1:1 Balun Options
Steve G3TXQ has done a lot of research on the use of different types of cores and air cored ferrites, the results can be seen on the chart below. For a link direct to his page please click here
The two types I refer to within this site are the 8T RG58 on FT240-43 but substituting the RG58 for RG142. Also the 6 x FB-31-1020 on RG213. There are many other ways listed on Steve's list below and more info can be found on his site.