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A Cheap Feedpoint for Verticals

Building a single vertical or an array? Do you have a plan for cleanly terminating the feedline at the base of the antenna? Is there a small circuit you’d like to protect from the weather at the base of the antenna? Here’s a solution I came up with over the past year as part of building three transmit 4-squares and an active receive array that’s currently in the works.


Hello Lowe’s

I went to the electrical department at the local Lowe’s see if they had anything that might work. And here’s what I found.

This box has three holes. They are drilled and threaded to connect electrical conduit. The holes are conveniently located for our connection requirements . . . don’t you think? The kit also comes with threaded metal plugs to seal up unused holes.

It turns out that the hole diameter is just right for a flange-mounted SO-239. I just lay the SO-239 in the hole and mark where I need to drill for #6 mounting screws. My approach is to drill and tap the wall of the box itself for the screw. You could also drill straight through and use nuts and lock washers,

SO-239 mounted in one of the conduit holes.

For the connections to ground and to the hot element, I use a hardware stack of screw, nut, washers and a wingnut mounted in one of the conduit holes with a plug. For ground, I use a metal plug. Insulating plugs are also available as an option. I picked up a handful of them and I simply drill a hole for a #8 or #10 screw and use the wingnut stack there for the hot connection. Works great.

Wingnut hardware stack mounted on an insulating plug for the hot connection to the antenna element.

Lowes also sells many flavors of covers for these boxes. For my application, a blank cover works fine.

Blank cover installed on box. Notice seal provided to keep moisture out.
Details of internal construction for a simple pass-through box. Note the convenient ground screw.

All the hardware combined comes in at about $9 including the SO-239 connector. Not bad!


We built a 20m 4-square using these feedpoint boxes.

K1IR 20 Meter 4-Square
SWR is great!

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