cantenna - Dish network dish ?

Discussion in 'Wireless Internet' started by Frank Dowling, May 6, 2004.

  1. probably a foolish question.
    would a regular Dish network or Direct TV satellite dish work as a cantenna
    for wireless b or g ?
     
    Frank Dowling, May 6, 2004
    #1
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  2. Frank Dowling

    zaphod Guest

    Of course it will. they showed some homemade antennas in TechTV using old
    dishes about three weeks ago. It achieved impressive results.
     
    zaphod, May 6, 2004
    #2
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  3. Frank Dowling

    dold Guest

    Odd that you should ask that. I'm going to put a D-Link USB DWL-122 onto a
    Dish-Dish tonight. Maybe I'll take pictures.
     
    dold, May 6, 2004
    #3
  4. First a couple of observations:

    "Cantenna" is the name of two distinct entities: Cantenna is the brand
    name of a commercial product which sells for about twenty bucks. It is a
    waveguide antenna which is designed for WiFi use.

    "Cantenna" is also a generic name for homemade WiFi antennas of various RF
    design specifications, which incorporate a metalic tin can, or other
    cylindrical shaped packaging materials. The actual materials used in
    these homemade designs have been limitted only by the user's ingenuity,
    and have included Snack Chip cans, (pringles being the perrenial favorite),
    Coffee cans, beef stew, etc.

    Much ado has been made of the use of DSS type satellite dishes for WiFi
    use. They can be made to work, but suffer from inherent drawbacks, like
    wind loading factors, poor driver to reflector coupling, etc.

    my personal feeling is that if a user wish to have a high gain, highly
    directional antenna, they can be purchased for very affordable prices, and
    the better designs don't suffer from the drawbacks mentioned.

    The primnary difficulty for the do-it-yourselfer, when using these DSS
    dishes is proper illumination of the dish, and RF coupling, from the
    driven element onto the reflector. The best designs I've seen, which are
    to be had from a judicious Googling, involve the "BiQuad" driver design.
    If you're NOT going to be using a BiQuad driver, I wouldn't bother wasting
    my time in this endeavor.



    vg
     
    =?iso-8859-1?q?Valent=EDn_Guill=E9n?=, May 6, 2004
    #4
  5. Would ordinary co-axial cable work ?
    Or should one use other types of cables ?
    how would reception compare to a "cantenna" ?
     
    Frank Dowling, May 6, 2004
    #5
  6. I just don't get it. 2.4GHz antennas are so cheap and so well made, why
    dick around with making your own? At the moment I have a 9dbi panel
    antenna (about 4-5 inches in each direction, about 1 inch thick) out on
    my porch connecting to an access point omni about a quarter mile away. I
    have excellent signal strength and link quality. Do you know how cheap
    these antennas are? If my time is worth $2/hr, then buying these panel
    antennas is a really good deal.
     
    =?ISO-8859-1?Q?R=F4g=EAr?=, May 6, 2004
    #6
  7. Rôgêr ,

    points well taken.
    just that I've got a handy Dish sitting on a tripod.
    what commercial antenna do you recommend ?
    also some "experts" contend that a home made antenna often will
    have better recepton than a commercial product.
    also what type of access point are you receiving ? how much
    strength is it putting out- i.e a commercial unit or just run of the
    mill wireless router .


    thanks
     
    Frank Dowling, May 6, 2004
    #7
  8. Frank Dowling

    mhicaoidh Guest

    Taking a moment's reflection, Valentín Guillén mused:
    |
    | my personal feeling is that if a user wish to have a high gain, highly
    | directional antenna, they can be purchased for very affordable prices, and
    | the better designs don't suffer from the drawbacks mentioned.

    Yeah, but the commercial stuff isn't as trick as the do-it-yourselfer
    stuff. ;-)
     
    mhicaoidh, May 6, 2004
    #8
  9. Frank Dowling wrote: Rôgêr ,

          points well taken.
          just that I've got a handy Dish sitting on a tripod.
          what commercial antenna do you recommend ?


    There are a whole slew of different antenna types which are available, depending upon your needs.   Directional types are good for higher gain needs, but have the disadvantage of needing precise aiming.  Omnis are good for wide-area coverage.  Flat panels are fairly directional, but have wider propagation  characteristics.  
          also some "experts" contend that a home made antenna often will
    have better recepton than a commercial product.
          also what type of access point are you receiving ?


    802.11b *cards* should connect with any brand of AP/router/etc. how much
    strength is it putting out- i.e a commercial unit or just run of the
    mill wireless router . Here are a couple of rinky-dink "dish-conversion" links, by people who didn't know better:

    http://www5.cs.cornell.edu/~eckstrom/802.11a/primestar/
    http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html

    Here's a good shot from a page of a guy who knows what he's doing:

    from this good "BiQuad" conversion page:  http://www.trevormarshall.com/biquad.htm

    And here's another shot from another European dish conversion page: 
    from here:  http://www.weijand.nl/wifi/

    Here's the commercial Cantenna from this page:  http://www.cantenna.com


    I'm partial to the Semi-Parabolic grid antennas, partially because of their extremely high gain characteristics, like this one:
        from this website:   http://www.wirelessinteractive.com

    I can connect to many wifi spots from my home with one of these, and some of those are miles away.   I connect to a wide variety of brands with one of these!

    And you're right......Many homemade antennas CAN often be very much better than commercial antennas, but invariably, these homemade jobs are constructed and designed by RF engineers, and they put a LOT of time and effort into them.   Don't be fooled!
     

    Regards,

    vg
     
     
     
    Valentin Guillen, May 6, 2004
    #9
  10. .... and similar garbage.

    Don't post HTML to newsgroups, and especially don't post broken html to
    them. Set your newsreader to post in plain text only.
     
    Mark McIntyre, May 6, 2004
    #10
  11. Frank Dowling wrote:

    Rôgêr ,

    points well taken.
    just that I've got a handy Dish sitting on a tripod.
    what commercial antenna do you recommend ?


    There are a whole slew of different antenna types which are available,
    depending upon your needs. Directional types are good for higher gain
    needs, but have
    the disadvantage of needing precise aiming. Omnis are good for
    wide-area coverage. Flat panels are fairly directional, but have wider
    propagation
    characteristics.


    also some "experts" contend that a home made antenna often will
    have better recepton than a commercial product.
    also what type of access point are you receiving ?


    802.11b *cards* should connect with any brand of AP/router/etc.

    how much
    strength is it putting out- i.e a commercial unit or just run of the
    mill wireless router .

    Here are a couple of rinky-dink "dish-conversion" links, by people who
    didn't know better:

    http://www5.cs.cornell.edu/~eckstrom/802.11a/primestar/
    http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html

    Here's a good shot from a page of a guy who knows what he's doing:
    http://www.trevormarshall.com/bq-soldering.jpg
    from this good "BiQuad" conversion page:
    http://www.trevormarshall.com/biquad.htm

    And here's another shot from another European dish conversion page:
    http://www.weijand.nl/wifi/index_files/image008.jpg
    from here: http://www.weijand.nl/wifi/

    Here's the commercial Cantenna from this page: http://www.cantenna.com
    http://www.cantenna.com/cantenna_images/canandpigtail03.jpg

    I'm partial to the Semi-Parabolic grid antennas, partially because of
    their extremely high gain characteristics, like this one:
    http://www.wirelessinteractive.com/images/Downloaded/WIDC24default_main.jpg
    from this website: http://www.wirelessinteractive.com

    I can connect to many wifi spots from my home with one of these, and
    some of those are miles away. I connect to a wide variety of brands
    with one of these!

    And you're right......Many homemade antennas CAN often be very much
    better than commercial antennas, but invariably, these homemade jobs are
    constructed and designed by RF engineers, and they put a LOT of time and
    effort into them. Don't be fooled!


    Regards,

    vg
     
    Valentin Guillen, May 7, 2004
    #11
  12. My antenna is a Maxrad WISP24009XF, runs about $26 + shipping. I don't
    mean that Maxrad is the only brand I'd use, it's just what I have at the
    moment. I've also used a couple of other antennas on this same setup and
    neither a 13dbi or a 19dbi performed any better.

    The access point is a commercial unit if that means you can't just walk
    into Walmart and buy one, and it's mounted outside. But it is unlicensed
    802.11b and it's not even putting out the maximum allowed by the FCC in
    terms of power - and it's on an 8 or 9dbi omni antenna. I *do* have
    clear line of sight.

    I also have another identical AP that's about a mile and half away that
    I can associate with at roughly the same signal strength and link
    quality as the one at a quarter mile. The only difference is it has a
    120° sector antenna instead of an omni. One other important fact,
    there's not much 2.4GHz pollution in my area, but that's changing month
    by month.
     
    =?ISO-8859-1?Q?R=F4g=EAr?=, May 7, 2004
    #12
  13. Just out of interest at what distance could a regular home wireless
    router be received by an antenna such as yours ?
     
    Frank Dowling, May 7, 2004
    #13
  14. Frank Dowling

    News Account Guest

    You have to buid a new feed - the Dish LNB is a 900MHz <-- 11-12GHz
    downconverter.

    Don Woodward
     
    News Account, May 7, 2004
    #14
  15. Frank Dowling

    dold Guest

    That has a dealer cost of $25.95, but a list of $51.99. Most of their
    other antennas are higher priced. Are you a dealer, or is the $26 a street
    price?
    My son threw away the Dish Network dish that I thought I was going to poach
    for my antenna.
    I was driving to work today with the DWL-122 usb-mini-wifi that I am going
    to use for my hobbyist antenna on the dashboard, running NetStumbler. 89
    APs in a 4 mile drive, 42 with WEP.

    A year ago, that wasn't true. There were maybe 10 on the same route.
     
    dold, May 8, 2004
    #15
  16. Frank Dowling

    Paul James Guest

    As for range on off the shelf products, I am using dlink 800+ access
    point to a Dlink 810+ ethernet bridge from well over a mile away with
    no problems, I also have several trees and bushes in the line of site
    and it doesn't seem to affect my signal all that much. The antennas I
    am using are 13dbi directional made by DB Performance (really just
    some 3" pvc pipes) I only use this connection for my ADSL link and it
    works great.
     
    Paul James, May 9, 2004
    #16
  17. Frank Dowling

    manuka Guest

    WiFi antenna, both commercial & DIY, may be "cheap " enough, but the
    low loss connectors & microwave cable can be VERY costly. Losses of
    1/2 dB a meter & 1dB a connector are typical even for US$5/m cable,&
    connectors need specialised $$$ crimping tools. You may have a
    tempting signal sweet spot say 10m (30') from your PC, but cabling to
    cover even that distance may cost US$50 & be lossy. ARGH !

    Off the shelf antenna in fact are often only modest performers for the
    price, & DIY gives the satisfaction of rustling up superior designs -
    especially if NetStumbler tuning/tweaking employed. Our 15-18 dB
    parabolic dish cost US$4 & anything comparable commercially would have
    been an order of magnitude more!

    As you may guess, my WiFi cabling experiences have lead to
    alternatives, such as POE (Power Over Ethernet).For DIY setups
    "masthead" USB greatly appeals & even the WiFi adaptors are cheap. See
    a "Poor Man's WiFi" educational project here in NZ =>
    www.usbwifi.orcon.net.nz
     
    manuka, May 9, 2004
    #17
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