I dedicated today evening to experimentation with coils for the IF 9MHz As I found in the first attempt the inductance of the primary, that should be about 3.13 uH to be able to resonate at 9MHz in parallel with 100 pF, it appears instead to be 2 uH and a little bit with all the core inserted. This result was obtained by taking the number of turns shown in the mounting plane. Looks like that the value of 6 +6 turns for the primary and 4 turns for the secondary shown in the diagram are completely incorrect.
They were probably copied from reference tables for IF transformers Toko 10K series that apart from being bigger are likely to have a higher core permeability.
Trying to wrap different amount of turns and then measuring the inductance with all the core inserted, I managed to get a quite accurate value of permeability (I hope) around 10.5.
With this data I calculated the number of turns required to grow to about 4 uH with all the core inserted so as to have a wide margin of adjustment around the 9 MHz IF.
The calculation gave 17 turns. I rounded to 18 turns for the primary and 6 for the secondary coil.
The final resulting transformer is shown in the figure below, it’s very challenging to wrap the coils and then solder the wire to the pins. Here is the result.
The inductance value, as shown int the following 2 pictures, stay within the range I were calculating. 4.5 uH with full inserted core and 1.5 uH without core.
Right now I wrapped just 2 transformers and before to solder them I will test with 100 pF capacitor between the primary coil and checking with the oscilloscope the resonance at 9 MHz.