-177dBm /Hz at 300 deg SSB phase noise is correct, not because AM/ FM but Single Sideband Energy . In my last QEX paper I showed the measured AM and FM levels and how to calculate them. 73 de Ulrich xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxx In a message dated 8/11/2016 9:00:11 P.M. Eastern Daylight Time, mfeher@eozinc.com writes: That is interesting. We always used -174 and not -177 as it was concluded that at those low levels AM and PM noise are not discernible, so, the total noise density per Hz was -174. This must be relatively new since I worked in industry. We had a bunch of PhDs from Lincoln helping as well and they always used -174. This sounds like one of those instrument manufacturers gimmick to make the numbers look better :). Your last statement is why I started to question the claims initially. - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -----Original Message----- From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of John Miles Sent: Thursday, August 11, 2016 7:57 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] State of the art of crystal oscillator measurements -177 = the -174 dBm/Hz SSB thermal noise floor at 25C, less 3 dB to account for the usual assumption that half of it is AM, half PM. dBm/Hz is obviously equivalent to dBc/Hz for a 0 dBm carrier. Anyone who claims to measure noise in a 1 Hz bandwidth below -177 dBm/Hz at room temperature is either doing something wrong somewhere, or doing something amazing somewhere. -- john, KE5FX Miles Design LLC > -----Original Message----- > From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Mike > Feher > Sent: Thursday, August 11, 2016 4:15 PM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] State of the art of crystal oscillator > measurements > > That is why I asked what the Po was. Where did the 177 come from? L(f) > is single sided. This is not my first "rodeo" in these matters. 73 - > Mike > > Mike B. Feher, EOZ Inc. > 89 Arnold Blvd. > Howell, NJ, 07731 > 732-886-5960 office > 908-902-3831 cell > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.