How to Install SMA Connectors

Updated February 21, 2017

Sub-miniature type A (SMA) connectors terminate coaxial cable for frequency applications from DC to 18 GHz. The threaded collar prevents signal leakage and reduces distortion for applications where the more common BNC type connectors fall short. Made from stainless steel or brass, SMA connectors provide a rugged connection suitable for industrial, military or aircraft applications. Installing SMA connectors requires precision workmanship due to their small size. However the basic procedures are the same as for BNC crimp connectors.

Slide the outer ferrule over the cable to be terminated. Also slide any rubber or plastic cable protection sleeve that may have come with the connector. Refer to the specific connector data sheet.

Strip off the outer covering with the cable strippers or a knife, trim the shield with the scissors and strip the centre conductor insulation back to the dimensions listed on the data sheet for your particular connector. Use a precision steel ruler to make the measurements.

Insert the centre conductor into the centre pin so it rests against the insulation. Place the pin in the smaller die of the crimping tool and squeeze the handles until they stop. Remove the pin from the crimping tool.

Insert the cable into the connector body with the inner ferrule under the shield of the cable. Slide the outer ferrule over the shield until it rests against the connector body. Place the outer ferrule into the larger die on the crimping tool, squeeze the handles until they stop, then remove the connector from the crimping tool.

Slide any protective sleeve over the crimped connection according to your particular connector data sheet.


For additional protection to the cable for connectors that don't come with a protecting sleeve, slide heat shrinkable tubing over the cable in the first step, then slide it over the finished crimp and shrink it with a hair dryer.


Be sure to use a crimping tool and dies specifically designated for SMA connectors. When trimming the shield with scissors, check closely for small wire strands that could cause a short.

Things You'll Need

  • Coaxial cable stripper
  • Knife
  • Scissors
  • Precision steel ruler
  • Data sheet for the SMA connector
  • Crimping tool with dies
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About the Author

Richard Asmus was a writer and producer of television commercials in Phoenix, Arizona, and now is retired in Peru. After founding a small telecommunications engineering corporation and visiting 37 countries, Asmus studied broadcasting at Arizona State University and earned his Master of Fine Arts at Brooklyn College in New York.