Spectrum Master™ User Guide : Initial Startup : Set the Span
 
Set the Span
Spectrum Analyzer and Interference Analysis Modes
1. Press the Span main menu key or press the Freq main menu key followed by the Span submenu key.
2. To select full span, press the Full Span submenu key. Selecting full span overrides any previously set Start and Stop frequencies.
3. For a single frequency measurement, press the Zero Span submenu key.
Note 
To quickly move the span value up or down, press the Span Up 1‑2‑5 or Span Down 1‑2‑5 submenu keys These keys facilitate a zoom‑in, zoom‑out feature in a 1‑2‑5 sequence.