For special purposes (like broadcast listening, hunting for "DX" utility stations), the main frequency scale may show the frequencies of 'points of interest'.

(VLF spectrum/spectrogram with 'Radio Station' display)
The frequency list can be loaded from a textfile; the format (and where to find suitable databases) is described in frequencies/readme_freqlist.txt .
There is a only small 'default' list contained in the Spectrum Lab installation archive. To use a different list (for example the EiBi shortwave broadcaster list), enter SpecLab's main menu and select Options ... System Settings ... Filenames and Directories ... Radio Station List .
Doubleclick into the edit field to open a fileselector. Then select the file type (SL can load frequency lists from textfiles or semicolon-separated "csv" files).
The colour of the radio station display (for the spectrum graph and the main frequency scale) can be modified through the main menu, too: Select Options ... Display Colors and Fonts ... Radio Station Frequency Markers .
See also: Spectrum Lab's main index , programmable frequency markers , spectrum displays , main frequency scale .