when we use horizental /vertical antenna in wireless & why?
108576
It has to do with horizontal and vertical lines of magnetic propogation, and it also deals with the way that EMI fields of energy will dissipate from an antanae when a volatage is applied through it.\n\nBasically you will use different shaped antenna to get better RF coverage to certain areas.
79854
YOU HAVE TO BE WITHIN A CERTAIN RANGE OF A CELL TOWER. IF YOU ARE TOO MANY MILES AWAY, YOU WILL NOT HAVE A SIGNAL.  MANY PEOPLE THAT LIVE OUT IN THE COUNTRY CAN'T EVEN USE CELL PHONES/
84634
probably there are service providers in your area that can offer you WiFi connections across those 10kms with no complexity.\nIf you are trying to do it by yourself, you will need microwave antenas aligned in a careful way at every point which you want to provide conectivity and repeaters, so wireless users can detect those signals
11421
Yes !    --   The card you have installed matters the most and I'm hoping it has an external antenna jack.  (is there a short, stubby, rubber, doo-hicky sticking out of the back of your pc.  If so that's it--      Visit this websitehttp://www.turnpoint.net/wireless/cantennahowto.html and learn about a home-built solution to your question.  I made one and got a 9db gain (It triple the signal).   The 'Cantenna' works !! \n\nIf you don't have an antenna jack visible you can find info on how to disassemble the wireless card and how to modify it (getting techie extreme here..but hey, if it don't work now it ain't gonna hurt trying to rig it !!)See http://www.stanford.edu/group/denny/wireless.htm for insight to reverse engineering your card--
774184
A very good, complicated and interesting question.  Katy brought up a good point.  You could write entire book on how cell phones has changed daily life around the world.  Just think of how many business decisions are now done in real time rather than getting to a land line (telephone.)  Or how about a reporter in the field giving a story before he or she has set up the equipment to broadcast the story?  Or how about the reporting of the Iraq war where no broadcasting equipment was even available?  With cell phones, many of which now have cameras built into them, people are taking pictures of crimes as they occur.   This is also true for reporting crimes in areas that didn’t normally have phone access.\n\nSince you didn’t speak of which wireless technology you were referring to I can only assume you are talking about all wireless technology so I will discuss some others here.\n\nIn the last few years wireless networking for home computing has really taken off.  It has become much more affordable and easier to configure for the average person.  Now here is where it gets interesting.   Many new laptops have the ability for you to use a wireless networking adapter in them or with them.  Some cities, including mine in Anaheim California, are going to make the whole city wireless!   They are going to install wireless Internet transmitters all over Anaheim so everyone has a wireless connection to the Internet.  Even people visiting from out of town can use the wireless system but they have to pay a small access fee.   Can you imagine driving across the county someday and being able to access the Internet right from your car?\n\n\nLet us not forget that the first wireless technology started with the radio.  Man discovered radio in the late 1800’s.  Radio technology grew in bits and pieces but by the turn of the century wireless communications had been established.  All wireless routers and wireless Internet communication uses radio waves to send the data.\n\n\nLet us not forget RADAR.  RADAR is an acronym for Radio Detection and Ranging\nand helped us win the world war II.  One of the first uses of Microwave technology was used in RADAR in the world war II also.  Most households now use Microwaves to cook food with so radio waves also help us heat things\n\n\nWhat about television transmission?  Isn’t that also wireless?  Although many people now use cable (because they have paid for premium channels) television is a wireless technology.\n\nAnd others:\n\nRadio transponders to find lost aircraft (also a transponder)\nLo Jack stolen automobile retrieval device (also a transponder)\nNavigation\n\nRadio Frequency Identification (RFID) (also a transponder)\nRadio Frequency Identification is a way to remotely receive data from RFID tags or transponders.  They are used on toll roads and even at Mc Donald’s to buy lunch with a swipe of a small device.  They are used soo much that this needs to be researched all by itself.\n\nWhat all wireless technologies have in common is that they are all based on Radio waves.  All of things that I have mentioned are based on Radio technology \n\n\nP.S.  I usually don’t cut and paste and if I do I will say that, that is what I am doing and explain where that information came from.  I like to read information from multiple information sources then put that information together in my own words while keeping the article technically and factually correct.  And as always, I will point to web sites or other information to prove that my information is factual.
114702
Your question is not clear.  Since it is in "networking", it is presumably about antennas for 802.11 wireless or bluetooth, which operates in the same band.\n\nFirst source:  effects of antenna, multipath, etc.\n\n"An antenna simply integrates (or adds up) the various signals directed towards it, with a weighting factor as a function of both propagation and polarization directions.\nDirectionality can change magnitude of multipath effect seen by radio by minimizing contribution of other paths, but does not change radio’s innate ability to handle a given multipath effect.\nDoes interact with circuitry and nearfield environment, changing performance (see 11-04-0675)"\n\nSecond source:\n\n"New world record for unamplified wireless networking!! \n125 miles!"
516754
You should open up the mini-pci compartment and see if there are antenna cables there--some laptops have them preinstalled. Otherwise, you'll probably have to stick with your PCMCIA card, because there aren't mini-pci wireless cards that don't need antennas as far as I know.
770731
Wireless devices for personal usage are not supposed to be powerful enough.  Also, going by the specs, it is not a personal network anyway.\n\nSo, you need clearances from the controlling organization to operate such a network first of all.\n\nSecondly, since you say it must be wireless, I would guess you need some sort of sattelite service.  I do not personally know how costly that would be.\n\nOnce you have frequency usage/transmission clearances and satellite availability, it should not be an issue to support 200 nodes at all.
964197
An antenna has no power in it.  It is a "passive" device.  The effectiveness of the antena depends upon it's phsyical characteristics and the first electronic amplifier it is connected to.\n\nAn antenna has a specific frequency that it is most effective in capturing.  That length is usually a multiple of the wavelenth of the target frequency.  Typically an antenna that is equal to 1 wavelength is the most effective.  But this is not practical at lower frequencies where the wavelength is very long.\n\nSo the coupling between the antenna and the first electronic amplifier is critical.  The technology is well established and therefore, you can purchase good antennas.  What is more important however is the physical location. Radio signals are interrupted or interferred with by buildings and landscape.  So having an antenna that is unobstructed is the best way to improve reception.  However you have to weigh the location against the distance to the radio or tv or other device, as this will cause signal loss over longer distances.
84334
See if your radio will take an external antenna.  If so, then grab some wire and string it around, and as high as you can.
146268
In the telephone network, the pair of wires that connects your phone directly to the nearest box(switch) is called the Local-loop (coz' it's a dedicated pair of wires local to your phone). It's also called the Last-mile. \n\nWhen a telephone operator swtiches to WLL, it essentially means that he repalced your box(switch, and end-point your and many of your neighbours telephone wires) with a Wireless switch. So now your phone would communicate with the switch not using a wire but through air. Rest of the network (beyond the box) is the same.\n\nThis essentially means that you can roam about with your WLL phone within the aerial range of that switch(which now becomes an antenna).\n\nOn the contrary, when, in a Mobile network, you move out of the range of your present antenna, another antenna picks you up. This the reason why WLL is also called a Limited Mobility Mobile system.
1029353
As others have answered, it's because the signal is passed from one "cell", or transmitting tower to another as you move.\n\nUp until the mid or late 80's, there were still mobile phones which were not cell phones.  These were basically just specialized radios, and had limited range.  They were expensive and limited to people like doctors and the wealthy.  I'm not sure when they finally phased them out, or even if they are still available somewhere, but as cell phones became more & more common, and the coverage got better, there was just no need for the old style mobile phones, and the two terms became synonymous.
703895
It is used to talk hands-free with your cell phone.\n\n(Notice my avitar has one)\n\nYou clip it to your ear and talk on your cell with it, without having to hold up your cell phone.\n\nSome are wireless some are not, it depends.\n\nHope this helps!
464881
Several options...\n\nYou can add a high-gain antenna to your router, if it has a detachable antenna type...\n\nYou can add a "Wireless access point" at a different location in the building...\n\nYou might consider re-locating your router...  perhaps it's in a shielded spot..\n\nYou can get a "repeater" which is connected through the building power wiring (though I've never actually tested one of these, and have my doubts about the bandwidth...)\n\nAn "amplifier"? No, because that would put your router outside the limits in the regulations - and probably do all kinds of horrid things to the signal. In addition, yo'd need one at each end of the link...\n\nYou could try a router with a MIMO adatptive antenna system, that might help.\n\nYou could also look at systems like Pre-N, which supposedly has a better range, though you'll need to replace all your devices with Pre-N compatible ones, to get the benefit.
634639
From Wikipedia:\n\n"The 802.16 specification applies across a wide swath of RF specrutm, but specification is not the same as permission to use. There is no uniform global licensed spectrum for WiMAX. In the US, the biggest segment available is around 2.5GHz, and is already assigned, primarily to Sprint Nextel. Elsewhere in the world, the most likely bands used will be around 3.5GHz, 2.3/2.5GHz, or 5GHz, with 2.3/2.5 GHz probably being most important in Asia.\n\n"There is some prospect that some of a 700MHz band might be made available for WiMAX use, but it is currently assigned to the analog TV and awaits the complete rollout of HD digital TV before it can become available, likely by 2009. And, in any case, there will be other uses suggested for that spectrum if and when it actually becomes open.\n\n"It seems likely that there will be several variants of 802.16, depending on local regulatory conditions and thus on which spectrum is used. Even if everything but the underlying radio frequencies is the same. WiMAX equipment will not, therefore, be as portable as it might have been. And perhaps even less so than WiFi, whose assigned channels in unlicensed spectrum varies more than a little from jurisdiction to jurisdiction."
400251
the signal applied to the antenna is in relation to groud. the signal spewed out by radio stations travels thru the air. and a very small signal is placed on the antenna in relation to the ground. the receiver circuit takes over from there. if you drive by a radio station you will see their big antenna very isolated from ground. to prevent arching. the signal coming from them is very powerful. \n\n                                  Greg..
650858
sometimes they are used for radio antennas