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Move Your Access Point Outdoors?  Here's How.

Image of Outdoor AP Image of Outdoor AP v.2

General Facts:

Our Goal:

Our goal is to use an exiting access point and without modifying the system build a wireless bridge that can make a one mile point to point link.  We want to remain strictly legal and extend our range.

In order to accomplish this goal we will need to hit the following milestones:

  1. Build  an antenna enhancement which will not violate the integrity of our existing system.
  2. Build a weather proof container for our AP.
  3. Carry power to the AP without running AC to our roof top (a decidedly bad idea).
  4. Move our AP out of the house and up onto the roof or side of the building where it has clear line of site to the other end of our link.


Milestone One:

I have modeled two common access points.  The WAP-11 and the DWL-1000AP.  You will discover other models for those AP's here.  That problem is solved.  There are any number of ways a simple reflector can be added to the mounting box for you AP which will yield a good reflector.

Milestone Two:

Weather proof containers can be purchased at the hardware store and if you intend to deploy a link in a commercial or professional setting I'd recommend you go that route.  These things are UV proof and provide many other nice features.  If you are interested in saving money, here is an easy way to do that.  No doubt in your area there is a Restaurantthat serves really fine food =).  As it happens these folks have to order large quantities of seafood and other products and quite often those products are shipped in plastic containers *very* similar to tupperware.  It is likely you will be able to obtain several for the asking, if you are gracious enough to have a meal and complement the cook.  The ones I use are about 16 inches by 11 inches by 4 inches and are used to ship seafood.  They have a snap on cover and very much resemble tupperware.

  1. Your plastic box can't be sealed to be air tight.  If it is you will have condensation and heat problems.  You will need to ensure there is a 1/8" drain hole in the very bottom of the box to allow any condensation to drip out of the box.
  2. You will need to create vents in the side of the box which will allow for the escape of heat but which will prevent wind blown water from entering the container. A good way to do this is to use a small diameter plastic pipe pushed through a hole in the side of the box and tilted downwards.  The pipe should be a minimum of 1/4" in outside diameter. Put one on either side of the box near the top.
  3. You will also need a port on the bottom of the box through which your wires exit the box. You can use a bit of plastic pipe for this as well.  These wires will be one Cat-5 (the network wire) and two ten or twelve gauge wires you use to extend the power adapter which came with the unit.
  4. You need to make a provision for attaching the box to something on your roof.  A wall mount (high up on the side of  the house is easy, you just screw four one inch sheet rock screws through the back of the box into the side of the house, or an eve or soffett.  Mounting upon a pole is more complex but you can purchase UV proof plastic wire ties in sixteen to eighteen inch lengths and feed these through small slits made in the back of the box.  Be sure to seal them after mounting with silicon caulk.
  5. You will also need to run a ground wire from the reflector screen you will install in the box to a ground stake outside your home.  Use 10 or 12 gauge stranded copper wire to connect from the screen reflector to the ground stake.  Run this wire in as straight a path to ground as you are able.  Use a section of 8 or 10 foot copper clad grounding rod from the hardware store for this purpose.  Cut it in half and drive it nearly all the way into the ground.  Watch for underground wires and pipes near the house.  Use the other half on your friends installation at his house.  NOTE:  If you want a really good ground (and really good grounds help things a bunch) or if you have dry sandy soil,  get a section of copper plumbers pipe 5/8 inches in diameter, cut it in half and drive it down into the ground to use as your stake.  When it is installed, mix up a cup of brine by heating four to six tablespoons of table salt in a cup of water and pour that slowly into the pipe, all the while letting is soak into the ground inside the pipe.
  6. After you have made your vents and prepared the outside of your box, you need to install the reflector(s) in the box.  The links for the different types I have tried are above.  Eventually I'll have drawings of those designs on line, but for now just cut yourself a sheet of tin foil, on quarter inch wire mesh, or copper plumber's flashing which is 5 inches tall and ten inches wide.  Affix this to the back of the box so that you can mount the access point above it and attach your ground wire.  Make a good mechanical attachment between the ground wire and the reflector.  If possible solder the joint.  Seal the joint with silicon caulking so that no condensation or moisture from the air can get to it.
  7. Now you need to install a spacer block in the box.  This may well be attached through the reflector screen.  No problem.  This spacer block should allow you to mount the access point so that it's antenna(s) are centered above the reflector and between 3/4 inch and 1 and 1/4 inches above it.  Gain goes up as you near 3/4 inch but so does reflected power, gain goes down as you approach 1 and 1/4 inches but so does reflected power.  In general one inch is just about ideal.  This remains true for any AP having dipole antennas.  Both the WAP-11 and the DWL-1000AP have dipole antennas.
  8. Install your ether net cable.
Milestone Three:
  1. Mount your access point to the spacer block and connect the power cable but do not plug the power cable into the wall.
  2. Measure off enough length on the power cable to give yourself a bit of slack, one foot is plenty, and split the power cable down the middle.  DO NOT CUT IT YET.  What you are doing is separating the two wires from each other.
  3.  Now MARK only one of the wires with a piece of tape by wrapping the tape completely around the wire.  This is important! Getting your wires crossed here will destroy your access point.  This bit of tape prevents you from confusing the wires.  Cut through the tape marker and the wire it wraps around so that a bit of tape remains on each end of the cut wire.  Now cut the other wire.  You now have prepared the power cable for the insertion of the extension wire(s).
  4. Strip back the wire which is not marked with tape.  Prepare a 25 foot (but what if I need more) piece of 10 or 12 gauge stranded copper wire (radio shack has it) by stripping both ends.  At this point make sure your wire is running through the hole you prepared in the box for your power cable. Connect the wire into the cable run and solder and seal with silicon caulk.  Repeat the process for the other side of the cable run, the one which you marked with tape.  You have now extended your power cable by 25 feet.
Milestone Four:

It is now time to install this puppy on the rooftop or side of your house.  This process will vary but here are some things you should think about.

  1. Be careful on the roof.  It takes a lot more energy to climb up it that it does to fall down it.  It takes even more energy to climb up it after you have fallen down it the first time.
  2. Don't attach the unit to a heat or electric source.
  3. Don't install the unit near another antenna.  Keep it away from your TV, CB, or Ham radio antenna.  The other end of the building looks better.
  4. Minimize obstructions between you and your preferred direction.  Maximize obstructions in directions you do not wish to cover.  For example I would not place an antenna on the south side of a roof if I were trying to point at a station on the north side of the building unless I had no other choice.  Ideally I am going to place an antenna so that it is on the nearest point of the building towards the remote station.  This allows me to place it a bit lower (usually) and actually uses the building as an obstruction to protect me from interference from other directions.
  5. Don't forget to seal things nice and tight when you have everything installed.  Go around the outside of the lid of the box with the silicon caulk and seal the lid down onto the box.
  6. Don't forget your ground wire.
  7. Don't forget your ground wire.
  8. Did I say, "Don't forget your ground wire?"
  9. Do try to obtain clear line of sight to your intended coverage area.  The frequencies we are working with here are really severely absorbed by trees and vegetation.  They are blocked by buildings and other structures.  They are bent by roof edges and other structures.  Ideally you are going to be able to clearly see your area of coverage and you are not going to be looking through a hole in the trees.  Between buildings is much better than between trees, given the same clearance.
  10. Sometimes on really short links (less than 1/4 mile) it is possible to bounce your link off of a water tower, metal building, or other similar large metallic structure.  This does not always work and you absolutely must have clear line of sight from both ends of the link to the object you are going to try to use as a reflector.


Conclusion:

I built one such system and placed it upon my roof for an afternoon of testing.  The pictures are below.  I was able to very easily make a one mile link to a laptop on the other end which had attached to it the dish template linked elsewhere on this page.  I used a DWL-1000AP as the base unit.  This unit produces about 35 mw of output power. One mile on 35 mw is nothing to sneeze at.  I believe my range estimate for this system is conservative.  I believe I will find that I am able to complete two mile links using this system without too much trouble, so long as I am careful in following the reflector designs linked above.  When I have time to build one of these things while a camera is handy, I will post pictures linked to the steps above.  Hopefully that won't be too long.  If anyone beats me to that, by all means send me the pics and I'll link them in to these instructions.  If you find anything in these instructions which needs amending please let me know.




Lets have a look at the pictures.

 
 

Picture of Parts and Tools
Gather your parts up.  Here is a picture of the parts I used. The first thing we will do is build a nice little wall mount for a DWL-1000AP.  In my case I am not too worried about the appearance of this construct.  I am building the unit as "proof of concept" for another project.  I am in a hurry and just want to give you the basics. 
 
  • Observe the "First Rule"; "First make it work, then make it work (fill in blank here)."
Attach the small wooden block to the back of the DWL-1000AP. I used the screws which shipped with the AP.
Attach that assembly to a 9 inch pie tin.  I used the staple gun you see in the parts picture.
Hook up the cables and open a slot in the bottom of the pan for the cables to run thru.  This is all you need to do if you are going to mount this AP on a wall or in a closet indoors.  The radiation pattern for this AP has been modeled. To see it click on the picture to the right.
If you intend to mount the access point out of doors, say on your roof, you will need to build an enclosure around it.  In this case I used a plastic box used to ship seafood to restaurants.  Mounting your AP out of doors is appropriate when you want to make a long link and need to clear line of sight between a similar unit mounted remotely.  This particular AP has been tested to 2.2 miles. Testing was done using this parabolic dish at the  remote end of the link, not fresnel clean @1MBits, and 0.9 miles with a parabolic dish at the remote end of the link, fresnel clean @11MBits. An easier parabolic design is here.
 
 
Above is the back side view of the "fish box" as I am preparing it for the plastic wire ties I use to mount it upon a pipe on the roof.  To the right is a front view of the box with the cover off.  NOTE THE GROUND WIRE IS ATTACHED DIRECTLY TO THE PIE TIN. NOTE YOU SHOULD HAVE ONE ON YOURS AS WELL!
Finished with the packaging.  Spray paint it a nice white or off white to help to keep the hardware cooler.
There remains the matter of the splicing of the DC power leads to make them longer. 
The pictures below show how to do that properly so that you avoid toasting your AP.
  1. Prepare a piece of Cat-5 wire, 25' long. 
  2. Join all the solid colored wires at each end of the cable into one wire by twisting and soldering their ends. 
  3. Now join all the striped wires at each end of the cable by twisting and soldering their ends.
  4. You now have a cable in your hands we can say consists of two wire bundles, one "stripes" (striped colors) and the other "solids" (solid colors).
  5. Double check your work.  If you get the above wrong, you will be buying a new access point.
  6. Now separate but DO NOT CUT the power cable as shown.
  1.  Cut ONLY ONE SIDE OF THE POWER CABLE and splice in your Cat-5 "solids" wire.  Make sure you use the bundle of solid colored wires on each end of the Cat-5 cable.
  2. If you get this step wrong you will be buying a new access point.
  1. Cut the other power lead and connect in the other half of the cat-5 .  That would be the "stripes" bundle on the Cat-5 cable.
  2. Double check the connections to be certain that you have made no mistakes. 
  1. Solder and tape the connections.
  2. Waterproof the connections.
 

-m-