Adjusting Sweep time

RF Explorer handles sweep time refresh and RBW selection automatically, as described in the User Manual.

There are some situations where a manual tuning of the sweep time is required, and can be easily achieved in RF Explorer using the Iterations option in the Attenuator Menu.

There are two typical scenarios where this is required:

  • Detecting fast signals: Many modern transmission protocols use frequency hopping techniques (LTE, Bluetooth, ZigBee, etc) that prove difficult to detect in one single sweep. By selecting Calculator:Max mode, you can easily select how many consecutive sweeps will be accumulated by selecting Iterations value. For instance, an Iterations:002 value means 2 consecutive sweeps will accumulate on screen, effectively duplicating the sweep time. The RF Explorer unit allows for up to 28 consecutive sweeps to be accumulated, being that the equivalent to a sweep 28 times slower than realtime. If 28 sweeps is not enough for certain signals, you can use the Calculator:Max Hold which effectively uses an infinite accumulator, which can be reset anytime in the Spectrum Analyzer screen with the RETURN screen. By using the Max Hold mode you effectively control how long the sweep accumulates, some site surveys have the Max Hold mode accumulating for hours to detect sporadic intrusive signals.
  • Averaging noise: Noise is random by nature and can be easily removed from measurement by averaging sweep samples. Some spectrum analyzers define this as “video average”. By selecting Calculator:Average mode, you can easily average samples from consecutive sweeps so the random nature of noise cancels itself. Selecting a correct Iterations value for the Average mode is a compromise between sweep speed and noise cancellation. In most cases, 4-6 accumulated sweeps is enough and still shows a good refresh rate, but every environment is different so start with Iterations:005 and increase it if noise is still visible.

Due to internal memory constrains, the RF Explorer device is limited to 28 internal accumulative iterations max. With a standard sweep time of 100-200ms, 28 iterations mean tuning capabilities for up to 2.8-6 seconds accumulated sweep time.

However, this limitation is not such when connected to a PC: the RF Explorer for Windows software allows for 10 million iterations to be used, with the advantage of saving the realtime capture on file disk and allowing post-processing using different Iteration values in order to easily isolate the signal of interest.