The DC Low Frequency Laboratory provides measurement traceability of highest accuracy in South Africa in support of research, manufacturing, telecommunication, rail infrastructure, and aviation and electricity supply and installation industries traceable to SI units. We maintain an ISO 17025 compliant quality system accredited by South African National Accreditation System.
The NMISA’s Radio Frequency Laboratory provides measurement traceability for calibration of radio-frequency instruments used in the South African telecommunication, broadcasting and manufacturing industries, their suppliers, installers & maintainers for testing & measurement associated with imported RF equipment and components, locally manufactured RF instruments, performance testing of new and existing RF installations, and troubleshooting on installations.
The standards developed, maintained and disseminated by the Radio Frequency Laboratory include the national measurement standards for radio-frequency power, attenuation and impedance; and working standards for the calibration of RF power meters; attenuators; terminations; directional bridges and couplers.
Radio Frequency Power
Technical specifications based on RF power measurements are often the critical factor in the design, and ultimately the performance, of almost all Radio Frequency and microwave equipment. At NMISA two in-house developed national measurement standards are maintained, namely; a 50 Ω coaxial in 7 mm line systems from DC to 18 GHz and a 75 Ω coaxial in 7 mm line systems from DC to 800 MHz. Traceability is achieved via calibrated reference resistance standards and a DVM that is traceable to the national measurement standards of DC voltage and resistance. There are also five more commercially acquired national measurement standards that are maintained.
Radio Frequency Attenuation
The South African national measurement standard for attenuation is a WBCO piston attenuator system operating at 30 MHz. The working standard is a precision measuring receiver calibrated against the WBCO system. In calibration laboratories reference attenuators are employed to provide accurate low-level Radio Frequency power for the calibration of sensitive measuring instruments such as spectrum analysers, level meters and precision measuring receivers. Additionally, the reference attenuators are used to calibrate other attenuators, either directly or built into, for example, signal sources.
Radio Frequency Impedance
Radio Frequency impedance is an important parameter in radio frequency systems as it is a measure of how well systems connected by a transmission line work together with maximum Radio Frequency power transfer and the least amount of Radio Frequency power lost due to reflections of the signal.
The national measurement standards for Radio Frequency impedance are air-dielectric 50 Ω coaxial transmission lines. The impedance standard maintains equipment which ensures that telecommunication based on wireless or coaxial transmission line systems works without interruption and according to specification.