ARRL Technician Practice Exam

Which type of conductor is best to use for RF grounding?

1. Round wire

2. Flat strap

3. Twisted pair

4. Solid bar

The correct answer is: Flat strap

Using flat strap for RF grounding is advantageous for several reasons. First, flat strap provides a larger surface area in contact with the grounding medium compared to round wire. This increased surface area helps to minimize inductance and resistance, which is particularly important for high-frequency RF signals. The low inductance means that the ground system can effectively dissipate RF energy, reducing the potential for unwanted interference or signal degradation. Additionally, flat strap can be easier to work with when creating connections to other grounding components, such as ground rods or grounding plates. It can conform better to surfaces, ensuring a more secure and reliable connection. Ground configurations using flat straps tend to be more effective in addressing common mode currents which are a concern in RF applications. In contrast, round wire, twisted pair, and solid bar conductors do not provide the same benefits in terms of surface area and inductance. Each of these alternatives has its own applications, but when it comes to RF ground systems, flat strap is recognized as the superior choice for achieving optimal performance.