KA9LXP's HF Antenna Mast Page

Build a Hustler-Compatible Mast for $5

I was flipping through some old 73 magazines I picked up at a hamfest and found an article by George Ewing, WA8WTE who described a method of making mobile antenna masts out of 1/2" copper water pipe. I didn't like some of the ways he did things, so I spent some time in the workshop and came up with the following plan to make my own, which I think looks better and has a fewer parts count. The materials listed here are enough to make 2 complete masts with very little left over. Total cost at the time of this writing was $8.75 from the local Home Cheapo store, less that $5 per mast. You may wonder, why build two and not just one? Simple. The pipe comes in 10 foot lengths which is enough to build two, and the extra parts to build the second one are only a couple of bucks. Once you've got all the tools dug out it only takes a few extra minutes to finish a second mast, so you can have a spare for when you back into the garage without taking the mast off first like I am prone to do.


BILL OF MATERIALS

QTY ITEM PRICE
1ea 10-foot piece of 1/2" copper pipe $4.69
4ea 1/2" copper end caps $.43ea
2pkg 3/8x1" fine thread hex head bolts $.78pkg/2
1pkg 3/8" fine thread hex nuts $.78pkg/6


Construction Details

Start by preparing the four bolts. Using a bench grinder or a file, round off the points of the head so that it will fit into the end caps.
Drill a 3/8" hole in the end of each cap. I found it easier to drill a 1/4" hole and enlarge it with a round file, but the method is up to to you.
Put the bolts through the end caps with the head inside the cap. Put a nut on the bolts finger tight to hold it in place. This also serves to keep the solder from leaking out in the next step.
Holding the bolt end with a pliers or vise, heat the bolt/cap assembly with a torch and fill the cap with solder, up to the level of the top of the bolt head. I used regular 63/37 solder and pipe soldering flux. There was no problem getting the solder to wet the steel bolt head to the copper cap. Repeat this process for the other three pipe caps.
With the nut still on the bolt and serving as a guide, cut the excess bolt length off flush with a hacksaw.
Remove the nut and dress the rough end with a file or grinding wheel. Repeat for the other three caps.
Cut the 10 foot pipe in half. Solder one of the cap/bolt assemblies to one end of each pipe, making sure the cap isn't crooked (it's easy to do). Follow usual pipe-soldering protocol, cleaning and fluxing, etc. Solder by heating the pipe, not the cap, and use heat only as long as necessary, otherwise you'll melt the solder already in the cap.
Using a tape measure, check the length of the pipe assembly both with and without the remaining cap/bolt assemblies in place. This is so you can determine how much pipe you need to cut off to get the desired 54-1/4" total length with the caps in place.
Cut the excess pipe off and solder the remaining cap/bolt assemblies on the two masts in the same manner you did the first ones.
That's it! Pretty simple, yet they work just as well as the real thing. Clean and paint as desired, or polish and use clear enamel (my preference). I found green Scotchbrite pads leave a nice finish for either painting or clear coating.


Installation Tips

Here are some photos of the completed mast on my XYL's car. I use short braces connected to the trunk lid to relieve the stresses where the mast threads into the mount. George, WA8WTE took care of the stresses by using a spring at the base, but I've found in practice that at highway speeds your antenna is anything but vertical with a spring. Either way, you need to support or guy the mast, especially with larger coils and longer whips.

Here is the KC5TZF mobile with the $5 mast
in place.
This is the trailer hitch mount I made, the
mast is supported with a stiff wire support
to the trunk lid.


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