155.805 is Channel-1, but this is the frequency we put in our scanners because it is the output of the repeater. The Rio unit keys up, their radio actually transmits on 153.965 and the repeater instantly rebroadcasts the transmission on the .805. We listen to the output of the repeater because it is usually the stronger signal for us to hear. If you look on the Sandoval County DB page, underneath the NM map, there is a drop down box that says, "Input frequency" hidden. Since we usually do not listen to the input of the repeater, the default in the DB is to hide them. If you click the drop down box to "shown," the DB will populate any input frequencies in the DB.
Also, if you are unsure how repeaters work, check out the Wiki page: