This ER summarizes the results of the 2022/2023 survey conducted jointly by RTCA Special Committee-242 and EUROCAE Working Group-124 (SC-242/WG-124) on the applicable RTCA and EUROCAE published standards for Radio Frequency (RF) performance that could be used for spectrum compatibility analysis with external systems. The process involved existing RTCA Special Committees and EUROCAE Working Groups, plus additional experts if the responsible committees for certain documents were no longer active. The surveys and the resulting questions raised are intended to inform the spectrum guidance document that RTCA and EUROCAE are developing, and therefore this report does not provide any guidance of its own for the development of future aviation standards.