Tripod to convert ground spike ham vertical antenna to POTA Performer

The build consists of a spike mount telescopic 5.7M antenna and feed point and the  tripod made from 3d printed parts and one inch or 32mm PVC pipe. The telescopic antenna, feed point and spike are available from many suppliers on Amazon, AliExpress and EBay.  Search for "5.7M/16.4 ft HF vertical antenna".  The cost is less than $50.

The tripod is easily assembled, light weight and very inexpensive. Pipe is cut to size and screw plugs and feet are glued into the ends of the pipe. The screw plugs on the legs and mast simply screw into sockets with matching threads in the center hub. Legs and mast can be unscrewed for more compact storage. The ground spike fits in a hole in the top of the mast.

PVC Pipe

There are model files for 1” Schedule 40 and SDR21 pipe as well as 32mm metric pipe for the rest of the world.  You will need a ten-foot (3meter) length of one inch PVC pipe, Schedule 40, the thinner walled SDR21 pipe or 32mm  PN10 pipe.  One-inch pipes are both readily available at big box DIY stores such as Lowe’s or Home Depot.  The one-inch pipe is tested but metric parts have not been tested.

Printing

Use PETG. PLA is brittle and breaks more easily. PETG is less likely to deform if left in a car on a hot, sunny day. 1 printed using Orca Slicer’s “.020 Strength” setting. This resulted in six wall loops and 25% infill. No supports were needed. There are models for three types of PVC pipe: 1 inch Schedule 40, 1 inch SDR21 and metric PN10 32mm O.D., 27.2 I.D.

For 1 inch Schedule 40 PVC print: 3x stakefoot1inSch40.stl, 4x scruplugSch40.stl, 1x Hub_1_inch.stl and 1x topsch40.stl. Two spider1_inch.stl are optional.

For 1 inch SDR21 PVC print: 3x stakefootsdr21.stl, 4x scruplugsdr21.stl, 1x Hub_1_inch.stl and 1x topsdr21.stl. Two spider1_inch.stl are optional.

For 32mm PN10 PVC print 3x stakefoot27_2.step, 4x scruplug27_2mm.step and 1x top27_2.step. Two spider32mm.step are optional. Metric files are in .step file format for easier editing.

Assembly

Cut three pieces of PVC pipe to 28” (70cm) for tripod legs. The remaining length of pipe forms the center mast. I used both hot melt glue and thickened cyanoacrylate superglue.  Both worked well.  Start with the threaded plugs and glue one into the end of each of the four pipes. Apply  glue to both the inside of the pipe and the plug. Insert the plug in the pipe and twist to spread the glue. Glue the top plug into the longest pipe. Note that the feet must be vertically aligned before gluing. First, firmly screw the three legs into the hub then apply glue to pipe and foot, insert foot into a leg, and align the foot so that the hole in the foot vertically.   Screw the parts together and insert the spike in the hole in the top plug.

Refer to  https://bit.ly/KJ6ERAntennasPrimer for superbly detailed instructions for rest of the build.

Notes

·       For storage and transport, there are optional springy clamps called spiders to help keep parts together. The spiders fit on the mast by friction. There are also holes in the ends of the screw plugs which allow the legs to be used for storage.  You can remove the spike from the feed point and gently slide into one of the legs through the hole in a screw plug.  Insert the antenna with attached feed point into one of the other legs for storage. 

·       If you use the red feed point note that the M10 tapped holes are not clearly marked. One is for the antenna and the other for the spike and counterpoise. Check continuity with an ohmmeter to make sure the center of the SO239 is connected to the antenna and the spike and counterpoise wires are connected to the outside of the SO239.

·       The tripod and antenna are quite light weight (about 3.5 pounds for SDR21) and top heavy. It could tip easily and damage the telescopic antenna. Use tent stakes or weights for stability. I reuse disposable 1 or 2-liter water bottles for weight. Make a two-link chain of zip ties, tighten one zip tie around the neck of the bottle, and leave the other one open to fit over one of the hooks on the tripod hub.