Howdy, I`ve had a 930 for a while,my second, it seems to me I remember some mod that allowed the addition of a SSB filter if the auxiliary slot had the CW filter.I`ve got the Inrad booklet on the 930 but, there is no mention of it. I remember it used the filter switch in SSB mode to select it. I may have this confused with the 940 .Is anyone familiar with this? Thanks , Jeff / N4YU