10.7MHz IFTs for FM

[transistor495]

Does anyone have an idea of the basic structure of a 10.7MHz IF Transformer in a tuned transistor stage of a receiver.

I want to know:
1. Does it have a ferrite core/slug core.
2. Approximate wire diameter and no. of turns for primary and secondary.
3. Does it have an inbuilt cap like an AM IF Transformer.

 

[RadioRon]

I looked up some typical parts for 10.7 MHz IF use. For example, the Toko
154AC-470052N0 ( **broken link removed** ) is a metal can with an adjustable "core", probably made of ferrite or powdered iron. It appears that the core is actually not just a core but a small core and a large bobbin, both ferrite, with the bobbin designed to adjust up or down on the outside of the coil. There is at least one capacitor inside, in parallel with primary or secondary. Might be one on each, I can't tell.

Wire diameter is probably quite small magnet wire, I'm guessing based on past experience, but likely in the range of 28 to 34 AWG. Number of turns is tailored to provide the specified transformation ratio (you can buy many different ratios) while also resonating the inductance with the parallel cap.

 

[transistor495]

Thanks RadioRon. I'll check it out. Actually I want to wind it over a 455KHz one for the specified inductance and turns ratio. Have no idea about the parallel cap. Not much sure whether will be a successful attempt or not.

 

[Nigel Goodwin]

I would suggest the core material will be completely different.

Why not just get a ready made transformer from an old radio?.

 

[Mikebits]

I agree with Nigel. Making your own would be futile. Better to buy a premade one.

 

[Nigel Goodwin]

I agree with Nigel. Making your own would be futile. Better to buy a premade one.

It's not inductance that is futile, it's RESISTANCE that is futile!

 

[ericgibbs]

RESISTANCE that is futile!

So whats Conductance,?

 

[mvs sarma]

Does anyone have an idea of the basic structure of a 10.7MHz IF Transformer in a tuned transistor stage of a receiver.

I want to know:
1. Does it have a ferrite core/slug core.
2. Approximate wire diameter and no. of turns for primary and secondary.
3. Does it have an inbuilt cap like an AM IF Transformer.

Now a days you get ceramic ones with the needed bandwidth and it helps to go ahead without hassles.
10.7 MHz IF Filter Modifications

above link gives additional info.

 

[audioguru]

The cheap FM scanning radio from The Dollar Store uses a 70kHz IF that uses an active filter using opamps.

 

[transistor495]

I've salvaged some brown colored IFT's from old receivers. I think it's 10.7MHz types. It has only one parallel cap.