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How to Mod an A99 Antenna for 10 Meters

The Antron A99 antenna, also known as the Solarcon A-99, is an inexpensive and reliable antenna that is sold for use with CB radios. However, ham radio enthusiasts have found that this antenna provides efficient reception of signals and frequencies on the 10-meter amateur radio band, a band that is often hard to access with a regular ham antenna. Since the antenna is intended for the 11-meter CB band, cutting the mast improves the reception on the 10-meter band. Once you trim the mast, you adjust the tuning rings of the A99 antenna for optimal reception.

Things You'll Need

Pipe cutter
Wire clippers
Measuring tape or ruler
Marking pen
SWR meter

Instructions

- 1
  Disconnect and dismount the A-99 antenna. If it is a newly purchased A-99 unit, assemble but do not permanently mount it.
- 2
  Pull the protective cap off the top of the antenna mast. Measure 10 inches down along the mast from the top and mark the spot with a pen.
- 3
  Position the blade of your pipe cutter at the dot and screw its clamp down so that the blade is held flush to the mast without crushing it. Rotate the cutter until you cut through the fiberglass mast and pull the cut section of mast away.
- 4
  Clip the copper wire in the center of the antenna mast with a pair of wire cutters so that it is the same height as the mast. Slide the protective cap over the cut top end of the antenna.
- 5
  Plug the antenna lead into an SWR meter and place your antenna in an upright position on a stand or clamp it temporarily to a wall. Check your ham radio transceiver owner's manual or local radio club information to find out the ideal SWR reading for 10-meter band reception in your area.
- 6
  Rotate the tuning rings at the base of the mast until the SWR reading matches your ideal reading. Trim an additional two inches off the mast according to the instructions in Steps Three and Four if you cannot get a low enough reading at the present length of your antenna. Rotate the tuning rings again and trim in two-inch increments until you get the reading you desire. Replace the protective cap each time you finish trimming.
- 7
  Remove the lead from the meter, connect the antenna to your ham transceiver and test its reception and transmission on frequencies in the 10-meter band. Trim away more of the mast in two-inch increments and re-tune accordingly if your reception is poor.

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