These are photographs that were taken while I was installing a self-made mast for an 802.11b antenna. If you have a concrete or brick chimney, then you could probably do something similar.
If you already have the tools, then you will need to spend about $20 to buy the pipe and fastening hardware. I bought everything at the Home Depot on King Street North in Waterloo.
The LMR-600 cable was purchased from Mark Dotzert. This is 60 feet, which cost a few hundred dollars. The antenna is a SPDG160 that was locally manufactured by SuperPass. The antenna purchase was cash-and-carry.
Note that this type and amount of cable was excessive for the job, but I used it because I had it handy. 20ft of LMR-400 would have been more appropriate.
The cable is N-male and the antenna is N-female. The cable has a diameter of slightly less than 0.75 inches, which means that its gauge is "RG-8". "TNC" connectors are usually used to crimp RG-8 antenna cable.
Sealing the joint against moisture.
The LMR-600 cable is stiff and difficult to work with. The antenna has been attached to the steel pipe with hose clamps. If you do not shim the clamp, then turn the screw up until the point that it suddenly bites. One clamp is enough, but I used two for stability.
A close-up photograph of a hose clamp, concrete screw, conduit clamp, and masonry drill bit.
This is the chimney before any work has started.
Drilling holes and hammering the lag shields and anchors.
Levelling and mounting the mast. I had to chisel the concrete to get the mast perfectly vertical. The mast is lighter than it looks and concrete will usually fail before metal fasteners fail. Both joints can hold my weight (225lbs).
The screws should be caulked to prevent freezing damage in the winter, and it may have been better to use one u-clamp instead of the conduit clamps. If the concrete around the screws cracks, then all three on a side are likely to pull out.
I was able to cut a notch into a vent grille and pull the cable into the attic. Don't roll the cable before you ground it, or it will act like a solenoid coil if the antenna is struck by lightning.
I pulled ethernet cable from the attic to my primary gateway machine inside the house. A Lucent RG-1000 access point is connected to the antenna cable with a "pigtail" adapter.
The final installation as seen from the street and from the roof.
PS: The mast survived a storm that pulled shingles off the roof, so it seems that the basic idea is sound.
Darik Horn <dajhorn at waterloowireless dot org>, 2002-05-16