The SQUOD (selected quantile output device) is a simple scheme using rank-order statistics for estimating received signal strength, even following detection in a nonlinear (e.g., logarithmic) receiver. Numerical results are presented that show that for any number of steady sinusoids having incommensurable frequencies or randomly distributed mutually independent phases plus additive Gaussian noise, the populationp-quantile of the envelope can be used for estimating the rms value of the envelope with a maximum error of 0.797 dB for p = 0.5650. Analysis and numerical examples show the effects of using a finite-samplep-quantile.