"running at full tilt, the two-tuber would have a whopping(!) 3 db. advantage over the single 4-1000A! That's a full half S-unit difference" That's a true statement. Interesting that in today's world of inflated S-meter readings with circa 2004-2007 receivers it may be impossible to double the power and get just a half an S-unit meter change. 73, Ken W2DTC