Spherical pendulum - Revision history

en>Monkbot: Task 5: Fix CS1 deprecated coauthor parameter errors

2014-07-24T13:19:28Z

Task 5: Fix CS1 deprecated coauthor parameter errors

← Older revision		Revision as of 15:19, 24 July 2014
Line 1:		Line 1:
	~~In [[telecommunications]], particularly in [[radio]], '''signal strength''' refers to the [[magnitude (vector)\|magnitude]] of the [[electric field]] at a reference point that~~ is ~~a significant distance from the transmitting antenna. It may also be referred to as '''received signal level''' or '''field strength''~~'. ~~Typically, it is expressed in~~ [~~[voltage]~~] ~~per [[length]] or [[Transmitter power output\|signal power]] received~~ by ~~a reference antenna~~. [~~[Nominal power\|High-powered]] transmissions, such as those used in [[broadcasting]], are expressed in [[Decibel\|dB]]-[[millivolt]]s per metre (dBmV~~/m). ~~For very low-power systems, such as [[mobile phone]]s, signal strength is usually expressed in [[Decibel\|dB]]-[[microvolt]]s per metre (dBµV~~/~~m) or in [[decibel~~]~~]s above a reference level of one [[Watt (unit)\|milliwatt]] ([[dBm]])~~. ~~In broadcasting terminology, 1 mV~~/~~m is 1000 µV~~/~~m or 60 [[Decibel#Radio power, energy, and field strength\|dBµ]] (often written dBu)~~.		I am Consuelo and I love it. What me and my family members love is horse using but I'm considering on starting something new. Maryland has always been my house and my mothers and [http://Wordpress.org/search/fathers+reside fathers reside] close by. Taking care of animals is exactly where my [http://www.primaryearnings.org/ primary earnings] arrives from. I'm not good at webdesign but you might want to check my web site: https://wiki.lovefm.us/index.php?title=8_Strange_Facts_About_Nya_Internet_Svenska_Casino<br><br>

	~~;Examples:~~		My blog post [https://wiki.lovefm.us/index.php?title=8_Strange_Facts_About_Nya_Internet_Svenska_Casino nya online svenska casinon på nätet]
	*100 dBµ or 100 mV/m: [[blanketing]] interference may occur on some receivers
	*60 dBµ or 1.0 mV/m: frequently considered the edge of a [[radio station]]'s protected area in North America
	*40 dBµ or 0.1 mV/m: the minimum strength at which a station can be received with acceptable quality on most receivers

	~~==Relationship to average radiated power==~~

	The electric field strength at a specific point can be determined from the power delivered to the transmitting antenna, its geometry and radiation resistance. Consider the case of a center-fed half-wave [[dipole antenna]] in [[Free-space optical communication\|free space]], where the total length L is equal to one half wavelength (λ/2). If constructed from thin conductors, the current distribution is essentially sinusoidal and the radiating electric field is given by

	[~~[Image:lambdaover2-antenna.jpg\|frame\|Current distribution on antenna of length <math> \scriptstyle{L} </math> equal to one half wavelength (<math>\scriptstyle{\lambda /2}</math>).]]~~

	~~:<math>~~
	~~E_\theta (r) =~~
	~~{-jI_\circ\over 2\pi\varepsilon_\circ c\, r}~~
	~~{\cos\left(\scriptstyle{\pi\over 2}\cos\theta\right)\over\sin\theta}~~
	~~e^{j\left(\omega t-kr\right)}~~
	~~</math>~~

	where <math>\scriptstyle{\theta}</math> is the angle between the antenna axis and the vector to the observation point, <math>\scriptstyle{I_\circ}</math> is the peak current at the feed-point, <math>\scriptstyle{\varepsilon_\circ \, = \, 8.85\times 10^{-12} \, F/m }</math> is the permittivity of free-space, <math>\scriptstyle{c \, = \, 3\times 10^8 \, m/S}</math> is the speed of light in a vacuum, and <math>\scriptstyle{r}</math> is the distance to the antenna in meters. When the antenna is viewed broadside (<math>\scriptstyle{\theta \, = \, \pi/2}</math>) the electric field is maximum and given by
	~~:<math>~~
	~~\vert E_{\pi/2}(r) \vert = { I_\circ \over 2\pi\varepsilon_\circ c\, r }\, .~~
	~~</math>~~

	~~Solving this formula for the peak current yields~~

	~~:<math>~~
	~~I_\circ = 2\pi\varepsilon_\circ c \, r\vert E_{\pi/2}(r) \vert \, .~~
	~~</math>~~

	~~The average power to the antenna is~~

	:~~<math> {P_{avg} = {1 \over 2} R_a \, I_\circ^2 } </math>~~

	where <math> \scriptstyle{R_a = 73.13\,\Omega} </math> is the center-fed half-wave antenna’s radiation resistance. Substituting the formula for <math> \scriptstyle{I_\circ} </math> into the one for <math> \scriptstyle{P_{avg}} </math> and solving for the maximum electric field yields

	~~:<math>~~
	~~\vert E_{\pi/2}(r)\vert \, = \, {1 \over \pi\varepsilon_\circ c \, r}~~
	~~\sqrt{{ P_{avg} \over 2R_a}} \, = \,~~
	~~{9.91 \over r} \sqrt{ P_{avg} } \quad (L = \lambda /2) \, .~~
	~~</math>~~

	~~Therefore, if the average power to a half-wave dipole antenna is 1 mW, then the maximum electric field at 313 m (1027 ft) is 1 mV/m (60 dBµ).~~

	~~For a short dipole (<math>\scriptstyle{L \ll \lambda~~ /~~2}<~~/~~math>) the current distribution is nearly triangular~~. ~~In this case, the electric field and radiation resistance are~~

	~~:<math>~~
	~~E_\theta (r) =~~
	~~{-jI_\circ \sin (\theta) \over 4 \varepsilon_\circ c\, r} \left ( {L \over \lambda} \right )~~
	~~e^{j\left(\omega t-kr\right)} \, , \quad~~
	~~R_a = 20\pi^2 \left ( {L \over \lambda} \right )^2~~ .
	</~~math>~~

	~~Using a procedure similar to that above, the maximum electric field for a center-fed short dipole is~~

	~~:<math>~~
	~~\vert E_{\pi/2}(r)\vert \, = \, {1 \over \pi\varepsilon_\circ c \, r}~~
	~~\sqrt{{ P_{avg} \over 160}} \, = \,~~
	~~{9.48 \over r} \sqrt{ P_{avg} } \quad (L \ll \lambda /2)\,~~ .
	~~</math>~~

	=~~=Cellphone signals==~~
	~~{{main\|Mobile phone signal}}~~

	Although there are cell phone base station tower networks across many nations globally, there are still many areas within those nations that do not have good reception. Some rural areas are unlikely ever to be effectively covered since the cost of erecting a cell tower is too high for only a few customers. Even in high reception areas it is often found that basements and the interiors of large buildings have poor reception.

	Weak signal strength can also be caused by [[destructive interference]] of the signals from local towers in urban areas, or by the construction materials used in some buildings causing rapid attenuation of signal strength. Large buildings such as warehouses, hospitals and factories often have no usable signal further than a few metres from the outside walls.

	This is particularly true for the networks which operate at higher [[frequency]] since these are attenuated more rapidly by intervening obstacles, although they are able to use [[Reflection (physics)\|reflection]] and [[diffraction]] to circumvent obstacles.

	Cell phones in the U.S. operate at around 800 [[Hertz\|MHz]] and [[Personal Communications Service\|PCS phones]] at 1900 MHz, classified as [[UHF]] and low energy [[microwaves]] respectively. This has led to the rapid growth in the home [[cellular repeater]] market. The more advanced models now typically include an external [[directional antenna]] and an [[Linear amplifier\|amplifier]] (usually operating at 55 dB [[gain]]), which is generally enough to turn a very weak signal into a clear one over the local area (from around a thousand square feet to over twenty thousand).

	~~==See also==~~
	* [[Cel-Fi]]
	* [[Cell network]]
	* [[Cell phone]]
	* [[Cellular repeater]]
	* [[Dropped call]]
	* [[Dead zone (cell phone)]]
	* [[Received signal strength indication]]
	* [[S meter]]

	~~==References==~~
	~~{{Unreferenced\|date=December 2011}}~~
	~~{{reflist}}~~

	~~==External links==~~
	~~{{Refbegin}}~~
	* [http://www.opensignalmaps.com/ Global map of cell phone signal by network. Based on crowdsourced data.]
	* [http://openbmap.org/ Crowd sourced map of cell and wifi signals. Data release under the Open Database License.]
	~~{{Refend}}~~

	~~[[Category:Radio electronics]]~~
	~~[[Category:Mobile technology]]~~

	~~[[es:repetidor celular]]~~
	~~[[id:Penguat sinyal selular]~~]

en>Yobot: WP:CHECKWIKI error #52 fixed using AWB (9510)

2013-10-04T04:31:00Z

WP:CHECKWIKI error #52 fixed using AWB (9510)

Show changes

201.196.131.218 at 18:05, 11 March 2012

2012-03-11T18:05:35Z

New page

A lot of serious people are wondering in regards to the areas of consulting Magnetic Messaging in attaining focus of these friends and family. The simple fact we outlined right here compelled us to create a complete review on the shortcomings and benefits you may expect with all the provided dating guideline. It happens to be following complete researching and reliable screening that we have come up with the review you could genuinely financial institution on. Its a fairly proven fact that in the presence of a great deal of dating information programs that basically bust spot in the wallets to have you find yourself hunting for the dependable just one, we found Magnetic Messaging being worth getting reviewed. Right here now we have displayed various facets of Magnetic Messaging such as its cons, working and pros and our judgment that could be established on research and customer replies. 

Magnetic Messaging performs for the concepts of man mindset and makes use of the strategies that are known to have cause influences on human being thoughts. The best part of this dating system is that it do not include manipulation, its the ways of presenting your feelings that play the major role in bringing her towards you. If you have any concerns relating to wherever and how to use magnetic messaging reviews - [http://magneticmessagingbook.com Going in magneticmessagingbook.com],, you can make contact with us at the web-site. Magnetic Messaging holds in depth approaches and suggested texts for doing business all your family members in many different cases. The one of a kind highlights of the given courting guideline would be the comprehensive exercising training videos, 99 best text messages, magnetic mastermind equipment, and the virtual formatting the granted guideline is offered with. It might not, even so be, profitable using the ladies experiencing mental health issues relating to going out with and matrimony. During the light-weight of the aforementioned interactions, it can be very clear that positives exceed the cons and hence Magnetic Messaging is recommended on this page for anyone who actually feel short of words to express their emotions with their family in attractive method. Positives - Magnetic Messaging supports the crucial locking mechanism pattern that may be done in several techniques ; sending an emotionally charged text to prevent her in the capture and tracks her awareness, building an emotive exposure to her that is past the relaxed flirtation, and growing the craving of owning making love along with you. - The granted system will teach you to create your dialect to change a ice cold behaviour to the mental a single and lastly instilling longing for you. In this article learn how you can cram your textual content to give the best of your identity and acquire accessory towards you. - Here i will discuss because of the jokes and texts that were made to have her feel rigorous connection and interest inside you though arousing the romantic desire to be in actual association with you. - The various texts to eliminate reluctance and objections in her side have to date been valued by a great number of people. The initial reactions on the questions such as 'who are 'why and you' you wan to speak to me' are professed to get along with no failing price. - Setting up as a complete stranger and concluding with her inside an detailed relationship is precisely what Magnetic Messaging ideas and asserts you as a way to do. Gentle on the wallet, Magnetic Messaging is associated with 'The Infatuation Formula' to have girls mentally enslaved by be close to you, 'The Magnetic Mastermind Kit' with sophisticated strategies to rapid record seduction and also in depth training video analysis, and 'The 99 Finest Texts among all Time' to be utilized at different situations and occasions. - Magnetic Messaging is guaranteed with two months money back refund which reduces the possibility of the picture. Negatives - Magnetic Messaging is the effect of info gathered on man mindset and store procedures that happen to be expected to focus on common human imagination. It may possibly not function as correctly for females with slightly exclusive mind or physiological difficulties. - Obtaining Magnetic Messaging at some authentic supplier is critical to stay away from scam. - Employing Magnetic Messaging just for manipulation is not really motivated. Magnetic Messaging features the renowned 'key secure sequence' and assert you could pump motor your lover brimming withcuriosity and intrigue, and prefer to thumb and pickup in a very concept in her cell phone. This writer of Magnetic Messaging assertions that using three text messages, you can activate and awake an exciting and sexual area of her that you may not have access to had the opportunity to view until recently.