How to Make an RF Signal Generator Signal Transmission Line

Radio frequencies (RF) are any electromagnetic waves that oscillate at a rate between 3 kilohertz and 300 gigahertz (a hertz is once oscillation per second). Transmitting signals in the RF range becomes difficult because of interference, both from sources external to the signal and the signal itself. RF transmission lines must be carefully made to ensure that interference is at minimum. This is very important, because interference can ruin the integrity of a signal and result in a failed transmission.

Things You'll Need

  • 50 Ohm coaxial cable
  • Coaxial cable stripping tool
  • 2 BNC connectors
  • BNC crimping tool
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Instructions

    • 1

      Cut a length of coaxial cable. For RF work, the shorter the better. Find out the shortest possible length for whatever application you have in mind, and cut the wire to that length. For example, if you intend to attach a signal generator to an oscilloscope, find the minimum distance required to connect the two devices and cut the coaxial to that length.

    • 2

      Open the coaxial stripping tool, which opens like a pair of scissors. Slide the length of coaxial cable into the stripping tool. The stripping tool has teeth on one end only. This is the side that you place the cable in.

    • 3

      Place the cable in far enough that the other end reaches the edge of the stripping tool but does not extend out from the tool.

    • 4

      Close the coaxial stripping tool. Rotate it around the cable once or twice. As you do this, the cutting edge is slicing through the insulating sheath that covers the wire.

    • 5

      Open the coaxial stripping tool and remove the wire from it. Pull the insulating sheath off by gently tugging at it. The copper mesh underneath is now exposed.

    • 6

      Repeat steps 2 through 4 for the other end of the coaxial cable, so that it is stripped on both ends.

    • 7

      Identify the two pieces of the BNC connector. One piece is a connector, and the other piece is a crimping sleeve. The connector has a small metal probe sticking out of one end, and the sleeve is a hollow metal column that is tapered on one end.

    • 8

      Place the sleeve on one end of the coaxial wire, placing it so that the narrower end goes onto the wire first.

    • 9

      Bend the copper mesh back over the top of the sheath. An inner wire is now exposed.

    • 10

      Strip off the insulation from this inner wire using the technique covered in steps 2 through 4. Cut only half of the total exposed length of wire. A solid copper wire is now exposed.

    • 11

      Take the other piece of the BNC connector and thread the solid copper wire into the end opposite the metal probe.

    • 12

      Slide the sleeve piece of the BNC connector up the wire until it overlaps with the other BNC piece. The copper mesh will bend upward as you do this and may stick out of the seam between the two BNC pieces. You can trim this later.

    • 13

      Place the BNC connector into the crimping tool, choosing the larger of the two holes. Place this over the wider end of the BNC sleeve.

    • 14

      Firmly squeeze the crimping tool to press the BNC sleeve into the coaxial cable.

    • 15

      Place the BNC connector into the crimping tool again, this time choosing the smaller of the two holes. Place this over the narrow end of the BNC sleeve.

    • 16

      Firmly squeeze the crimping tool again. The BNC connector is now connected to one end of the coaxial cable.

    • 17

      Repeat steps 6 through 15 to attach the BNC connector to the other end. You have now created a transmission line capable of reliably transmitted RF frequencies.