I remember thinking (I was only a teenager at the time) that to promote the station with slightly the wrong frequency seemed a bit strange - 730 instead of 729 - presumably just because 729 is not an American channel and just about all the jocks were American ? Had the low power tests after they lost the balloons been on 558 the signal would have been even weaker than it was on 729 as the efficiency would have been even worse on the lower frequency. It was said in interviews that the day when they just put out Beetles music all day they were running about a kilowatt into a wire antenna that was more horizontal than vertical with poor matching (SWR) and giving a poor groundwave. They used crazy high modulation levels to give the impression is was stronger than it was.