The AAA-1 can be used to measure the field intensity. Calibrating the loop needs very specific measurement equipment which is an expensive or time consuming task. Fortunately the AAA-1 loop mode has very predictable antenna factor AF which can be calculated with the help of the spreadsheet. The only hardware we need is a receiver with well calibrated S-meter. Direct sampling SDRs are very suitable for this purpose. Download the new updated version of loop calculations spreadsheet WLoop_calc_v12.xls http://www.lz1aq.signacor.com/docs/w-loop-calc-v12.xls .