Case study, how many turns are needed?
Updated: Sep 10, 2020
Number of turns left = number of turns right.
L value: XL value @ 1 MHz
1 turn: 0,02 mH 125 Ohms
2 turns: 0,06 mH 377 Ohms
3 turns: 0,17 mH 1.068 Ohms
4 turns: 0,32 mH 2.010 Ohms
SWR 1 turn
SWR 2 turns
SWR 3 turns
SWR 4 turns
Conclusion: More turns result in a better return loss at low frequencies
More turns result in a worse return loss at high frequencies
For return loss 2 turns looks the best of both worlds.
Insertion loss 1 turn
Insertion loss 2 turns
Insertion loss 3 turns
Insertion loss 4 turns
Conclusion: More turns result in a better insertion loss at low frequencies
2 and 3 turns gives the best results for insertion loss at high frequencies
3 turns gives the best result at low and high frequencies.
Smith chart 1 turn
Smith chart 2 turns
Smith chart 3 turns
Smith chart 4 turns
Conclusion: Also here it is clearly visible that 2 turns have the flattest swr curve.
At 15 MHz 2 turn showed an impedance of 45 ohms + j9 ohms.
See below, with 45 pF we can compensate the inductive behaviour.
I have used 39 pf (closest value in my junk box)
The results are truly fantastic: