# Lost & Found

Some random electronics related stuff that you may find useful. Will be expanded continuously.

• ### A dBm conversion table

• A table to convert between dBm, power, and voltage in 50 Ω systems. From −130 dBm to +30 dBm. Print it out and pin it up at your bench. The table is in pdf format. Created with a GNU Octave script and LaTeX.

• ### Nomogram for uncertainty in return loss measurements

• Gives the worst case upper and lower uncertainty bounds in a return loss measurement due to an adapter of specified return loss between DUT and directional coupler (or measuring bridge). Also applies if the directivity of the directional coupler is used in place of the return loss of the adapter. Here is another version with different scaling. Generated by this script for GNU Octave.
Example: A DUT with a return loss of 30 dB is measured through an adapter with a return loss of 40 dB (or with a directional coupler with 40 dB directivity). Then the uncertainty bounds of the measurement are read off to be $30\,{\rm dB}+2.4\,{\rm dB}$ and $30\,{\rm dB}-3.3\,{\rm dB}$.