For reference, the power draw of the XS20G’s big brother, the KG-1000G, is as follows: @Idle @5w @20w @50w Conventional wisdom is to choose/design a power system so that the steady/continuous draw of the load is no more than 80% of the power system. For the 20w setting above, this would suggest a 7.5A supply.. However, this theory does not necessarily account for power-up surges which can be high. A 1.5-2x (and more) increase in power supply system capacity can at times be required. This would suggest a supply that can handle surges 9-12A (which would explain the 15A fuse). Most power supplies include some degree of surge capacity, which may be very well be 10% and more of their continuous rating. A well designed 10A continuous rated supply therefore would, in all probability, comfortably hand surges of 11A and greater. So assuming the KG-XS20G falls into the same 6A load draw as its big brother, a 10A + continuous rated supply would seem to be of sufficient size. While smaller sizes may also work well on receive, depending upon the quality of design and internal headroom of the supply and how long your transmission are, you may experience performance gremlins that have you scratching your head when transmitting. In the end, there is nothing wrong with the manufacturer’s 15A recommended power supply. It provides a very good and responsible safety margin. It also provides some extra power available for other things when you need it. Regards. Michael WRHS965 KE8PLM