DIY: Build a portable CB base antenna

This is the final entry of a 3-part article submitted by the folks at Centerfire Antenna. I highly recommend reading Part Two before starting this  project. You can view part 2 HERE.

This is a photo tutorial on assembling a portable dipole antenna for use with a CB radio. These  antennas  will extend the range of a hand-held radio. They can be used indoors or outdoors and make an excellent antenna for those that may not be able to install a permanent outdoor antenna. They can be suspended from a tree, rafter or gable.

You will need the following tools:

  • Wire cutters and strippers
  • Razor knife
  • Tape measure
  • Cable tie installation tool
  • Soldering gun or iron
  • Solder suitable for electronics

You will need the following supplies:

  • 18′ or more RG8X coax cable, one end should have the proper connector to attach to your transceiver.
  • 2 pcs of 10-12 Gauge stranded copper primary wire x 106″ long (These wires will be the dipole’s “elements”.
  • 3″ of heat-shrink tubing, 1/4″ diameter
  • 1 can of Liquid Rubber or Plasti-Dip
  • 8″ of trimmer line or heavy fishing line
  • 5 small  cable ties.
  • 2 complete spade connectors (male and female)

RG8X coax was chosen for this project because it has a copper shield and a stranded copper center conductor making it ideal for soldering. This antenna could be built without the spade connectors, just add 1/2″ to the 106″ wire length. For what it’s worth, we recommend using the spade connectors. If this antenna is pulled on or tripped over, the antenna will (ideally) separate at the connector instead of breaking a soldered joint.

Strip 3/4″ of outer insulation from the antenna  end of your RG8X coax. Separate the shield from the center conductor and twist tightly.

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Crimp and solder the male spade connectors onto the coax. Seal the coax by dipping this end into the Plasti-Dip or Liquid Rubber. It may be necessary to put more than one coat on. Set aside and let it dry completely.

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Take one of your 106″ Dipole “elements” and strip 1/2″ from  one end. On the same end, measure back exactly 4″ and remove about 3/4″ of the insulation. Strip 1/4″ of the insulation of the other end of the element.

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Loop the element as shown and use one of the cable ties to hold it in place while it is soldered.

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Slide a 1 1/2″ piece of heat-shrink tubing onto the element and install it as shown.  Lightly solder the female spade connector onto the wire, DON’T crimp this connector yet. Repeat the last three steps on the other 106″ element.

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When your  coax is dry, cut and peel the excess sealant from the spade portion of the connector. Make a loop from trimmer line or heavy fishing line and attach it firmly with several cable ties.

Install an element on each spade connector and suspend the antenna about 10 feet off the ground. Tie out the elements in an Inverted Vee configuration. Attach the antenna to your SWR meter or analyzer and check SWR. You should have an almost perfect match on channel 20 and less than 1.5:1 on channels 1 and 40. You may need to spread or close the Vee slightly to achieve the best SWR. If you have an SWR over 1.5:1 on channel 40 and less on channel 1 you may need to shorten the antenna if moving the elements doesn’t help. If so, unsolder the the female connector and clip 1/2″ from the length of the element and check SWR again.

When the SWR is satisfactory, crimp and fully solder the female connectors.

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Update: You can purchase this dipole by special order from Centerfire Antenna. Please contact them via their website by clicking  HERE.

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