Minimizing antenna lead loss

Archived from groups: alt.internet.wireless (More info?)

Hi,

I am setting up a couple of antennas to connect 2 buildings about 300 feet
apart. I have discussed this with several people and a subject that came up
was antenna lead loss. One person said it was a big issue, and another says
it is nothing to worry about. Can anyone give me the straight scoop? BTW,
my antennas will be on roof tops, so I need enough lead length to get inside
to the access points.

Thanks,

Jerry
13 answers Last reply
More about minimizing antenna lead loss
  1. Archived from groups: alt.internet.wireless (More info?)

    Real Big Losses per foot
    what cable are you using - somebody will tell you loss per ft quickly

    I ordered a Cisco 15db Yaggi and part of the package included pre-made 50'
    belden RG8u which takes away 10db right off the bat not counting connectors
    ;) surely wont do much good. Good thing I got a deal otherwise I would
    have been upset if I knowingly paid for that cable.

    "JerryK" <jerryk.nospam@nospam.com> wrote in message
    news:41802fa5$1_1@127.0.0.1...
    > Hi,
    >
    > I am setting up a couple of antennas to connect 2 buildings about 300 feet
    > apart. I have discussed this with several people and a subject that came
    up
    > was antenna lead loss. One person said it was a big issue, and another
    says
    > it is nothing to worry about. Can anyone give me the straight scoop?
    BTW,
    > my antennas will be on roof tops, so I need enough lead length to get
    inside
    > to the access points.
    >
    > Thanks,
    >
    > Jerry
    >
    >
  2. Archived from groups: alt.internet.wireless (More info?)

    On Wed, 27 Oct 2004 16:40:02 -0700, "JerryK"
    <jerryk.nospam@nospam.com> wrote:

    >I am setting up a couple of antennas to connect 2 buildings about 300 feet
    >apart. I have discussed this with several people and a subject that came up
    >was antenna lead loss. One person said it was a big issue, and another says
    >it is nothing to worry about. Can anyone give me the straight scoop? BTW,
    >my antennas will be on roof tops, so I need enough lead length to get inside
    >to the access points.

    It's a BIG issue. At 300ft, you can probably afford quite a bit of
    loss. However, it's considered good form to calculate rather than
    guess. See:
    http://www.ydi.com/calculation/som.php
    use 300/5280 = 0.057 for the range in miles. Minimum fade margin is
    about 10dB. For an 802.11g link, running at 25Mbits/sec, you should
    aim for 30dB fade margin. Use 1.0dB for every connector pair.

    For cable loss, see:
    http://www.ocarc.ca/coax.htm
    You'll probably be using LMR-400 which eats 0.067dB/ft.

    If the numbers look bad, then I strongly suggest at least one end of
    the link uses a roof top radio, with no coax cable.

    If you want me to do the numbers for you, kindly disclose some
    hardware details (radios, coax type, coax length, antennas, antenna
    gain, range, 802.11a/b/g, etc).

    --
    # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
    # 831.336.2558 voice http://www.LearnByDestroying.com
    # jeffl@comix.santa-cruz.ca.us
    # 831.421.6491 digital_pager jeffl@cruzio.com AE6KS
  3. Archived from groups: alt.internet.wireless (More info?)

    And dont forget to add in the lightning arrestors!


    "JerryK" <jerryk.nospam@nospam.com> wrote in message
    news:41802fa5$1_1@127.0.0.1...
    > Hi,
    >
    > I am setting up a couple of antennas to connect 2 buildings about 300 feet
    > apart. I have discussed this with several people and a subject that came
    up
    > was antenna lead loss. One person said it was a big issue, and another
    says
    > it is nothing to worry about. Can anyone give me the straight scoop?
    BTW,
    > my antennas will be on roof tops, so I need enough lead length to get
    inside
    > to the access points.
    >
    > Thanks,
    >
    > Jerry
    >
    >
  4. Archived from groups: alt.internet.wireless (More info?)

    Jeff,

    What do you mean by a "Roof top radio with no coax"?

    On both sides, I am planning on hooking directly from the Access Point (ex.
    Dlink DWL-G700AP) to a directional panel antenna (claimed 16db gain). The
    cable length should be under 20 feet.

    jerry

    "Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
    news:lkh0o05rkgutrasordsv6rqgnn9lfihbcs@4ax.com...
    > On Wed, 27 Oct 2004 16:40:02 -0700, "JerryK"
    > <jerryk.nospam@nospam.com> wrote:
    >
    >>I am setting up a couple of antennas to connect 2 buildings about 300 feet
    >>apart. I have discussed this with several people and a subject that came
    >>up
    >>was antenna lead loss. One person said it was a big issue, and another
    >>says
    >>it is nothing to worry about. Can anyone give me the straight scoop?
    >>BTW,
    >>my antennas will be on roof tops, so I need enough lead length to get
    >>inside
    >>to the access points.
    >
    > It's a BIG issue. At 300ft, you can probably afford quite a bit of
    > loss. However, it's considered good form to calculate rather than
    > guess. See:
    > http://www.ydi.com/calculation/som.php
    > use 300/5280 = 0.057 for the range in miles. Minimum fade margin is
    > about 10dB. For an 802.11g link, running at 25Mbits/sec, you should
    > aim for 30dB fade margin. Use 1.0dB for every connector pair.
    >
    > For cable loss, see:
    > http://www.ocarc.ca/coax.htm
    > You'll probably be using LMR-400 which eats 0.067dB/ft.
    >
    > If the numbers look bad, then I strongly suggest at least one end of
    > the link uses a roof top radio, with no coax cable.
    >
    > If you want me to do the numbers for you, kindly disclose some
    > hardware details (radios, coax type, coax length, antennas, antenna
    > gain, range, 802.11a/b/g, etc).
    >
    > --
    > # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
    > # 831.336.2558 voice http://www.LearnByDestroying.com
    > # jeffl@comix.santa-cruz.ca.us
    > # 831.421.6491 digital_pager jeffl@cruzio.com AE6KS
  5. Archived from groups: alt.internet.wireless (More info?)

    On Thu, 28 Oct 2004 11:22:31 -0700, "JerryK"
    <jerryk.nospam@nospam.com> wrote:

    >What do you mean by a "Roof top radio with no coax"?

    That's where the access point is mounted in a waterproof box or is
    imbedded in the antenna. Power is supplied with either an independent
    cable run, or through the ethernet cable using PoE (power over
    ethernet). The big advantage is that it eliminates the coax cable
    loss problem and allows substantial flexibility in installation, that
    isn't possible with a big fat lossy coax cable run.

    It's fairly messy to repackage an indoor router/AP but possible.
    http://www.sveasoft.com/articles/armored/

    >On both sides, I am planning on hooking directly from the Access Point (ex.
    >Dlink DWL-G700AP) to a directional panel antenna (claimed 16db gain). The
    >cable length should be under 20 feet.

    I didn't realize that you already owned the hardware.
    http://www.dlink.com/products/?pid=326
    16dBi panel (patch) antennas are just fine. Probably too much gain,
    but with the added benifit of not hearing junk to the sides of the
    antenna pattern. You should have more than enough fade margin. If
    you're only using 20ft of unspecified coax cable, you should have
    enough fade margin for getting maximum speed from your bridge.

    I can work out the numbers, but you may have a bigger problem. I
    don't think the DWL-G700AP will act as a transparent bridge (also
    known as a "wireless bridge" or "bridge mode"). I'm looking through
    the data sheets and find nothing about bridging. This is strictly an
    access point used to connect from individual wireless clients and
    cannot be used to glue two networks together.

    Is there anything else you didn't mention? (type of coax, line of
    sight, fresnel zone clearance, interference potential, number of MAC
    addresses bridged (32 max for the cheapo bridges), traffic expected,
    etc.)

    --
    Jeff Liebermann jeffl@comix.santa-cruz.ca.us
    150 Felker St #D http://www.LearnByDestroying.com
    Santa Cruz CA 95060 AE6KS 831-336-2558
  6. Archived from groups: alt.internet.wireless (More info?)

    "JerryK" <jerryk.nospam@nospam.com> wrote:
    >What do you mean by a "Roof top radio with no coax"?

    An outdoor access point. Something like
    http://d-link.com/products/?sec=0&pid=303 where the feedline loss is
    approximately zero. You can use something like
    http://d-link.com/products/?model=DWL-1750 if you want an external
    antenna, and then you can keep your feedline short (though you've
    still got connector losses). N-Type connectors (and feedline and
    antennas) will keep your losses low...
  7. Archived from groups: alt.internet.wireless (More info?)

    JerryK wrote:
    > Hi,
    >
    > I am setting up a couple of antennas to connect 2 buildings about 300 feet
    > apart. I have discussed this with several people and a subject that came up
    > was antenna lead loss. One person said it was a big issue, and another says
    > it is nothing to worry about. Can anyone give me the straight scoop? BTW,
    > my antennas will be on roof tops, so I need enough lead length to get inside
    > to the access points.
    >
    > Thanks,
    >
    > Jerry
    >
    >
    Loss IS a big deal. You want to keep coax runs as short as possible. I'm
    sure someone on this group (Mr Leibermann?) can advise on figures. If
    you cannot get your AP close enough to the antenna, you should consider
    getting an AP that supports power over ethernet and put everything in a
    weatherproof box and mount it outside.
    Peter
  8. Archived from groups: alt.internet.wireless (More info?)

    Consider something like a Senao outdoor bridge CB-3 in an outdoor enclosure
    such as the rootenna which has an integral panel antenna.
    http://shop.defactowireless.com/s.nl/category.102/it.A/id.118/.f
    $170. {If you look real hard these can be had for about $150}. Some of the
    wireless mesh operators in NE Texas and Louisiana are using these for the
    final connection of community wireless to individual homes or business. The
    Senao device provides for power over Ethernet so all you need is an Ethernet
    cable to the box with power injected onto the Ethernet cable.

    The Senao card is a high powered 200 mW output with a +14 dBi panel antenna.
    802.11b only

    --
    Bob Alston

    bobalston9 AT aol DOT com
    "Sandy Baby" <bill@microsoft.com> wrote in message
    news:clrjd1$hfa$1@titan.btinternet.com...
    > JerryK wrote:
    >> Hi,
    >>
    >> I am setting up a couple of antennas to connect 2 buildings about 300
    >> feet apart. I have discussed this with several people and a subject that
    >> came up was antenna lead loss. One person said it was a big issue, and
    >> another says it is nothing to worry about. Can anyone give me the
    >> straight scoop? BTW, my antennas will be on roof tops, so I need enough
    >> lead length to get inside to the access points.
    >>
    >> Thanks,
    >>
    >> Jerry
    >>
    >>
    > Loss IS a big deal. You want to keep coax runs as short as possible. I'm
    > sure someone on this group (Mr Leibermann?) can advise on figures. If you
    > cannot get your AP close enough to the antenna, you should consider
    > getting an AP that supports power over ethernet and put everything in a
    > weatherproof box and mount it outside.
    > Peter
    >
    >


    ---
    Outgoing mail is certified Virus Free.
    Checked by AVG anti-virus system (http://www.grisoft.com).
    Version: 6.0.783 / Virus Database: 529 - Release Date: 10/25/2004
  9. Archived from groups: alt.internet.wireless (More info?)

    Hi Jeff,

    I own the antennas, but not access points. I am open to suggestions on
    brands and models. I like the idea of the roof top antenna with no coax,
    but the cost may be prohibited. I am not doing a "commercial" installation.
    A friend and I are just trying to share a connection between two hangars at
    an airport. My hangar has access to a wired DSL connection. His hangar is
    300 feet away and we want to hook him to my connection. We are mounting the
    antennas on the roofs and plan on placing the access points inside the
    hangars. We are trying to do this as cheaply as possible.

    Regarding your questions:
    "(type of coax, line of
    > sight, fresnel zone clearance, interference potential, number of MAC
    > addresses bridged (32 max for the cheapo bridges), traffic expected,
    > etc.)"

    Whatever coax I can get that will work is fine, but price is a
    consideration. I would love to be able to run 40 feet on each end, since
    that would mounting the access points much easier.

    There should be no interference. The roofs are approximately 25 feet and
    there are no interviening buildings.

    He will only have 2 or 3 system on his end, so we can go with the cheapo
    bridge.

    Traffic. On my end I will only use the connection once or twice a day. On
    his end maybe 5 or 6 times a day. The typical activity will be web browsing
    and email. No media players, streaming video, etc. So the load should be
    pretty light.

    Other factors. All systems will be PCs. I may also have a wireless router
    in hangar for my tablet.

    Thanks for your help,

    jerry

    "Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
    news:5fm2o0lvbsvg7elf1f8q77crdtfddiu2nm@4ax.com...
    > On Thu, 28 Oct 2004 11:22:31 -0700, "JerryK"
    > <jerryk.nospam@nospam.com> wrote:
    >
    >>What do you mean by a "Roof top radio with no coax"?
    >
    > That's where the access point is mounted in a waterproof box or is
    > imbedded in the antenna. Power is supplied with either an independent
    > cable run, or through the ethernet cable using PoE (power over
    > ethernet). The big advantage is that it eliminates the coax cable
    > loss problem and allows substantial flexibility in installation, that
    > isn't possible with a big fat lossy coax cable run.
    >
    > It's fairly messy to repackage an indoor router/AP but possible.
    > http://www.sveasoft.com/articles/armored/
    >
    >>On both sides, I am planning on hooking directly from the Access Point
    >>(ex.
    >>Dlink DWL-G700AP) to a directional panel antenna (claimed 16db gain). The
    >>cable length should be under 20 feet.
    >
    > I didn't realize that you already owned the hardware.
    > http://www.dlink.com/products/?pid=326
    > 16dBi panel (patch) antennas are just fine. Probably too much gain,
    > but with the added benifit of not hearing junk to the sides of the
    > antenna pattern. You should have more than enough fade margin. If
    > you're only using 20ft of unspecified coax cable, you should have
    > enough fade margin for getting maximum speed from your bridge.
    >
    > I can work out the numbers, but you may have a bigger problem. I
    > don't think the DWL-G700AP will act as a transparent bridge (also
    > known as a "wireless bridge" or "bridge mode"). I'm looking through
    > the data sheets and find nothing about bridging. This is strictly an
    > access point used to connect from individual wireless clients and
    > cannot be used to glue two networks together.
    >
    > Is there anything else you didn't mention? (type of coax, line of
    > sight, fresnel zone clearance, interference potential, number of MAC
    > addresses bridged (32 max for the cheapo bridges), traffic expected,
    > etc.)
    >
    > --
    > Jeff Liebermann jeffl@comix.santa-cruz.ca.us
    > 150 Felker St #D http://www.LearnByDestroying.com
    > Santa Cruz CA 95060 AE6KS 831-336-2558
  10. Archived from groups: alt.internet.wireless (More info?)

    On Fri, 29 Oct 2004 13:01:20 -0700, "JerryK"
    <jerryk.nospam@nospam.com> wrote:

    >I own the antennas, but not access points.

    Ok. We use the antennas. The existing Dlink DWL-G700AP radios will
    be used for local connections inside the hangars. You'll still need a
    pair of radios that can do bridging and a router.

    >I like the idea of the roof top antenna with no coax,
    >but the cost may be prohibited.

    Well, this is what you should have purchased:
    http://www.ydi.com/products/bridges/bridge-in-a-box.php
    $950 from MoonBlink for the pair. This is actually overkill as the
    specified range is 2 miles. There might be a cheaper incantation.

    >I am not doing a "commercial" installation.

    You're in an airport. The airport manager will launder your shorts in
    prop wash if you do anything less than a professional installation on
    his hangar. You can use inferior cheap junk for the radios and
    non-permanently attached boxes, but if you install a pair of coffee
    cans or similar abomination, you will be probably be asked to clean it
    up or replace it. I've been there in two different airports.

    >A friend and I are just trying to share a connection between two hangars at
    >an airport. My hangar has access to a wired DSL connection. His hangar is
    >300 feet away and we want to hook him to my connection.

    Before you continue with the wireless road to connectivity, please
    make an effort to check out any existing phone wiring or conduit
    between hangars. I setup a network between hangars at an airport long
    ago (using Arcnet and coax). Hangars tend to have quite a bit of
    conduit inside which eventually terminate at the telco MPOE (demarc).
    That's because telephone poles and dangling wires are not appreciated
    in the vicinity of things that fly through the air.

    If there's conduit, see if you can add some CAT5 or coax (RG-58a/u).
    You can go much farther than the official 100 meters if you observe
    some precautions and tolerate some limitations. I've posted comments
    on how it's done in alt.internet.wireless in the past. The longest
    I've done is slightly less than 1000ft using 10baseT.

    If you can't add cable, but there is existing twisted telco pair,
    determine who owns the wire and ask them if you can "borrow" two pairs
    between hangars. Although not officially supported, you can run
    10baseT over telco wire. You won't go as far as CAT5 or coax, but it
    will usually work.

    If wired is not an option, then I guess you gotta do wireless.
    However, before you embark on this adventure, do a site survey.
    Install Netstumbler on your Tablet PC. Drag it onto the roof and see
    if you can "hear" anything. Avoid using any channels that are already
    in use (1, 6, or 11). If there's a local comm shop, and they have a
    clue, ask them to fire up their spectrum analyzer on the 2400-2500Mhz
    band. There's quite a bit of junk around the typical airport that
    doesn't show up on Netstumbler. For example, Proxim/WMux backhauls
    used by Nextel and Cingular. Remote radar backhaul.

    >We are mounting the
    >antennas on the roofs and plan on placing the access points inside the
    >hangars. We are trying to do this as cheaply as possible.

    I usually ask my customers how much they want too spend on such
    things. Once established, I can better determine what can be done
    with their money, rather than throw together that absolute cheapest
    piece of junk, and spend my time fixing it later.

    >Regarding your questions:
    >"(type of coax, line of
    >> sight, fresnel zone clearance, interference potential, number of MAC
    >> addresses bridged (32 max for the cheapo bridges), traffic expected,
    >> etc.)"
    >
    >Whatever coax I can get that will work is fine, but price is a
    >consideration. I would love to be able to run 40 feet on each end, since
    >that would mounting the access points much easier.

    Well, you lose. My suggestions will involve minimizing the coax cable
    length, mostly because of the loss, but also because working with coax
    is a pain. See below.

    >There should be no interference.

    Assumption, the mother of all screwups. One of my friends just called
    asking what to do about interference. It seems he parked one end of
    his bridge in the path of a 10 watt TV station STL link. He's toast
    unless he can convince the radio station to move to a slightly
    different channel.

    >The roofs are approximately 25 feet and
    >there are no interviening buildings.

    Does that mean you have line of sight AND reasonable Fresnel Zone
    clearance? At 300ft, the midpoint Fresnel zone is only a few inches
    wide. Therefore, you need the width of the antenna, plus a few
    inches, clearance from the center line. If your shooting across any
    knife edges in the path, you will have a problem.

    >He will only have 2 or 3 system on his end, so we can go with the cheapo
    >bridge.

    OK. 32 MAC addresses will do fine. That what most of the cheap
    bridges will do.

    >Traffic. On my end I will only use the connection once or twice a day. On
    >his end maybe 5 or 6 times a day. The typical activity will be web browsing
    >and email. No media players, streaming video, etc. So the load should be
    >pretty light.

    Yeah, right. I made the mistake of showing everyone on my
    neighborhood WLAN how to get continuous background music from
    Shoutcast using Winamp. Now I've got a bunch of people pulling
    128Kbits/sec continuously. It only takes about 10 of those streams
    and my bandwidth is gone.

    >Other factors. All systems will be PCs. I may also have a wireless router
    >in hangar for my tablet.

    Ok. We'll use your existing wireles access point for inside your
    hangar. Instead of multiple suggestions, I'll just supply the one I
    think will work. You can add or subtract as necessary. I just don't
    have the time to present all the options, configurations, and
    mutations.

    First you'll need a pair of radios that will do transparent bridging.
    I suggest Linksys WAP54G running in bridge mode. About $70/ea.
    Here's the part you won't like. The radio goes inside the hangar, but
    up near the ceiling. Punch a hole in the SIDE of the hangar and
    install a proper PVC rams head entry. The coax comes down from the
    roof, through the entry pipe, and directly to the radio. I'm guessing
    about 6ft of coax. At that length, you can use just about any type of
    coax. However, I still suggest using LMR-400. Instead of the usual
    pigtail or adapter plus N coax extension, we use a piece of LMR-400
    with an N-connector on one end and a R-TNC on the other. See:
    http://www.fab-corp.com/A1.htm
    About $30 for 10ft.

    Some notes on the RF parts. Do NOT use any right angle N connectors.
    I'll spare you the reasons why. Also, no sharp bends in the coax.
    Make sure you have a drip loop for water at the rams head. Wrap the
    connectors first in 1" wide teflon tape, and then embalm that in
    decent electrical tape. The TFE keeps the tape from making a sticky
    mess and will prevent capillary action. If you're really cheap,
    cellophane wrap will work.

    So, now you ask how does one get power up there? The WAP54G has a
    really nifty switching power supply inside. The unit will run on 5VDC
    (actually 3.7VDC) so wiring loss is not much of a concern. Build an
    extension cable for the power connector on the WAP54G to the 12VDC
    wall wart supplied with the unit. Don't butcher the wall wart cable
    by chopping off the connector. Go to Radio Shock, buy the parts, and
    make an extension. Zip cord (AC power cord) will work. Watch the
    polarity so you don't blow it up.

    How you mount the WAP54G near the ceiling is your problem. Just make
    sure you support the cables so their weight doesn't extract them from
    the WAP54G.

    You'll also need a piece of CAT5 cable between the ethernet port on
    the WAP54G and the rest of your LAN (i.e. your router). You can crimp
    your own or pay for pre-made cables. Up to this point, both ends of
    the puzzle are essentially identical. Effectively, you've build an
    ethernet extension cord.

    Wiring is like this:


    [Linksys]==< >==[Linksys]
    [ WAP54G] [WAP54G ]
    | |
    | |
    | |
    phone | |
    line | |
    | | |
    [ADSL] |====/ \==[5 port ] |==[PC1]
    [modem]==[router]=|==[PC1] [ethernet]=|==[PC2]
    |==[PC2] [ switch ] |==[PC3]
    |==[PC3] |
    [ Dlink ]=====| |==[Dlink ]
    [DWL-G700AP] [DWL-G700AP]


    The added router can be just about any type of router. I tend to use
    Dlink DI-604 because they're cheap and the later units (Rev E1) seem
    to work well for me. The back of the DI-604 includes a 4 port
    ethernet switch which is where your PC's will plug in. Therefore, it
    should be located near the PC's.

    The WAP54G does not have a built in switch so you'll need to add one
    at the remote end. It's better this way or you would have ended up
    running wires up to the ceiling.

    Selection of channels and SSID is fairly simple. The Dlink radios
    should NOT be on the same channel as the wireless bridge or you'll end
    up interfereing with yourself. The SSID and WEP/WPA encryption keys
    on the two Dlink access points can be the same to make roaming easier.


    --
    Jeff Liebermann jeffl@comix.santa-cruz.ca.us
    150 Felker St #D http://www.LearnByDestroying.com
    Santa Cruz CA 95060 AE6KS 831-336-2558
  11. Archived from groups: alt.internet.wireless (More info?)

    Don't listen to all this bullsh*t, I have a setup with Dlink 800
    access point and Dlink 810 bridge, both cost about 75.00 us each, they
    are connected to external antenna with 13dbi. Access point is mounted
    in a box outdoors with cat 5 cable back to the router and 5' of lmr
    195 coax to the antenna, the other end has 20" of lmr400 coax between
    the bridge and the antenna with about 50' of cat 5 cable to my pc. The
    distance I am bridging is well over a mile. My internet speeds are
    stable and downloading at about 1 megabit. I also have a group of
    trees between my antenna and the other antenna, doesn't seem to pose
    too much of a problem. At 300 ft. you may be able to mount your
    antenna's internaly, especialy if you have a window that faces the
    other hanger. Glass doesn't block the signal to any great degree. If
    you would like any other info for this setup, email me at
    pdj@NOSPAMuniserve.com
  12. Archived from groups: alt.internet.wireless (More info?)

    On Fri, 29 Oct 2004 16:07:28 -0700, Jeff Liebermann wrote:
    ......
    > First you'll need a pair of radios that will do transparent bridging.
    > I suggest Linksys WAP54G running in bridge mode. About $70/ea.
    > Here's the part you won't like. The radio goes inside the hangar, but
    > up near the ceiling. Punch a hole in the SIDE of the hangar and
    > install a proper PVC rams head entry. The coax comes down from the
    > roof, through the entry pipe, and directly to the radio. I'm guessing
    > about 6ft of coax. At that length, you can use just about any type of
    > coax. However, I still suggest using LMR-400. Instead of the usual
    > pigtail or adapter plus N coax extension, we use a piece of LMR-400
    > with an N-connector on one end and a R-TNC on the other. See:
    > http://www.fab-corp.com/A1.htm
    > About $30 for 10ft.
    >
    > Some notes on the RF parts. Do NOT use any right angle N connectors.
    > I'll spare you the reasons why. Also, no sharp bends in the coax.
    > Make sure you have a drip loop for water at the rams head. Wrap the
    > connectors first in 1" wide teflon tape, and then embalm that in
    > decent electrical tape. The TFE keeps the tape from making a sticky
    > mess and will prevent capillary action. If you're really cheap,
    > cellophane wrap will work.
    >
    > So, now you ask how does one get power up there? The WAP54G has a
    > really nifty switching power supply inside. The unit will run on 5VDC
    > (actually 3.7VDC) so wiring loss is not much of a concern. Build an
    > extension cable for the power connector on the WAP54G to the 12VDC
    > wall wart supplied with the unit. Don't butcher the wall wart cable
    > by chopping off the connector. Go to Radio Shock, buy the parts, and
    > make an extension. Zip cord (AC power cord) will work. Watch the
    > polarity so you don't blow it up.
    >
    > How you mount the WAP54G near the ceiling is your problem. Just make
    > sure you support the cables so their weight doesn't extract them from
    > the WAP54G.
    >
    > You'll also need a piece of CAT5 cable between the ethernet port on
    > the WAP54G and the rest of your LAN (i.e. your router). You can crimp
    > your own or pay for pre-made cables. Up to this point, both ends of
    > the puzzle are essentially identical. Effectively, you've build an
    > ethernet extension cord.
    >
    > Wiring is like this:
    >
    >
    > [Linksys]==< >==[Linksys]
    > [ WAP54G] [WAP54G ]
    > | |
    > | |
    > | |
    > phone | |
    > line | |
    > | | |
    > [ADSL] |====/ \==[5 port ] |==[PC1]
    > [modem]==[router]=|==[PC1] [ethernet]=|==[PC2]
    > |==[PC2] [ switch ] |==[PC3]
    > |==[PC3] |
    > [ Dlink ]=====| |==[Dlink ]
    > [DWL-G700AP] [DWL-G700AP]
    >
    >
    > The added router can be just about any type of router. I tend to use
    > Dlink DI-604 because they're cheap and the later units (Rev E1) seem
    > to work well for me. The back of the DI-604 includes a 4 port
    > ethernet switch which is where your PC's will plug in. Therefore, it
    > should be located near the PC's.
    >
    > The WAP54G does not have a built in switch so you'll need to add one
    > at the remote end. It's better this way or you would have ended up
    > running wires up to the ceiling.
    >
    > Selection of channels and SSID is fairly simple. The Dlink radios
    > should NOT be on the same channel as the wireless bridge or you'll end
    > up interfereing with yourself. The SSID and WEP/WPA encryption keys
    > on the two Dlink access points can be the same to make roaming easier.


    Thank you very much!!!

    I will really appreciate all of the recommendations and advice on
    installation and parts. I will post a report when we get it up and running.

    Jerry
  13. Archived from groups: alt.internet.wireless (More info?)

    I've had good luck with the D-Link 800/810 set as well, but I'm sure the
    Linksys would work well, too. One nice thing about the D-Link 800 is that
    it can be found cheap (around $25) on the surplus/refurb market, and you
    can download the 810 firmware into the 800 and make it into an 810. And,
    the 800/810 pair will talk at 22 Mbs instead of 11 Mbs if the signal is
    strong enough.

    I also agree with keeping the antenna length as short as practical. Even
    the LMR400 cable loses a significant fraction of the signal if you go very
    far at all. I mount the AP or bridge near an outside wall, then run a
    short coax out to the antenna on the outside of the building. I've used 10
    - 25 feet of LMR400 and had good results. But, of course, every situation
    is unique, and a couple/few db loss on a coax run could make a big
    difference in your ultimate throughput in any given situation.

    Look at www.fab-corp.com under the heading "LMR Coaxial Cable". They list
    the db loss of various types per 100 feet. If you really have to have a
    long run of coax and can't accept much loss, they probably have a solution
    for you if you want to spend enough and if you deal with thick, stiff coax.
    They do have one type (LMR-900) that has less than 3 db loss per hundred
    feet, and it's about $3 per foot. And they carry two other coax that are
    more expensive than that one, but they don't list the loss on their
    website.

    LMR-400 loses over 6db per hundred feet, so even a 50 foot length of it
    will lose over half the signal. You have to look at your total gain &
    loss. You can offset coax loss with a higher gain antenna to some extent.


    pdj@uniserve.com (Paul James) wrote in news:94cef63c.0410302350.15701ec7
    @posting.google.com:

    > Don't listen to all this bullsh*t, I have a setup with Dlink 800
    > access point and Dlink 810 bridge, both cost about 75.00 us each, they
    > are connected to external antenna with 13dbi. Access point is mounted
    > in a box outdoors with cat 5 cable back to the router and 5' of lmr
    > 195 coax to the antenna, the other end has 20" of lmr400 coax between
    > the bridge and the antenna with about 50' of cat 5 cable to my pc. The
    > distance I am bridging is well over a mile. My internet speeds are
    > stable and downloading at about 1 megabit. I also have a group of
    > trees between my antenna and the other antenna, doesn't seem to pose
    > too much of a problem. At 300 ft. you may be able to mount your
    > antenna's internaly, especialy if you have a window that faces the
    > other hanger. Glass doesn't block the signal to any great degree. If
    > you would like any other info for this setup, email me at
    > pdj@NOSPAMuniserve.com
    >
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