5 Mistakes To Avoid When Building An RF System
When building an RF communication system, patience and attention to detail is key. Even the smallest misalignment in a system can have a much greater impact than you might expect. From choosing suitable components to overlooking important factors like antenna coverage and VSWR, getting the small details right matters. Connectivity leaves no room for error.
1) Assuming higher antenna gain always equals better performance
Antenna gain is most certainly an important factor that must be considered when choosing your antenna. However, this cannot be solely relied upon to aid your selection as you must also consider other factors like your required coverage. A more optimal approach is to overlook all specifications and evaluate whether they will work together in your system. For example, you should match the antenna's gain and radiation pattern to your required coverage area. This will ensure your system is fully aligned, allowing the antenna to perform to the best of its ability.
2) Ignoring VSWR
When the impedance of a load (e.g. an antenna) does not match the characteristic impedance of the transmission line/source, your system has an impedance mismatch. In turn, this caused a high VSWR and RF energy to be reflected back towards the transmitter as a reflected wave. The mistake in this scenario is to overlook the high VSWR or not measuring it entirely. A much better approach is to regularly measure VSWR to ensure any impedance mismatch is kept to a minimum. Furthermore, you should investigate high VSWR when it occurs and attempt to find the root of the cause, helping to prevent it in future. Cutting corners will lead to worsened antenna performance, meaning this factor must not be overlooked.
3) Choosing the wrong cable
Cabling almost acts as the middleman between a transmitter and the antenna, connecting them both and allowing RF signals to be transported between one another. This is why choosing the right cabling solution for your system is pivotal. This decision should not be down to simple factors like price or diameter alone. Whilst these should be considered, there are a much wider range of factors everyone should take note of when selecting RF cable, such as frequency, length & flexibility requirements, insertion loss, power handling and the surrounding environment. Flexible cabling may be required in applications where space is limited, whereas cables with high power handling or fire retardant features may be needed in larger, more hazardous environments.
4) Overlooking connector compatibility
This cabling cannot be implemented without high-quality RF connectors, which join coaxial cables and transmit high-frequency signals with minimal loss or reflection. However, simply assuming connectors will fit and perform effectively just because they look similar to the cable end is not sufficient. The best approach in this case would be to look at the full specification list and consider factors like the connector's type, gender, impedance, and frequency rating. This helps to fully ensure that a connector is right for your system and cabling setup, allowing the entire system to run as expected.
5) Treating components in isolation
The common mistake in this case is assuming the antenna alone determines your system's performance i.e. good antenna = good communication system. Whilst a high-quality antenna is highly beneficial to your system and allows you to reach your required coverage area, you must consider the complete path that RF signals take to reach this point. A signal will travel through coaxial cable, through any filters to remove unwanted signal, combiners to merge the signals into a single path, or distribution components to take the signals to their desired location. Put simply, RF signals take a long, complex path to reach the antenna, meaning all components must be considered and monitored just as much as the antenna.
The key takeaway? Effective RF system design goes beyond choosing individual components. It's about ensuring they all work together for the intended application. If you would like to learn more about the path that RF signal take to reach the antenna,
click here.
21/10/2026
