Which frequency standard is commonly used as a time base standard by field technicians?

The Rubidium Standard is commonly used as a time base standard by field technicians due to its balance between performance, size, and cost. Rubidium frequency standards are highly stable and provide precise timekeeping, making them suitable for various applications, including telecommunications and navigation systems.

Rubidium oscillators are often used for applications where portability and reasonable cost are important factors. They offer a good trade-off between accuracy and size compared to other standards. Rubidium technology is based on the hyperfine transitions in Rubidium-87 atoms, allowing it to achieve high frequency stability.

In contrast, while the Cesium Standard is known for its exceptional stability and is considered the primary frequency standard (with a defined second) used in national timekeeping laboratories, it is generally larger and more expensive than Rubidium standards, making it less practical for field technicians. Quartz standards, while widely used due to their availability and lower cost, do not match the accuracy and stability of Rubidium or Cesium standards. The Hydrogen Standard, although used in some applications, is not as common for field technicians as Rubidium due to its complexity and size.