Hi, I was monitoring the frequency of 155.8425 and am not sure if its FM or FMN. I'm not really familar what the difference is or what they both mean but seem to come in clear set on either one. I think if the frequency would be 155.840 or 155.845 it would be set under FM but I noticed most VHF frequencies with a odd ball number in the database are set to FMN. The true freq is 155.8425 and still come in with no difference in signal on 155.840 or 155.845. Also does this apply to UHF frequencies too?