dbc dbm

dBm and dBc are completely different so there is no 'conversion' between the two.

dBm - indicates the power measurement relative to 1 milliwatt. 0 dBm means no change from 1 mW, i.e. a power of exactly 1 mW. 3 dBm means 3 dB greater than 0 dBm. dBm is the relative difference to a fixed reference power of 1 mW.

dBc ? indicates the power relative to the power of the main carrier frequency; typically used to describe spurs, noise, channel crosstalk, and intermodal signals which may interfere with the carrier. dBc is the relative difference to an arbitrary reference power level, the power level of the carrier frequency.

well, you could convert between them for a specific application. If you had a spur that was -50 dBc, and the carrier was at +10 dBm, then the spur would also be at -40 dBm.

Both of RealAEL and biff44 are right.dBm is compared with 1mW(dBm=10log(Power/1mW),and dBc is compared with carrier power(carrier(dBm)-power(dBm)).

I think RealAEL is wrong and biff44 is right.

everything RealAEL said is correct. I just gave a numerical example to further clarify his point.

Update: I think RealAEL is wrong and biff44 is wrong.

If you know that both are wrong, then I conclude that you own the truth. Right ?
May we share your knowledge ?

LvW is right.

No

I think RealAEL is right