When measuring a downconverted signal on an oscilloscope after a heterodyne mixer (e.g. ZEM-4300+ or ADE-11X+), the level read on screen is not the actual RF input level — it is reduced by the mixer's conversion loss, which varies with frequency. This calculator interpolates the conversion loss from the mixer's typical performance table and reconstructs the real RF signal level.
Enter the mixer type, target RF frequency, any external attenuation, and the value measured on the scope (dBm, Vpp or Vrms) to get the equivalent LO frequency, interpolated conversion loss, and the actual signal level and voltage at the source.