Elecraft's AT1 41dB step attenuator allows you to choose a whole range of levels below 50 uV with the XG3. Ron AC7AC -----Original Message----- The XG3 could be ten band 160 through 6M accurate 50 uV and 1uV source. Actually I might want something other than 1 uV as that is an awkward value between S3 and S2. AE6WA Mike Scott Tarzana, CA