Mike's Tech Blog

I needed to replace my old 2 Meter 1/4 wave vertical antenna for the 146 mHz. amateur radio band. The old one had lost its radials and I wasn't able to hit the various amateur radio repeaters around. So being one who likes to build antennas, here is what I came up with.

The Image below shows the materials you will need to build a 2 meter 1/4 wave vertical antenna for the 146 mHz. amateur radio band.

 Here is the list of parts needed to build a 2 meter vertical antenna:

• 3/4" PVC pipe - Length to suit
• 3/4" adapter 8xMPT
• 3/4"THD Dome Cap
• SO-239 connector
• 6ft. 14 GA Romex wire
• qty. 4 4-40 stainless screws
• qty 8 4-40 stainless nuts
• 50 ohm coax Length to suit

The first thing to do is to strip the copper wire out of the Romex wire sheath, then you will see a bare wire, a black and white wire. then strip off the insulation from the black and white wires as well. When you are finished, you should have three bare copper wires 6 ft. in length. 12 GA. wire might have probably been better, as it is bigger and stiffer, but I used what I had on hand. Cut 5 pieces of wire, each 22 in. long.

I then straightened each wire as best I could, but they still weren't straight. So I laid a piece of wood on the floor a bit longer than the wires, laid one wire on the board, and placed another board on top of the wire. Then I stood on the board and rolled the wire between the boards. This made them pretty straight without any of those annoying little kinks in the wire.

Next, I took the 3/4" THD Dome Cap and drilled a 5/8" hole through it. I started out with a 5/32" drill as a pilot hole, then finished off with a 5/8" speedbor spade bit. When you are done, it should look like the photo on the left.

Then I took 4 pieces of the copper wire, which will be used for the antenna's radials, and bent a little hook in one end, and then slid one 4-40 screw in the hook of the wire then crimped down the wire around the screw as seen in the photo  on the right.

Take the wire / screw assembly you just made, and put the screw into a corner of the SO-239 connector. Do this for each one of the corners of the SO-239 connector. When finished, it should look like the photo on the left. Make sure the wires are sticking out perpendicular to the center of the SO-239 connector, like in the photo.

After you tighten down the screws, its a good idea to add a second nut and tighten it down as well. this will help this joint from loosening up in the wind.