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3 mile wireless range

Discussion in 'Networking Issues' started by sillyreefer, May 12, 2005.

  1. sillyreefer

    sillyreefer LI Guru Member

    I have been contemplating, and researching this for 3 months now. Basically I want to be able to access my wireless network at home while I am at school, which is about 2.5 miles away. THe reason for that is because I dont have internet access at my college. What exactly is Dbi, and how do you know the range for them? Also, the only wireless routers I have right now are BEFW11S4, and I hate them. Any recommendations along with a good omni directional (This is the kind of antennat I need for my setup) antenna to use for that range?
  2. Guyfromhe

    Guyfromhe Network Guru Member

    you can't get an omni that will go that far from linksys, you'd need a really serious antenna and some extreme power boosting to get that without LOS, you'd probably also need a fairly large tower... you could do it with directional antennas with LOS but I don't think you'd going to pull off what you need with what you have...
  3. J_Man61

    J_Man61 LI Guru Member

    dBi is a ratio, measured in decibels, of the effective gain of an antenna compared to an isotropic antenna. The greater the dBi value, the higher the gain and, as such, the more acute the angle of coverage.
  4. gotamd

    gotamd LI Guru Member

    I don't think that's a realistic goal.
  5. XCOM7

    XCOM7 LI Guru Member

    It is possible if you have a wireles hop in between.
  6. jagboy

    jagboy Network Guru Member

    couldnt he mount one ap with some serious cantennas and then point them at the college. and crank up the power. :D but you might need a wrt54g for this
  7. sillyreefer

    sillyreefer LI Guru Member

    Ok if I have a directional, that means that there isn't a radius of coverage, but more in the direction of where it is going? The antenna would have good line of site if it is mounted on top of the roof which is what I am doing. I know the router I have right now, for one just plain sucks, and I dont think it could shove out that much power. Then again I am not guite sure. I guess what I am trying to say is my ultimate goal, within a year or two, would be to set up a community wireless network (since it is pretty much unheard of in central minnesota, aside from home wireless networks), with the only income coming from donations and my own pocket. But for now I just want to accomplish one thing, and that is to hop on my wireless network at home from the college. Are there any recommendations on websites for different antennas?
  8. jagboy

    jagboy Network Guru Member

    there is no firmware for the router that you have right now that will crank up the power. but i would go with the wrt54g. throw some antennas and some dd-wrt pre 4 firmware and call it a day. this is what i would do but this is not coast effective.
  9. windsurfer

    windsurfer LI Guru Member

    With 802.11B you can get a mile with two can antenna's. 802.11G is stronger but I doubt you can get 3 miles.

    Here is a page that has some nice antenna listed:

    http://www.hyperlinktech.com/web/wifi_grid_antennas.php

    If you want 3 miles you will need one of these on each end and they will be connected to something solid as the wind likes to blow them around some.

    I would choose the 24db model as that will give you extra signal for wet days when the world is a sponge for wifi.

    Use something like netstumbler to check to see they are pointed correctly.

    Good Luck
  10. TazUk

    TazUk Network Guru Member

    You would of course need these antennas at both ends ;)
  11. Guyfromhe

    Guyfromhe Network Guru Member

    aren't cantena's directional? I think (from his post) he wants to be able to wander around campus 3 miles away with a laptop not setup a fixed wireless link to the school...
  12. windsurfer

    windsurfer LI Guru Member

    A can antenna is fairly directional but not like one of the dish type antennas.

    Take a look at the NEC model of the pattern coming out of a can antenna.

    http://www.ivor.it/wireless/cantenna.html

    This is one of the best pictures I have ever seen for a can antenna.
  13. gotamd

    gotamd LI Guru Member

    Yeah, this is the problem. Without some kind of receiving station set up with an omni-directional repeater, this seems like it would be worthless. I doubt the college would agree to something like that, however, and the equipment needed would probably be pretty expenisve (the antennas and the mounting equipment). I mean, yes, you can do it. I just don't think it's reasonable for someone on a college-student budget.
  14. Guyfromhe

    Guyfromhe Network Guru Member

    plus it would be illegal, there are limits on power output on the 2.4 gig band..
  15. jagboy

    jagboy Network Guru Member

    forget the rules!!!
  16. Guyfromhe

    Guyfromhe Network Guru Member

    go tell that to the FCC
  17. jagboy

    jagboy Network Guru Member

    maybe you should consider the rules then..
  18. aaronamd

    aaronamd LI Guru Member

    I am not one to put a damper on things but isn't 2.4 ghz the same spectrum as water? guess what 80% of the body is made of? water. if you over-expose your eyes to 2.4 you can go blind. 2.4 is gamma radiation spectrum, which can cook you, therefore the limits are very neccessary.
  19. windsurfer

    windsurfer LI Guru Member

    2.4GHZ is also the frequency of many microwaves. You need to think about what you are doing. The following dish has a note that says stay away 12 feet from the front. You can see the warning sign but the print is too small to read.

    http://windsurf.mediaforte.com/dish_can.jpg
  20. aaronamd

    aaronamd LI Guru Member

    I'm glad I'm not only one whos about 2.4 ghz. I had some freinds get very sick due to radiation overdose.....not from 2.4 but still..... they'r doing well now though!
  21. Guest

    Guest Guest

    Yes, it can be done. I have a two mile link up running two WAP54Gs
    with two BBQ dish antennas. I have a direct line of sight to my WISP.
    The signal is stong and I can do a flood ping with 0% packet loss.
    I also have a 15 mile link up using a WRT54G at my end, a 6 foor dish at
    the other end and a BBQ antenna here. I only get 1MB out of this setup.
    I also get a lot of packet loss.

    Don't try uping the power, all you will do is burn up the radio. The secret
    is in the antenna systems. Using short coax cables, tower mounted
    radios. Do some simple calculation to see how biroad your signal willl be.
    Check the beam widght of the antennas you get and plot that on a map.
    You must have line of sight!

    You don't want an Omni antenna for a link. They are good for an AP,
    say at you school, but that would require another radio.

    Good luck.
  22. jagboy

    jagboy Network Guru Member

    what kind of radiation from a microwave? nuclear power plant?
  23. aaronamd

    aaronamd LI Guru Member

    they were dumb and took the sheilding off a magnatron in a microwave and turned it on forgetting that what they took off was the sheilding....
  24. gotamd

    gotamd LI Guru Member

    Ouch, zapped human != good.
  25. Morpheus

    Morpheus Network Guru Member

    :lol: :lol: :lol: :lol:
  26. sillyreefer

    sillyreefer LI Guru Member

    Ok, now things are starting to become a little clear. I am going to purchase a WRT54G and upgrade the firmware with something that is available from wifi box. Anyway, I do understand the implications using just one antenna and try to beam it 3 miles away. Trying to get access right now at the college isn't my #1 goal right now, but it is one of them. I want to start an organization here in my city, since no one has even contemplated setting up a free large wifi network. I have a few questions though. One, I am probably going to have two wireless routers in my house. One access point would be for my normal house network, the second access point (WRT54G) would be for the community network. How would I go about connecting the routers but yet create two separate networks? Is that possible? Two, how many people can I really support. Now I know that access points (some of them anyway) can support a max of 100 wireless devices, but what I am wondering is how many people would it take to make the network really slow with a 1.5mbs high speed connection? Another questions that I have been pondering is can people add to the bandwidth with their own internet if they choose to? When I make my first link to my neighbor who is baffled by the idea of free wifi, ho would they set up their router to communicate with mine? Sorry for all the questions but I am confused.
  27. aaronamd

    aaronamd LI Guru Member

    at 1.5 mbits per secound it would take 11.5777 users to make it slow(ISDN speed or 128kbits per secound)so yah....
    ---------------------------------------------------
    yes people can to the bandwidth with their own connections but it will be more difficult to setup.
    ---------------------------------------------------
    if your neighbor owns a WRT54G then he can upload the latest Hyper WRT firmware and make a WDS connection to you, then enter your WRT54G mac address in his WDS screen and enter his in yours
  28. Guest

    Guest Guest

    I hate to say it but this is not rocket science. People just try to
    make it harder than it needs to be, The WRT54Gs are great
    little boxes. They are very flexiable with the right firmware.

    It may help you to see what I have put together:
    http://www.mt-umunhum-wireless.net/Images/Network-topology.png

    Not sure why you want two subnets, but you do so just configure
    your two router with different IP addresses. The second one
    will point to the first as a gateway. Both routers will be APs.
    I am assuming you will be putting up an external antenna for the
    second AP(?). Make sure you have seperation with the channel
    numbers of the two APs.

    If you draw a picture of what you want to do, it would be easier to
    help you configure the APs. The AP configurations can be very
    simple or very complex, that will be up to you. You should connect
    the two APs with a hardwired link ( hub to hub ).

    Anyway, the best teacher is just doing it. Good luck.

    .
  29. ChipW

    ChipW LI Guru Member

    I come here looking for help with one router issue I'm having (and apparently it's not router specific) and run into a subject I'm currently getting ready to work on.

    A friend of mine is located about 11 miles from me (Line of sight, 15 miles by drive distance) and in an area where broadband or even high speed modem is not available to him.... We are in the works of setting up a WiFi link between each other...

    We have found a directional antenna that will give us 22 db gain and claims 10mb between us up to 10 miles.... So we figure there will be a loss of about 2 or 3 mb which is fine.... This is done with some homebrew antennas using old Dish Network or DirecTV antennas.

    http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html

    We are also planning to use 2.4 GHz 1w amplifiers to help boost our power output.

    As far as the power output allowed by the FCC, you are running in the same band as FRS which is allowed 2 watts by the general public. Obtain a GMRS license and bump yourself to 5 watts. Since antennas would need to be very high to achive 'line of sight', the radiation put out even at 5 watts would be harmless to anyone in the path of the signal. For that matter, it would be harmless for anyone if it was at ground level... If it wasn't harmless, you wouldn't be allowed to obtain 5w GMRS radios.

    Sorry about the ramblings, but this just happens to be a subject that I'm going to be dealing with once I obtain all the needed componants...

    Chip
  30. Guest

    Guest Guest

    Two quick comments:
    1) You will need a dish antenna at both ends of the link.
    2) Do not use an amp, it is illegal and will cause problems for others
    near you. You will getting into a power war! Not good for anyone.
    William

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