Comparative measurement between 61, 67 and 73 material.
- xtgaby
- Apr 14
- 1 min read
Updated: May 19
I made a 1:1 transformer with
3 turns primary and
3 turns secondary.
The coil value of 3 windings of the 61 material is 13.2 μH @ 1 MHz.
The coil value of 3 windings of the 67 material is 4.7 μH @ 1 MHz.
The coil value of 3 windings of the 73 material is 300 μH @ 1 MHz.
The impedance of the coil with 61 material @ 1.8 MHz = 149 Ohms.
The impedance of the coil with 67 material @ 1.8 MHz = 53 Ohms.
The impedance of the coil with 73 material @ 1.8 MHz = 3400 Ohms.
The results:
61 material:
67 material due to the low impedance we have a bad SWR @1.8 MHz:
73 material:
IL 61 material:
IL 67 material:
IL 73 material:
Compensation for 14 MHz
I did a new measurement to be able to compare before and after compensation.
Before:
Impedance @ 14.1 MHz = 53 = J30 Ohms.
Calculation of the compensation with the use of a smith diagram:
I have placed an SMD capacitor of 91 pF at the input.
In detail:
After:
Due to the high inductive behavior, I reduced the number of windings to 2 and then to 1 respectively.
Two turns P and S:
One turn P and S:
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