Light Pole Antenna Jig & Mast Kit - Designed By Earl Pack

Use the following instructions to construct a jig and mast kit to quickly and easily utilize a standard 4” square light pole to put up an antenna with a base elevation of 20-30’.  The heights of the square light poles I have worked with vary from 15-25’, so the maximum height of your antenna is limited by the light pole.  However, this kit will work on any height light pole.  This kit is simple and inexpensive (~$65) to build (about 3 hours) and will fit in the trunk of any car.  The kit does not include the antenna nor the coax feed line.


PURCHASE PARTS
Item     Qty     Description
1a           3       Chain Link Fence Rail Top Pipe 10’ long or
1b           8       War surplus 2" x 4' aluminum or fiberglass pipe
2             3       Fence Rail Top Pipe Couplings (Not req. if use 1b)
3             8       1/2” PVC 90 Fitting
4             6       1/2" PVC T Fitting
5             1       1/2" PVC Schedule 40 Pipe 10’ long
6             1       PVC Cleaner / Glue set
7             1       75’ of 1/16” nylon cord on wind up loop
8             1       3/4” Pulley
9             2       1/4'” Spring Link
10           2       Bungee 2’ cords
11         20”     Fencing wire
12           1       3/4” Outside diameter Fender or Dock Washer
13           1       1/4” x 3” carriage bolt
14           2       1/4" Nut

15           1       3/8” Nut

TOOLS
- PVC Pipe Cutter
- Hack saw
- 3/32” drill bit
- Drill
- Small Steel File
- If possible:
-   Drill Press
-   Steel Pipe cutter
-   Bench grinder

PRECUT PVC PARTS
8 pieces of 1/2” PVC pipe 1-5/8” long

6 pieces of 1/2” PVC pipe 4-1/4” long

1 pieces of 1/2” PVC pipe 4-1/2” long

2 pieces of 1/2” PVC pipe 2” long

LIGHT POLE CAGE AND CAP
Refer to the figure and use a PVC Pipe cutter tool to cut the parts listed from the 1/2 inch PVC Schedule 40 pipe. The same length or type parts in the figure are the same color. Be sure not cut the pieces shorter than specified.  With the PVC Pipe cutter this will take about 30 minutes. You can use a hacksaw to cut these pieces, but it will take a little longer.

Gluing the parts is a little tricky because the finished Cage must be square in order to fit together properly. Assembling the parts in the order presented should help you get it right the first time. This also gives you a little practice gluing PVC before you have to glue the critical connections. For all connections apply the cleaner on the surfaces to be joined then apply the cement to those same surfaces. Hold the pieces together until the glue sets (about 30 sec) because the fittings have a tendency to slide back off the nipples.

The next figure details the sub-assemblies. Start joining the pieces by gluing one of the 4-1/4” nipples into the bottom connection of a T fitting. Glue the other end of this nipple into the bottom connection of another T fitting. Make sure the T fittings are square with each other by pressing the assembly onto a flat surface immediately after gluing. This is the Jig Upright assembly. You only have a few seconds to get this right. Assemble the second Jig Upright for a total of (2) assemblies.

Continue by gluing one of the 90 fittings to one of the 1-5/8” nipples. This is the 90 plus nipple assembly. Repeat for a total of (6) assemblies. Next glue one of the 1-5/8” nipples into the bottom connection of a T fitting. This is the T plus nipple assembly. Repeat for a total of (2) assemblies.

Dry fit the following parts together by lightly pushing four of the 90 plus nipple assemblies into one of the Jig Upright assemblies. Do not push them together too hard or you will have a hard time getting them apart. Make sure these 90’s are square by pressing this assembly onto a flat surface with the open end of the 90’s facing the flat surface. Adjust the 90 plus nipple assemblies as needed. This will be your only practice to get the parts square.

Remove one of the 90 plus nipple assemblies from the Jig Upright assemble, glue and reinsert it into the new assembly. Make this 90 plus nipple square by immediately pressing the whole assembly onto a flat surface and adjusting as needed. You only have a few seconds to get this right. Repeat this process for the other three 90 plus nipple assemblies. This is now the Cage Cap assembly.

Lightly push the two remaining 90 plus nipple assemblies into the remaining Jig Upright assemblies. Lightly push two of the T plus nipple assemblies into this same assembly. Make sure these 90 and T fittings are square by pressing this assembly onto a flat surface with the open end of the 90’s and the T fitting facing the flat surface. Repeat the process discussed previously to glue these parts together squarely. Glue four of the 4-1/4” nipples into this last assembly. All of the nipples should be pointing the same way.

Finish the loop on the Cage assembly by gluing two of the 2” nipples into the T fittings of the Cage assembly. Glue one of the 90 fittings to the 4-1/2” nipple. Glue the remaining 90 to the other end of the 4-1/2” nipple. Quickly check and adjust this to fit with the nipples that you glued into the T’s of the Cage for form the loop. Also quickly make sure this part is square by pushing it onto a flat surface. You have to be quick on this assembly. Glue this last assembly to the nipples that you glued into the T’s of the Cage.

Lightly test fit the Cage and Cage Cap together to making sure all parts are square. If the assemblies are not square, you will have to start over with new pieces. DO NOT push the Cage and Cage Cap together otherwise you will soon hear yourself saying, “I sure wish I had not done that”. Before connecting the Cage Cap to the Cage, you will first need to remove the pipe fitting taper from the 90 fitting of the Cage Cap.

To accomplish this task you will need to make the Taper Cutting tool discussed below. Unfortunately I could not purchase anything with the right diameter. Besides we like to tinker with things so way not make our own tools while we are at it. The inside diameter of the fittings must be at least 0.85 inch. This is just slightly larger than the outside diameter of the pipe. The pipe must slip easily all the way into the base of the 90 fittings. This is a critical step to make sure the Cage Cap fits easily onto and off from the Cage. Check each fitting individually with a piece of 1/2” PVC pipe to make sure it is loose enough but not too loose.

With the taper removed, fit the Cage Cap tightly onto the Cage. The top of the Cage has the loop on the back. Mark the Cage Cap with an up arrow so that it will always be reassembled onto the Cage the same way. Drill a 3/32” hole through the 90 fittings and the 4-1/4” nipple. The hole should be 1/2 way between the end of the 90 fitting and the elbow of the 90 fitting. Drill all 4 - 90’s of the Cage Cap. A drill press will make it a lot easier to get the holes straight. Remove the Cage Cap and make sure the holes in the pipe are about 1/2" from the end of the nipples. Use some fencing wire to make removable pins for these holes.

TAPER CUTTING TOOL
Use a hack saw, bench grinder, and steel file to cut and shape a 3/4 inch steel washer like shown in the figure. Use the steel file to sharpen the front cutting edge of the tool. Once the rough shape is cut out and the burrs have been removed, bolt the washer onto the carriage bolt like shown in next figure. While rotating the cutter in a drill press, use a file to adjust the diameter of the cutter so that it removes just enough of the pipe fitting taper. Test it on a spare 90 fitting.

LIGHT POLE MAST
Use a hacksaw or steel pipe cutters to cut the 3 Fence Rail Top Pipes in half (63” lengths). This will give you 30 foot of mast. After cutting, you may need to ream or file out the cut ends of the pipe so that the taper ends will slide inside. Place one Fence Rail Top Pipe Coupling onto the end of the piece of pipe without the factory taper. Drill a hole through the coupling and the pipe and screw in a sheet metal screw to hold them together. Repeat for 3 sections of pipe. Use whatever size screw you have available. Use tape to wrap around the coupling or slip bicycle tire inner tube over the coupling to prevent scratching of the light pole. Secure the pipes together in a bundle with the two bungee cords for easy transportation.

PUTTING UP THE ANTENNA

Assembling and putting an antenna up a light pole with this jig take about 15 minutes. Begin by fitting the Light Pole Cage around the light pole with the loop at the top. Use the wire pins to secure the Cage Cap to the Cage. The cage should be oriented on the light pole so that the antenna will not go through the light (180 deg from the light if possible). If you are by yourself, you need to lay everything out at the base of the light pole so that you can easily access it without moving.

Attach the antenna to one of the factory tapered Fence Rail Top Pipe sections. Then attach the coax to the antenna and tie the coax to the pipe with a tie wrap. Slip the pole on which the antenna is connected into the Light Pole Cage loop. Attach the pulley to the antenna mounting bracket and to the Light Pole Cage loop with the Spring Link as shown in figure. Use the cord to pull the Light Pole Cage up to the top of the pipe section. Push the pipe section up and insert another section in the bottom end. Use all of the factory tapered sections first. The pipes with couplings should be at the bottom of the mast assembly to improve stability. As a new section of pipe is added, continue to use the cord to pull the Light Pole Cage up until it stops at the top of the light pole. Continue to add pipe sections until there is 10-15’ extension beyond the top of the light pole. Use good judgment for stability. The extension may need to be shorter if there are high speed winds.

After the last section of pipe is inserted, place the base of the pipe on the base of the light pole next to the pole itself. “Maypole” or wrap the cord around the mast, coax, and light pole. Pull the cord tight as you go and the stretch of the nylon will lash everything tightly together and make it quite stable. Once the cord is wrapped all the way around and nearly down to the base of the light pole, put a “larks head knot” in the cord and slip it over one end of the bungee cord and secure the other end of the bungee cord to the bottom of the light pole to keep the cord tight. Your antenna is now ready for use.

TAKING DOWN THE ANTENNA
Taking down the antenna is mostly the reverse of putting it up. However, keep the Light Pole Cage pulled up as high as possible as the pipe sections are removed. If you don’t keep the cage at the top of the mast while the mast sections are removed, the mast pipe will bind and possibly bend and become very difficult to take down, NOT FUN. When taking down the antenna use two people with one person manning the cord. After you have done it a few times, you can do it by yourself.