If you have neither oscilloscope, spectrum analyzer nor modulation monitor, but do have a soldering iron, you can use the Breakaway Calibration Tool to achieve acceptable calibration.
This tool will guide you through:
- Using a regular sound card to create a makeshift oscilloscope
- Use the parallel (printer) port on your PC to generate perfect squarewave
- Calibrate the makeshift oscilloscope with this squarewave
- Calibrate Breakaway Broadcast's output with this oscilloscope.
Download the tool here.