Here is 4:1 Transformer for HF long wires (New Nov 09)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
THIS IS NOT A BULAN!
An auto-transformer may well make matching a long wire possable on AUTO ATUs that do not have a good impedance range. (e.g. only for SWRs of 3:1)
It is possable to rewire/switch a bulan to do this.
At this ratio the ferrite only has to handle 50% of the RF power!
Turns Ratio 5:10 giving a Z ratio of 1:4
In general a transformer turns ratio is square root of the Z/Z.
So for 600Ω to 50Ω that is √600/50 = √12 = 3.46 or 2:7 3:11 4:14 5:17 turns etc.
An autotransformer tapped system where the lower turn is a tapping of the total also the lower turns should be 2x thicker!
┌──────┐
│ │6 17
│ │┌┐┌┐┌┐┌┐┌┐┌┐┌────o
│ ├┘└┘└┘└┘└┘└┘└┘ 600Ω
50Ω Txr │ ▀ │ │▒▒▒▒▒▒▒▒▒▒▒▒▒
Unbalanced └─┬─┘ │▒▒▒▒▒▒▒▒▒▒▒▒▒
│ │┌┐┌┐┌┐┌┐
│ └┘└┘└┘└┘└┬────────o
│ 5 0 │ _│_
└───────────────┘ ///