Do the NSI SGH NRL curves include estimates of the SGH losses?
No, the NRL calculated gain curves are calculated directivity and do not include ohmic or VSWR losses. Data curves supplied with each SGH represent directivity based on the actual horn dimensions, and not gain. However, since gain assumes a perfect match we do not need be concerned about mismatch, only losses in the horn itself and this is in general in the order of 0.1 dB.
