and the usb will work for baoth.

[cambrose]

I understand that, I am just implying that they suck in general, but since you don't want to buy two adapters, that is probably your best bet. If you get one I suggest you get one that doesn't stick straight into the side of your pc but has a usb cord that you plug in and the actual transmitter you can place somewhere close via an attached cable.

[halo2_god]

I understand that, I am just implying that they suck in general, but since you don't want to buy two adapters, that is probably your best bet. If you get one I suggest you get one that doesn't stick straight into the side of your pc but has a usb cord that you plug in and the actual transmitter you can place somewhere close via an attached cable.

oh i see what you mean could you show me one so i could know what they look like brb getting an orange.

[cambrose]

http://www.newegg.com/Product/Product.aspx?Item=N82E16833315075
http://www.newegg.com/Product/Product.aspx?Item=N82E16833124158

and I know this is a PCI card but if you could find something similar in USB you'd be set...
http://www.newegg.com/Product/Product.aspx?Item=N82E16833315041

[halo2_god]

Sorry to take so long... But i use to have the linksys one i dont know if its the same thing but it was harrible. i think it was like 11MBPS

[cambrose]

11mbps would be B wireless, the G one would perform considerably better.

[halo2_god]

I found this as wilreless-N http://www.bestbuy.com/site/olspage.jsp?skuId=8305602&type=product&id=1173577562601 and at this link it seys realeas date 2009 http://en.wikipedia.org/wiki/Wi-Fi_Technical_Information

[cambrose]

If you don't have an n router, that won't do you any good. Secondly, the N stuff that is out now is technically not standard n and isn't guaranteed to work when the official version comes out in '09.

[halo2_god]

Oh, and how much do you think a 3.7 GHz intena is? one that would give me a good 150 meters.?

[cambrose]

Could you give me a link at what you are looking at? Please note, using third party antennas often breaks FCC regulations in regard to your wifi...just so you know.

[halo2_god]

I dont know where i would look i think newegg.com would sell them. I'm looking for one right now. Umm, http://www.newegg.com/Product/Product.aspx?Item=N82E16833997009 mabey

[Your Amish Daddy]

Another radio lesson...You can use any non-powered antenna for any broadcast range, which is why you need an FCC license to broadcast at over a watt. Why don't you stick with what's tried and true instead of trying to get into a range you may or may not be able to get into with the devices and ranges you're talking about?

Also, how are you going to use 802.11y when there are no devices for it yet? If you're going to do a longshot and want the best signal, get two decent wireless cards, I recommend dlink cards, and use cantennas.

[halo2_god]

Umm, I lost you there lol. idk know that much about radio frequencys but that looked like the only antenna that would work.

[Your Amish Daddy]

I'm saying that any antenna, designed for A or Y or N or B or G, will work across the spectrum. Hell, a wire ran up a steel pole and soldered the shield to the bottom and the carrier to the top. The best design for long shot is a cantenna, or a dish antenna.

[halo2_god]

What does a cantenna look like?

[Your Amish Daddy]

Google it. I may be Your Amish Daddy, but I'm not gonna hold your hand.

[DogDragon]

http://www.turnpoint.net/wireless/cantennahowto.html

[halo2_god]

Could any one show me a wifi device (USB) aroud 50 - 60 dollars from best buy or around 30 dollars from something like newegg.com, radio shack ect... I Want one with long range atleast 100 feet and atleast 54MBPS i also want it to have WEP if you can find one that supports WPA for like 10-15 dollars more show me.

[airbornflght]

Umm...

Ok, first.

Wireless devices that I know of in the consumer market are operating in the 2.4Ghz(b/g) and the 5Ghz(a) bandwidths.

Now what you may have been looking at with those antennas is the attenuation, which is given in Db/m, I think. It basically describes how focused the waves are. If I remember correctly the larger the number the more focused the signal and the further the distance will be. But the narrower the spread. For instance a parabolic reflector would most likely have a high attenuation.

Also, changing the antenna will not break fcc regulations as far as I'm aware. Antennas do not change the power of the radio (which is goverened by fcc regulations) it merely shapes the signal differently. I know there is a regulation on the signal density or something of another, but as far as I know, even with a parabolic reflector the signal won't be dense enough to do any damage even if you were right on top of the antenna. Another side note, I highly doubt the fcc is honestly going to care about using an illegal antenna. Quite honestly, until you start interfering with other radio communications you won't even be noticed.

The range is going to be affected by your surrounding. In a vast nothingness the range can be up to a km if I remember correctly. But in a house with walls the range will vary depending on the construction. ferrite (I think) metals suck up radio frequencies like it's nobody's business. Another sidenote is that 802.11G's theoretical max throughput is 54 megabits per second. or 54 million bits per second. that is 6.75 million bytes or 6.75 megabytes per second. But again this is a theoretical limit and the hardware of the unit is going to affect maximum throughput. From what I've read real world throughput is somewhere around 3-5MB/s Which is more than enough for anything you should be doing, just don't expect to shuttle large files back and forth at speed with this connection.

Again, I am by no means an expert, but I know enough to be dangerous:D I may have used some incorrect terminology.

[Your Amish Daddy]

Ok, you're almost 100% right. The FCC can arrest you for the manufacture of nonstandard broadcasting equipment. I believe this includes antennas that can leak a signal. And unoriginal name guy, you're asking one hell of a wireless card to shoot 100 feet at 54mbit. Even with a parabolic antenna, you'd still only do about 60 feet with it at 54mbit because wireless cards and routers have a limit on their broadcasting power; the strongest ever being around 100mW.

What I don't understand is; is why the FCC police a free spectrum. It's not like friggin' MICROWAVES aren't already a breech of the FCC broadcasting terms, because they DO broadcast a signal at 2.4ghz, even if it's not intentional.

[airbornflght]

It has to do with consumer laws. I'm guess that you are talking about microwave broadcasting. Commercial places can buy a license for that area and frequency.

If you're talking about an actual microwave oven, those should be shielded because of an fcc regulation that says it can't emit any rf interference.

The only reason I can guess that the fcc has regulation is so that the spectrum does remain open. If I had a megawatt wifi signal no one within probably 100 miles would be able to use wifi equipment because my signal would overrun theirs on the channel my radio was set to. The main reason I'm guessing we don't see more powerful radios in wifi equipment is cost.

[Your Amish Daddy]

Please, I've got a 16 watt powered CB antenna that would take me next to nothing to rig up for my wireless card. The thing is, the FCC states that no one can broadcast over a watt because they're a bunch of rectum rangers. Their excuse is what you said, to prevent interference with other devices, but microwaves do leak signal, the kind of signal that disables wifi (2.4ghz range).

Sure the FCC doesn't go trolling around looking for this stuff, but it only takes a phonecall and then huge fines or jailtime. If this isn't for a laptop, just run some cat5/6 and be done with it. 100/1000mbit is better than wireless anyway.

[kryyst]

Could any one show me a wifi device (USB) aroud 50 - 60 dollars from best buy or around 30 dollars from something like newegg.com, radio shack ect... I Want one with long range atleast 100 feet and atleast 54MBPS i also want it to have WEP if you can find one that supports WPA for like 10-15 dollars more show me.

Any new off the shelf 54g router will do what you want.

[the_technocrat]

Could any one show me a wifi device (USB) aroud 50 - 60 dollars from best buy or around 30 dollars from something like newegg.com, radio shack ect... I Want one with long range atleast 100 feet and atleast 54MBPS i also want it to have WEP if you can find one that supports WPA for like 10-15 dollars more show me.

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&Description=usb%20802%2E11g&bop=And&Order=PRICE

[the_technocrat]

Any new off the shelf 54g router will do what you want.

That's a good point as well, you could easily wire the metal shelf found in most retail stores up to the antenna's BNC connector and have a high-gain antenna.

[Buddy J]

http://www.newegg.com/Product/Product.aspx?Item=N82E16833164012

Look, it's a dish!

[the_technocrat]

http://www.newegg.com/Product/Product.aspx?Item=N82E16833164012

Look, it's a dish!

That's not a dish, that's a parabolic antenna.

The parabolic antenna is a high-gain reflector antenna used for radio, television and data communications, and also for radiolocation (RADAR), on the UHF and SHF parts of the electromagnetic spectrum. The relatively short wavelength of electromagnetic (radio) energy at these frequencies allows reasonably sized reflectors to exhibit the very desirable highly directional response for both receiving and transmitting.
Parabolic antennas at the Very Large Array Radio Telescope in New Mexico, USA
Parabolic antennas at the Very Large Array Radio Telescope in New Mexico, USA

A typical parabolic antenna consists of a parabolic reflector illuminated by a small feed antenna.

The reflector is a metallic surface formed into a paraboloid of revolution and (usually) truncated in a circular rim that forms the diameter of the antenna. This paraboloid possesses a distinct focal point by virtue of having the reflective property of parabolas in that a point light source at this focus produces a parallel light beam aligned with the axis of revolution.

The feed antenna is placed at the reflector focus. This antenna is typically a low-gain type such as a half-wave dipole or a small waveguide horn. In more complex designs, such as the Cassegrain antenna, a sub-reflector is used to direct the energy into the parabolic reflector from a feed antenna located away from the primary focal point. The feed antenna is connected to the associated radio-frequency (RF) transmitting or receiving equipment by means of a coaxial cable transmission line or hollow waveguide.
Main types of parabolic antennas
Main types of parabolic antennas

Considering the parabolic antenna as a circular aperture gives the following approximation for the maximum gain:

G\approx (\pi^2 D^2)/\lambda^2\,

or

G\approx (9.87D^2)/\lambda^2\,

where:

G \,\! is power gain over isotropic
D \,\! is reflector diameter in same units as wavelength
\lambda \,\! is wavelength

Practical considerations of antenna effective area and sidelobe suppression reduce the actual gain obtained to between 35 and 55 percent of this theoretical value. For theoretical considerations of mutual interference (at frequencies between 2 and c. 30 GHz - typically in the Fixed Satellite Service) where specific antenna performance has not been defined, a reference antenna based on Recommendation ITU-R S.465 is used to calculate the interference, which will include the likely sidelobes for off-axis effects.

Applying the formula to just one of the 25-meter-diameter VLA antennas shown in the illustration for a wavelength of 21 cm (1.42 GHz, a common radio astronomy frequency) yields an approximate maximum gain of 140,000 times or about 50 dBi (decibels above the isotropic level).

With the advent of TVRO and DBS satellite television, the parabolic antenna became a ubiquitous feature of urban, suburban, and even rural, landscapes. Extensive terrestrial microwave links, such as those between cellphone base stations, and wireless WAN/LAN applications have also proliferated this antenna type. Earlier applications included ground-based and airborne radar and radio astronomy. The largest "dish" antenna in the world is the radio telescope at Arecibo, PR, but, for beam-steering reasons, it is actually a spherical, rather than parabolic, reflector.
Contents
[hide]

* 1 Structure
* 2 Feeding parabolic antennas.
* 3 See also
* 4 External links

[edit] Structure

The reflector dish can be solid, mesh or wire in construction and it can be either fully circular or somewhat rectangular depending on the radiation pattern of the feeding element. Solid antennas have more ideal characteristics but are troublesome because of weight and high wind load. Mesh and wire types weigh less, are easier to construct and have nearly ideal characteristics if the holes or gaps are kept under 1/10 of the wavelength.
Wire-type parabolic antenna (Wi-Fi / WLAN antenna at 2,4Ghz). Oriented to provide horizontal polarization: the reflector wires and the feed element are both horizontal. This antenna has a greater extent in the vertical plane and hence, a narrower beamwidth in that plane. The feed element has a wider beam in the vertical direction than the horizontal and hence matches the reflector by illuminating it fully.
Wire-type parabolic antenna (Wi-Fi / WLAN antenna at 2,4Ghz). Oriented to provide horizontal polarization: the reflector wires and the feed element are both horizontal. This antenna has a greater extent in the vertical plane and hence, a narrower beamwidth in that plane. The feed element has a wider beam in the vertical direction than the horizontal and hence matches the reflector by illuminating it fully.

More exotic types include the off-set parabolic antenna, Gregorian and Cassegrain types. In the off-set, the feed element is still located at the focal point, which because of the angles utilized, is usually located below the reflector so that the feed element and support do not interfere with the the main beam. This also allows for easier maintenance of the feed, but is usually only found in smaller antennas.

The Gregorian and Cassegrain types, sometimes generically referred to as "dual optics" antennas, utilize a secondary reflector, or "sub-reflector", allowing for better control over the colimnated beam as well as allowing the antenna feed system to be more compact. These antennas are usually much larger where prime focus and off-set construction are not as practical. The feed element is usually located in a "feed horn" which protrudes out from the main reflector. This setup is used when the feed element is bulky or heavy such as when it contains a pre-amplifier or even the actual receiver or transmitter. Parabolic antenna theory closely follows optics theory. So a Gregorian antenna can be identified by the fact that it uses a concave sub-reflector, while a Cassegrain antenna uses a convex sub-reflector.

Antenna feeders

The actual 'antenna' in a parabolic antenna, that is, the device that interfaces the transmission line or waveguide containing the radio-frequency energy to free space, is the feed element. The reflector surface is entirely passive. This feed element should usually be at the center of the reflector at the focal point of that dish. The focal point is the point where all reflected waves will be concentrated. The focal length f (distance of focal point from the center of the reflector) is calculated with the following equation:

f = \frac{D^2}{16d}


where:

f \,\! is the focal length of the reflector
D \,\! is reflector diameter in same units as wavelength
d \,\! is depth of the reflector

The radiation from the feed element induces a current flow in the conductive reflector surface which, in turn, re-radiates in the desired direction, perpendicular to the directrix plane of the paraboloid. The feed element can be any one of a multitude of antenna types. Whichever type is used, it must exhibit a directivity that efficiently illuminates the reflector and must have the correct polarization for the application -- the polarization of the feed determining the polarization of the entire antenna system. The simplest feed is a half-wave dipole which is commonly used at lower frequencies, sometimes in conjunction with a closely coupled parasitic reflector or "splash plate". At higher frequencies a horn-type becomes more feasible and efficient. To adapt the horn to a coaxial antenna cable, a length of waveguide is used to effect the transition.

[the_technocrat]

Analytic geometry equations

In Cartesian coordinates, a parabola with an axis parallel to the y\,\! axis with vertex (h, k)\,\!, focus (h, k + p)\,\!, and directrix y = k - p\,\!, with p\,\! being the distance from the vertex to the focus, has the equation with axis parallel to the y-axis

(x - h)^2 = 4p(y - k) \,

or, alternatively with axis parallel to the x-axis

(y - k)^2 = 4p(x - h) \,

More generally, a parabola is a curve in the Cartesian plane defined by an irreducible equation of the form

A x^2 + B xy + C y^2 + D x + E y + F = 0 \,

such that B^2 = 4 AC \,, where all of the coefficients are real, where A \not= 0 \, or C \not= 0 \,, and where more than one solution, defining a pair of points (x, y) on the parabola, exists. That the equation is irreducible means it does not factor as a product of two not necessarily distinct linear equations.

[edit] Other geometric definitions
Parabolas are conic sections.
Parabolas are conic sections.

A parabola may also be characterized as a conic section with an eccentricity of 1. As a consequence of this, all parabolas are similar. A parabola can also be obtained as the limit of a sequence of ellipses where one focus is kept fixed as the other is allowed to move arbitrarily far away in one direction. In this sense, a parabola may be considered an ellipse that has one focus at infinity. The parabola is an inverse transform of a cardioid.

A parabola has a single axis of reflective symmetry, which passes through its focus and is perpendicular to its directrix. The point of intersection of this axis and the parabola is called the vertex. A parabola spun about this axis in three dimensions traces out a shape known as a paraboloid of revolution.

The parabola is found in numerous situations in the physical world (see below).

[edit] Equations

(with vertex (h, k) and distance p between vertex and focus - note that if the vertex is below the focus, or equivalently above the directrix, p is positive, otherwise p is negative; similarly with horizontal axis of symmetry p is positive if vertex is to the left of the focus, or equivalently to the right of the directrix)

[edit] Cartesian

[edit] Vertical axis of symmetry

(x - h)^2 = 4p(y - k) \,

y = a(x-h)^2 + k \,

y = ax^2 + bx + c \,

\mbox{where }a = \frac{1}{4p}; \ \ b = \frac{-h}{2p}; \ \ c = \frac{h^2}{4p} + k; \ \
h = \frac{-b}{2a}; \ \ k = \frac{4ac - b^2}{4a}.

x(t) = 2pt + h; \ \ y(t) = pt^2 + k \,

[edit] Horizontal axis of symmetry

(y - k)^2 = 4p(x - h) \,

x = a(y - k)^2 + h \,

x = ay^2 + by + c \,

\mbox{where }a = \frac{1}{4p}; \ \ b = \frac{-k}{2p}; \ \ c = \frac{k^2}{4p} + h; \ \
h = \frac{4ac - b^2}{4a}; \ \ k = \frac{-b}{2a}.

x(t) = pt^2 + h; \ \ y(t) = 2pt + k \,

[edit] Semi-latus rectum and polar coordinates

In polar coordinates, a parabola with the focus at the origin and the directrix on the positive x-axis, is given by the equation

r (1 + \cos \theta) = l \,

where l is the semilatus rectum: the distance from the focus to the parabola itself, measured along a line perpendicular to the axis. Note that this is twice the distance from the focus to the apex of the parabola or the perpendicular distance from the focus to the latus rectum.

[edit] Gauss-mapped form

A Gauss-mapped form: (tan2φ,2tanφ) has normal (cosφ,sinφ).

[edit] Derivation of the focus
Parabolic curve showing directrix (L) and focus (F). The distance from a given point Pn to the focus is always the same as the distance from Pn to a point Qn directly below, on the directrix.
Parabolic curve showing directrix (L) and focus (F). The distance from a given point Pn to the focus is always the same as the distance from Pn to a point Qn directly below, on the directrix.

Given a parabola parallel to the y-axis with vertex (0,0) and with equation

y = a x^2, \qquad \qquad \qquad (1)

then there is a point (0,f) — the focus — such that any point P on the parabola will be equidistant from both the focus and a line perpendicular to the axis of symmetry of the parabola (the linea directrix), in this case parallel to the x axis. Since the vertex is one of the possible points P, it follows that the linea directrix passes through the point (0,-f). So for any point P=(x,y), it will be equidistant from (0,f) and (x,-f). It is desired to find the value of f which has this property.

Let F denote the focus, and let Q denote the point at (x,-f). Line FP has the same length as line QP.

\| FP \| = \sqrt{ x^2 + (y - f)^2 },
\| QP \| = y + f.
\| FP \| = \| QP \|
\sqrt{x^2 + (a x^2 - f)^2 } = a x^2 + f \qquad

Square both sides,

x^2 + (a x^2 - f)^2 = (a x^2 + f)^2 \qquad

= a^2 x^4 + f^2 + 2 a x^2 f \quad

x^2 + a^2 x^4 + f^2 - 2 a x^2 f = a^2 x^4 + f^2 + 2 a x^2 f \quad

Cancel out terms from both sides,

x^2 - 2 a x^2 f = 2 a x^2 f, \quad
x^2 = 4 a x^2 f. \quad

Cancel out the x² from both sides (x is generally not zero),

1 = 4 a f \quad
f = {1 \over 4 a }

Now let p=f and the equation for the parabola becomes

x^2 = 4 p y \quad

Q.E.D.

All this was for a parabola centered at the origin. For any generalized parabola, with its equation given in the standard form

y = ax2 + bx + c,

the focus is located at the point

\left (\frac{-b}{2a},\frac{-b^2}{4a}+c+\frac{1}{4a} \right)

and the directrix is designated by the equation

y=\frac{-b^2}{4a}+c-\frac{1}{4a}

[edit] Reflective property of the tangent

The tangent of the parabola described by equation (1) has slope

{dy \over dx} = 2 a x = {2 y \over x}

This line intersects the y-axis at the point (0,-y) = (0, - a x²), and the x-axis at the point (x/2,0). Let this point be called G. Point G is also the midpoint of points F and Q:

F = (0,f), \quad
Q = (x,-f), \quad
{F + Q \over 2} = {(0,f) + (x,-f) \over 2} = {(x,0) \over 2} = ({x \over 2}, 0).

Since G is the midpoint of line FQ, this means that

\| FG \| \cong \| GQ \|,

and it is already known that P is equidistant from both F and Q:

\| PF \| \cong \| PQ \|,

and, thirdly, line GP is equal to itself, therefore:

\Delta FGP \cong \Delta QGP

It follows that \angle FPG \cong \angle GPQ .

Line QP can be extended beyond P to some point T, and line GP can be extended beyond P to some point R. Then \angle RPT and \angle GPQ are vertical, so they are equal (congruent). But \angle GPQ is equal to \angle FPG . Therefore \angle RPT is equal to \angle FPG .

The line RG is tangent to the parabola at P, so any light beam bouncing off point P will behave as if line RG were a mirror and it were bouncing off that mirror.

Let a light beam travel down the vertical line TP and bounce off from P. The beam's angle of inclination from the mirror is \angle RPT , so when it bounces off, its angle of inclination must be equal to \angle RPT . But \angle FPG has been shown to be equal to \angle RPT . Therefore the beam bounces off along the line FP: directly towards the focus.

Conclusion: Any light beam moving vertically downwards in the concavity of the parabola (parallel to the axis of symmetry) will bounce off the parabola moving directly towards the focus. (See parabolic reflector.)

[edit] What happens to a parabola when "b" varies?

Vertex of a parabola: Finding the y-coordinate

We know the x-coordinate at the vertex is x=-\frac{b}{2a}, so substitute it into the equation ax2 + bx + c

y=a\left (-\frac{b}{2a}\right )^2 + b \left ( -\frac{b}{2a} \right ) + c\qquad\textrm{Then~simplify\ldots}
=\frac{ab^2}{4a^2} -\frac{b^2}{2a} + c
=\frac{b^2}{4a} -\frac{2\cdot b^2}{2\cdot 2a} + c\cdot\frac{4a}{4a}
=\frac{-b^2+4ac}{4a}
=-\frac{b^2-4ac}{4a}=-\frac{D}{4a}

Thus, the vertex is at point…

\left (-\frac{b}{2a},-\frac{D}{4a}\right )

[edit] Parabolas in the physical world
A bouncing ball captured with a stroboscopic flash at 25 images per second. Note that the ball becomes significantly non-spherical after each bounce, especially after the first. That, along with spin and air resistance, causes the curve swept out to deviate slightly from the expected perfect parabola
A bouncing ball captured with a stroboscopic flash at 25 images per second. Note that the ball becomes significantly non-spherical after each bounce, especially after the first. That, along with spin and air resistance, causes the curve swept out to deviate slightly from the expected perfect parabola

In nature, approximations of parabolas and paraboloids are found in many diverse situations. The most well-known instance of the parabola in the history of physics is the trajectory of a particle or body in motion under the influence of a uniform gravitational field without air resistance (for instance, a baseball flying through the air, neglecting air friction). The parabolic trajectory of projectiles was discovered experimentally by Galileo in the early 17th century, who performed experiments with balls rolling on inclined planes. The parabolic shape for projectiles was later proven mathematically by Isaac Newton. For objects extended in space, such as a diver jumping from a diving board, the object itself follows a complex motion as it rotates, but the center of mass of the object nevertheless forms a parabola. As in all cases in the physical world, the trajectory is always an approximation of a parabola. The presence of air resistance, for example, always distorts the shape, although at low speeds, the shape is a good approximation of a parabola. At higher speeds, such as in ballistics, the shape is highly distorted and does not resemble a parabola.
Parabolic shape formed by the surface of a Newtonian liquid under rotation
Parabolic shape formed by the surface of a Newtonian liquid under rotation

Another situation in which parabola may arise in nature is in two-body orbits, for example, of a small planetoid or other object under the influence of the gravitation of the sun. Such parabolic orbits are a special case that are rarely found in nature. Orbits that form a hyperbola or an ellipse are much more common. In fact, the parabolic orbit is the borderline case between those two types of orbit. An object following a parabolic orbit moves at the exact escape velocity of the object it is orbiting, while elliptical orbits are slower and hyperbolic orbits are faster.

Approximations of parabolas are also found in the shape of cables of suspension bridges. Freely hanging cables do not describe parabolas, but rather catenary curves. Under the influence of a uniform load (for example, the deck of bridge), however, the cable is deformed toward a parabola.

Paraboloids arise in several physical situations as well. The most well-known instance is the parabolic reflector, which is a mirror or similar reflective device that concentrates light or other forms of electromagnetic radiation to a common focal point. The principle of the parabolic reflector may have been discovered in the 3rd century BC by the geometer Archimedes, who, according to a legend of debatable veracity,[1] constructed parabolic mirrors to defend Syracuse against the Roman fleet, by concentrating the sun's rays to set fire to the decks of the Roman ships. The principle was applied to telescopes in the 17th century. Today, paraboloid reflectors can be commonly observed throughout much of the world in microwave and satellite dish antennas.

Paraboloids are also observed in the surface of a liquid confined to a container and rotated around the central axis. In this case, the centrifugal force causes the liquid to climb the walls of the container, forming a parabolic surface. This is the principle behind the liquid mirror telescope.

Aircraft used to create a weightless state for purposes of experimentation, such as NASA's “vomit comet,” follow a vertically parabolic trajectory for brief periods in order to trace the course of an object in free fall, which produces the same effect as zero gravity for most purposes.

[Buddy J]

Analytic geometry equations

In Cartesian coordinates, a parabola with an axis parallel to the y\,\! axis with vertex (h, k)\,\!, focus (h, k + p)\,\!, and directrix y = k - p\,\!, with p\,\! being the distance from the vertex to the focus, has the equation with axis parallel to the y-axis

(x - h)^2 = 4p(y - k) \,

or, alternatively with axis parallel to the x-axis

(y - k)^2 = 4p(x - h) \,

More generally, a parabola is a curve in the Cartesian plane defined by an irreducible equation of the form

A x^2 + B xy + C y^2 + D x + E y + F = 0 \,

such that B^2 = 4 AC \,, where all of the coefficients are real, where A \not= 0 \, or C \not= 0 \,, and where more than one solution, defining a pair of points (x, y) on the parabola, exists. That the equation is irreducible means it does not factor as a product of two not necessarily distinct linear equations.

[edit] Other geometric definitions
Parabolas are conic sections.
Parabolas are conic sections.

A parabola may also be characterized as a conic section with an eccentricity of 1. As a consequence of this, all parabolas are similar. A parabola can also be obtained as the limit of a sequence of ellipses where one focus is kept fixed as the other is allowed to move arbitrarily far away in one direction. In this sense, a parabola may be considered an ellipse that has one focus at infinity. The parabola is an inverse transform of a cardioid.

A parabola has a single axis of reflective symmetry, which passes through its focus and is perpendicular to its directrix. The point of intersection of this axis and the parabola is called the vertex. A parabola spun about this axis in three dimensions traces out a shape known as a paraboloid of revolution.

The parabola is found in numerous situations in the physical world (see below).

[edit] Equations

(with vertex (h, k) and distance p between vertex and focus - note that if the vertex is below the focus, or equivalently above the directrix, p is positive, otherwise p is negative; similarly with horizontal axis of symmetry p is positive if vertex is to the left of the focus, or equivalently to the right of the directrix)

[edit] Cartesian

[edit] Vertical axis of symmetry

(x - h)^2 = 4p(y - k) \,

y = a(x-h)^2 + k \,

y = ax^2 + bx + c \,

\mbox{where }a = \frac{1}{4p}; \ \ b = \frac{-h}{2p}; \ \ c = \frac{h^2}{4p} + k; \ \
h = \frac{-b}{2a}; \ \ k = \frac{4ac - b^2}{4a}.

x(t) = 2pt + h; \ \ y(t) = pt^2 + k \,

[edit] Horizontal axis of symmetry

(y - k)^2 = 4p(x - h) \,

x = a(y - k)^2 + h \,

x = ay^2 + by + c \,

\mbox{where }a = \frac{1}{4p}; \ \ b = \frac{-k}{2p}; \ \ c = \frac{k^2}{4p} + h; \ \
h = \frac{4ac - b^2}{4a}; \ \ k = \frac{-b}{2a}.

x(t) = pt^2 + h; \ \ y(t) = 2pt + k \,

[edit] Semi-latus rectum and polar coordinates

In polar coordinates, a parabola with the focus at the origin and the directrix on the positive x-axis, is given by the equation

r (1 + \cos \theta) = l \,

where l is the semilatus rectum: the distance from the focus to the parabola itself, measured along a line perpendicular to the axis. Note that this is twice the distance from the focus to the apex of the parabola or the perpendicular distance from the focus to the latus rectum.

[edit] Gauss-mapped form

A Gauss-mapped form: (tan2φ,2tanφ) has normal (cosφ,sinφ).

[edit] Derivation of the focus
Parabolic curve showing directrix (L) and focus (F). The distance from a given point Pn to the focus is always the same as the distance from Pn to a point Qn directly below, on the directrix.
Parabolic curve showing directrix (L) and focus (F). The distance from a given point Pn to the focus is always the same as the distance from Pn to a point Qn directly below, on the directrix.

Given a parabola parallel to the y-axis with vertex (0,0) and with equation

y = a x^2, \qquad \qquad \qquad (1)

then there is a point (0,f) — the focus — such that any point P on the parabola will be equidistant from both the focus and a line perpendicular to the axis of symmetry of the parabola (the linea directrix), in this case parallel to the x axis. Since the vertex is one of the possible points P, it follows that the linea directrix passes through the point (0,-f). So for any point P=(x,y), it will be equidistant from (0,f) and (x,-f). It is desired to find the value of f which has this property.

Let F denote the focus, and let Q denote the point at (x,-f). Line FP has the same length as line QP.

\| FP \| = \sqrt{ x^2 + (y - f)^2 },
\| QP \| = y + f.
\| FP \| = \| QP \|
\sqrt{x^2 + (a x^2 - f)^2 } = a x^2 + f \qquad

Square both sides,

x^2 + (a x^2 - f)^2 = (a x^2 + f)^2 \qquad

= a^2 x^4 + f^2 + 2 a x^2 f \quad

x^2 + a^2 x^4 + f^2 - 2 a x^2 f = a^2 x^4 + f^2 + 2 a x^2 f \quad

Cancel out terms from both sides,

x^2 - 2 a x^2 f = 2 a x^2 f, \quad
x^2 = 4 a x^2 f. \quad

Cancel out the x² from both sides (x is generally not zero),

1 = 4 a f \quad
f = {1 \over 4 a }

Now let p=f and the equation for the parabola becomes

x^2 = 4 p y \quad

Q.E.D.

All this was for a parabola centered at the origin. For any generalized parabola, with its equation given in the standard form

y = ax2 + bx + c,

the focus is located at the point

\left (\frac{-b}{2a},\frac{-b^2}{4a}+c+\frac{1}{4a} \right)

and the directrix is designated by the equation

y=\frac{-b^2}{4a}+c-\frac{1}{4a}

[edit] Reflective property of the tangent

The tangent of the parabola described by equation (1) has slope

{dy \over dx} = 2 a x = {2 y \over x}

This line intersects the y-axis at the point (0,-y) = (0, - a x²), and the x-axis at the point (x/2,0). Let this point be called G. Point G is also the midpoint of points F and Q:

F = (0,f), \quad
Q = (x,-f), \quad
{F + Q \over 2} = {(0,f) + (x,-f) \over 2} = {(x,0) \over 2} = ({x \over 2}, 0).

Since G is the midpoint of line FQ, this means that

\| FG \| \cong \| GQ \|,

and it is already known that P is equidistant from both F and Q:

\| PF \| \cong \| PQ \|,

and, thirdly, line GP is equal to itself, therefore:

\Delta FGP \cong \Delta QGP

It follows that \angle FPG \cong \angle GPQ .

Line QP can be extended beyond P to some point T, and line GP can be extended beyond P to some point R. Then \angle RPT and \angle GPQ are vertical, so they are equal (congruent). But \angle GPQ is equal to \angle FPG . Therefore \angle RPT is equal to \angle FPG .

The line RG is tangent to the parabola at P, so any light beam bouncing off point P will behave as if line RG were a mirror and it were bouncing off that mirror.

Let a light beam travel down the vertical line TP and bounce off from P. The beam's angle of inclination from the mirror is \angle RPT , so when it bounces off, its angle of inclination must be equal to \angle RPT . But \angle FPG has been shown to be equal to \angle RPT . Therefore the beam bounces off along the line FP: directly towards the focus.

Conclusion: Any light beam moving vertically downwards in the concavity of the parabola (parallel to the axis of symmetry) will bounce off the parabola moving directly towards the focus. (See parabolic reflector.)

[edit] What happens to a parabola when "b" varies?

Vertex of a parabola: Finding the y-coordinate

We know the x-coordinate at the vertex is x=-\frac{b}{2a}, so substitute it into the equation ax2 + bx + c

y=a\left (-\frac{b}{2a}\right )^2 + b \left ( -\frac{b}{2a} \right ) + c\qquad\textrm{Then~simplify\ldots}
=\frac{ab^2}{4a^2} -\frac{b^2}{2a} + c
=\frac{b^2}{4a} -\frac{2\cdot b^2}{2\cdot 2a} + c\cdot\frac{4a}{4a}
=\frac{-b^2+4ac}{4a}
=-\frac{b^2-4ac}{4a}=-\frac{D}{4a}

Thus, the vertex is at point…

\left (-\frac{b}{2a},-\frac{D}{4a}\right )

[edit] Parabolas in the physical world
A bouncing ball captured with a stroboscopic flash at 25 images per second. Note that the ball becomes significantly non-spherical after each bounce, especially after the first. That, along with spin and air resistance, causes the curve swept out to deviate slightly from the expected perfect parabola
A bouncing ball captured with a stroboscopic flash at 25 images per second. Note that the ball becomes significantly non-spherical after each bounce, especially after the first. That, along with spin and air resistance, causes the curve swept out to deviate slightly from the expected perfect parabola

In nature, approximations of parabolas and paraboloids are found in many diverse situations. The most well-known instance of the parabola in the history of physics is the trajectory of a particle or body in motion under the influence of a uniform gravitational field without air resistance (for instance, a baseball flying through the air, neglecting air friction). The parabolic trajectory of projectiles was discovered experimentally by Galileo in the early 17th century, who performed experiments with balls rolling on inclined planes. The parabolic shape for projectiles was later proven mathematically by Isaac Newton. For objects extended in space, such as a diver jumping from a diving board, the object itself follows a complex motion as it rotates, but the center of mass of the object nevertheless forms a parabola. As in all cases in the physical world, the trajectory is always an approximation of a parabola. The presence of air resistance, for example, always distorts the shape, although at low speeds, the shape is a good approximation of a parabola. At higher speeds, such as in ballistics, the shape is highly distorted and does not resemble a parabola.
Parabolic shape formed by the surface of a Newtonian liquid under rotation
Parabolic shape formed by the surface of a Newtonian liquid under rotation

Another situation in which parabola may arise in nature is in two-body orbits, for example, of a small planetoid or other object under the influence of the gravitation of the sun. Such parabolic orbits are a special case that are rarely found in nature. Orbits that form a hyperbola or an ellipse are much more common. In fact, the parabolic orbit is the borderline case between those two types of orbit. An object following a parabolic orbit moves at the exact escape velocity of the object it is orbiting, while elliptical orbits are slower and hyperbolic orbits are faster.

Approximations of parabolas are also found in the shape of cables of suspension bridges. Freely hanging cables do not describe parabolas, but rather catenary curves. Under the influence of a uniform load (for example, the deck of bridge), however, the cable is deformed toward a parabola.

Paraboloids arise in several physical situations as well. The most well-known instance is the parabolic reflector, which is a mirror or similar reflective device that concentrates light or other forms of electromagnetic radiation to a common focal point. The principle of the parabolic reflector may have been discovered in the 3rd century BC by the geometer Archimedes, who, according to a legend of debatable veracity,[1] constructed parabolic mirrors to defend Syracuse against the Roman fleet, by concentrating the sun's rays to set fire to the decks of the Roman ships. The principle was applied to telescopes in the 17th century. Today, paraboloid reflectors can be commonly observed throughout much of the world in microwave and satellite dish antennas.

Paraboloids are also observed in the surface of a liquid confined to a container and rotated around the central axis. In this case, the centrifugal force causes the liquid to climb the walls of the container, forming a parabolic surface. This is the principle behind the liquid mirror telescope.

Aircraft used to create a weightless state for purposes of experimentation, such as NASA's “vomit comet,” follow a vertically parabolic trajectory for brief periods in order to trace the course of an object in free fall, which produces the same effect as zero gravity for most purposes.

TT is right, but I think what he's forgetting and what would really fix your problem is to just get an isotropic radiator from Radio Shack. They should have a USB 2.0 model for under $50.

[the_technocrat]

No he's looking for a WIRELESS antenna, and besides, you can run Cat5e up a central HVAC's intake vent, not in a heated water pipe, you sill knob-tobbler!

[the_technocrat]

although an isotropic radiator is a good idea. Hold on, I have to go get a drink of water, brb

[Thrax]

If you attach a shoelace to your wifi card you should get an awesome signal but a narrow projection of signal. It reminds me of the one time I attached my cell phone to a can of progresso soup and a sock and got over 9000 bars and the FCC came and were all like "what what" and I was like. :( also because its super easy if you made your own parabolic superantenna out of aluminum foil.

DON'T HARASS ME I KNOW WHAT I'M FRIGGIN DOING GRRRRRRRANGRYGRRRRRRRR

http://icrontic.com/forum/attachment.php?attachmentid=24458&stc=1&d=1197573381

ASSCLOWNS

[the_technocrat]

OK, so anyway, you'd have to find a solution to the Hairy Ball Theorem (http://en.wikipedia.org/wiki/Hairy_ball_theorem)to get the radiator to put out a wireless signal. Not a bad idea at all, and I think Radio Shack sells an adapter. Although it's one of those crappy adapter where its one common end and you have to bring your radiator in to find the end that fits yours, etc.

[the_technocrat]

DON'T HARASS ME I KNOW WHAT I'M FRIGGIN DOING GRRRRRRRANGRYGRRRRRRRR

http://icrontic.com/forum/attachment.php?attachmentid=24458&stc=1&d=1197573381

ASSCLOWNS

Obviously you do not. The nonuniform consistency of progresso soup will BLOCK any signal instead of AMPLIFYING it. Any first-year EE or art major can tell you that. If you had gone with a more traditional, non-facist soup like Cream of Tomato, you wouldn't have gotten caught.

[the_technocrat]

AND ANOTHER THING oops caps I don't appreciate being called names. you have no idea who i am. I've never met you. You weren't there when I was molested at the circus, so you couldn't possibly KNOW WHAT I AM oops caps going through!!!11!

and I have more to say but I have to go make some soup, THANKS A LOT

[Buddy J]

<object width="638" height="533"><param name="movie" value="http://www.youtube.com/v/XbgvvzVvNSI&rel=1&autoplay=1"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/XbgvvzVvNSI&rel=1&autoplay=1" type="application/x-shockwave-flash" wmode="transparent" width="638" height="533"></embed></object>

[the_technocrat]

<object width="638" height="533"><param name="movie" value="http://www.youtube.com/v/XbgvvzVvNSI&rel=1&autoplay=1"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/XbgvvzVvNSI&rel=1&autoplay=1" type="application/x-shockwave-flash" wmode="transparent" width="638" height="533"></embed></object>

see, i told you it works, look, you can see the signal going in right there.

[Thrax]

http://icrontic.com/forum/attachment.php?attachmentid=12669&d=1098763559

[GrayFox]

When did Icrontic turn into 4chan ......

edit: Might as well get with the flow.

http://www.poolsclosed.org/images/PoolsClosed.jpg

edit: Just noticed theres 2 pages before this.

[the_technocrat]

This is a discussion about wireless. What does that have to do with a pool? Unless you're talking about a pool of leasable IP addresses, in which case, yes, it should be closed with some sort of MAC filtering. ???

[Thrax]

noob you can mac spoof and get in np. If you use Cain & Abel you can sniff the MAC over wifi. I hate morons like you.

[GrayFox]

noob you can mac spoof and get in np. If you use Cain & Abel you can sniff the MAC over wifi. I hate morons like you.
I thought you could only do this on linux and windows drivers are too crippled ?. (Wouldn't surprise me if Cain's dev team figured it out tho).

The Cain & Abel development team are always doing more and more things that scare me with how easy they make it. I remember when cracking wep at a reasonable speed required linux/bsd/mac os......

[the_technocrat]

noob you can mac spoof and get in np. If you use Cain & Abel you can sniff the MAC over wifi. I hate morons like you.

you're right! (/subscription to internet)

I used to know this gay friend of mine that could explain about the plenum cable, I'll try to get him on here.

[primesuspect]

No he's looking for a WIRELESS antenna, and besides, you can run Cat5e up a central HVAC's intake vent, not in a heated water pipe, you sill knob-tobbler!

You have to be sure to use Plenum Cat5E when running network cable through any forced-air ductwork.

PVC (or Polyvinyl Chloride), which is illustrated here:


http://www.lenntech.com/images/PVC_formula.gif

Has a few characteristics which make it a code violation to install through any ductwork, notably toxic fumes being given off during combustion. Being that PVC is a thermoplastic material, it is much more flexible however.

Plenum, while having negative traits such as higher difficulty of crimping, stripping, and less flexibility is nonetheless safer (and sometimes the only legal choice) to use when installing cable through ductwork.

Plenum can be made with a variety of materials - DuPont Teflon is a commonly used one. It is important to note that "Plenum" is not a material or form of construction, but a rating based on the cable's ability to be used in the "plenum space" of commercial and residential construction projects that include space for HVAC ducting.

In an interesting bit of controversy, in 2006, significant concern developed over the potential toxicity of FEP and related fluorochemicals used in the construction of jacketing rated "plenum". The NFPA Technical Committee on Air Conditioning, in response to public comment, has referred the issue of toxicity of cabling materials to the NFPA Committee on Toxicity for review before 2008.

[the_technocrat]

oh hi!

[primesuspect]

Christ. Worst timing EVER.

[Lincoln]

HAHAHhahaha. OMG. Brian just looked up from his computer with this horrified/laughing face and sputters "oh my god! oh man! I just owned myself BAD!" ;D ;D ;D

[primesuspect]

We couldn't have coordinated that if we had tried.

[Thrax]

this is srs thread, brian is srs

[primesuspect]

WAITAMINNIT

I see what you did there. My hat's off to you, sir. Well played.

[Lincoln]

No wait! It's even better! TT edited his post AFTER Brian posted, making him THINK he had owned HIMSELF. Hahahaha.

[Buddy J]

hilarity ensues

[the_technocrat]

pwnd

[halo2_god]

OMFG what is happening im asking a simple question and people are now saying mathmatical eqatuions for some **** that im soooooo lost. All i want is a USB device that has good speed and long range. supports WPA, WEP. Jesus.............. Why are people showing math equations how is that going to help me deicde what USB wifi device to get. (Also i said i wanted to change the antenna to have a higher GHz to like 3.7 or 3.2 instead of the average 2.4 GHz)

[Thrax]

Buy any 802.11G USB adapter.

You can't change the frequency.

The end.

[the_technocrat]

<object width="309" height="58"><param name="movie" value="http://embed.grandcentral.com/flash/GC_EmbedPlayer.swf?e=a6a7048a353d2c983c4c3&m=2d734980a6d10f3377bda8353bc61c06"></param><param name="wmode" value="transparent"></param><embed src="http://embed.grandcentral.com/flash/GC_EmbedPlayer.swf?e=a6a7048a353d2c983c4c3&m=2d734980a6d10f3377bda8353bc61c06" type="application/x-shockwave-flash" wmode="transparent" width="309" height="58"></embed></object>

<3 u Prime

[fatcat]

;D ;D ;D

:kneel:

[halo2_god]

OK, Thank you but does any one know which is the best to buy from bestbuy 60 dollars and less.

[the_technocrat]

Don't hijack the thread!

[Buddy J]

Srsly. Go start your own. (http://www.bestbuy.com/site/olspage.jsp?skuId=8454638&type=product&id=1184369369644)

[Thelemech]

http://www.bestbuy.ca/catalog/proddetail.asp?sku_id=0926INGFS10056425&catid=21120&logon=&langid=EN

is this what you are looking for?

[halo2_god]

http://www.bestbuy.ca/catalog/proddetail.asp?sku_id=0926INGFS10056425&catid=21120&logon=&langid=EN

is this what you are looking for?

Yeah but i belive the turbo mode only works on other D-link routers and what the range on it.

[GrayFox]

"Turbo mode" Is just broadcom's afterburner, It should work on any hardware that supports it.

[Buddy J]

The one I linked to is better because it has a real antenna and is made by Hawking.

http://www.bestbuy.com/site/olspage.jsp?skuId=8454638&type=product&id=1184369369644

[GHoosdum]

This thread replaces the cat thing as my favorite from yesterday.

[Thelemech]

it has a real antenna


You call that a real antenna ... this my friend is what he needs...:tongue:

[the_technocrat]

how do they shoot lightning from it like that!

[mas0n]

how do they shoot lightning from it like that!

It's hooked up to a normal pci adapter, they just upped the jigawatts.

[Thrax]

That's my CN antenna. It's not content to receive a signal, so it goes out and gets the signal its f'ing self with <i>real lightning</i>.

[Thelemech]

That's my CN antenna. It's not content to receive a signal, so it goes out and gets the signal its f'ing self with real lightning.

Precisely!:cool2: ...and it's USB 2.0 friendly...

[the_technocrat]

well I think we found the solution this thread is looking for: a consumer-grade wireless access point that has its power turned up to interplanetary-communications level. Simple enough.

edit: I forgot that we also need to turn the hardwired components up to 40 billihurtz to up the transfer rate

[Thrax]

<embed src="http://www.youtube.com/v/EqDZc5GA9es&autoplay=1&rel=0&color1=0x006699&color2=0x54abd6&border=0" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed>

[the_technocrat]

<embed src="http://www.youtube.com/v/EqDZc5GA9es&autoplay=1&rel=0&color1=0x006699&color2=0x54abd6&border=0" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed>

this is the worst explanation of Hairy Ball theorem I've ever heard.

[Buddy J]

Building a life size antenna similar to this should take care of all your signal problems too. Obviously the can used in it is a 500 gallon one, seeing as it's bigger than the guys constructing it. I think that for your limited range requirement, an institutional size of nacho cheese can (#10 industrial size) would work so long as your wifi card could push out 10mA at 11hz

<object width="425" height="355"><param name="movie" value="http://www.youtube.com/v/hNFKbcJ_WK8&rel=1&autoplay=1"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/hNFKbcJ_WK8&rel=1&autoplay=1" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed></object>

[halo2_god]

WTF ^ to the post above me ^ Also one other thing could some one fine me a good 30 - 40 dollar USB wifi device from www.newegg.com because im no where at all good with this kind of stuff. lol

[Thrax]

Buy anything in that price range and it will work just fine, as I said 20 posts ago.

[Buddy J]

This will work (http://www.newegg.com/Product/Product.aspx?Item=N82E16833315075) and you should be able to hook your cantenna up to it brb gotta take a dump k

[halo2_god]

OK, thanks for all the help but what would be the best to buy from say, bestbuy, newegg, radioshack, jr.com, circuitcity, or sears these are the places i can name of the top of my head. ps the reason im asking this question and im not checking my self is because your the pros right :)

[Buddy J]

I'd buy from newegg because they support Icrontic bbiab gotta beat a dead horse.

[halo2_god]

What does that mean? lol

[halo2_god]

Umm is this any good its like 10 dollars from newegg and also it seys 80 feet out door 60 indoors http://www.newegg.com/Product/Product.aspx?Item=N82E16833180017

[Buddy J]

I thought you wanted to spend more than $10?

[halo2_god]

yeah i do im just saying lol so cheep for a damn good range.

[halo2_god]

http://www.newegg.com/Product/Product.aspx?Item=N82E16833315075 one person said this is good for wardriving and thats one perpose i want it for :) would this be good?

[primesuspect]

http://icrontic.com/images/prime/sai_says_stop.jpg

[the_technocrat]

http://www.newegg.com/Product/Product.aspx?Item=N82E16833315075 one person said this is good for wardriving and thats one perpose i want it for :) would this be good?

I think you're looking to go 'ghostriding'.

[halo2_god]

Hmmm never heard of that befor. <(ghosttriding)

[Buddy J]

Thizz face wid ya stunna shadez on son.

The ones you are looking at are too small. Spend the money and get the one I linked to. It's your best bet.

[NiGHTS]

This thread is better than sex.

[Thelemech]

http://icrontic.com/images/prime/sai_says_stop.jpg



;D;D;D;D;D;D;D


Buy anything in that price range and it will work just fine, as I said 20 posts ago.


:bigggrin::bigggrin::bigggrin::bigggrin::bigggrin::bigggrin::bigggrin:

[GHoosdum]

Hmmm never heard of that befor. <(ghosttriding)

It's when you drive around in your car just cruisin' for some wifi, then you stick the throttle, jam the steering wheel to one side and jump out and ride the car.

Also, it's this (http://imdb.com/title/tt0259324/).

[Thelemech]

Yes, just think halo2_god this could be You {of course with a very long usb chord attached to the antenna with the lightning power I posted earlier to the bike handlebars; also you could add the can project that BuddyJesus posted to the front of the bike

[Thrax]

DID SOMEONE SAY GHOSTRIDE?

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[the_technocrat]

I prefer this fate for every ghostrider:

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