Most organic radicals will have a g-value of approximately 2. This corresponds to a field for resonance of approximately 3480 Gauss at a microwave frequency of 9.8 GHz. Performing wide scans maximizes the probability of finding the EPR signal. Use an appropriate microwave power level . Using more microwave power does not necessarily result in a more intense EPR signal.
Saturation can occur.
Organic radicals in non-viscous solvents or many samples at cryogenic temperatures are susceptible to saturation effects. Try running the EPR experiment at several different power levels. Use appropriate signal channel parameters . The parameters should be optimized for the type of signal to be expected. If you get a straight noiseless line for a spectrum, the signal channel may be overloaded.