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Many of my articles call for finding the complex permeability of a ferrite components from manufacturer’s data.

Let’s explore an example used in a recent article, Another small broadband RF transformer using medium µ ferrite core for receiving use – 50:450Ω.

The core used was a Fair-rite ferrite core of #43 material, and the magnetising impedance of a 5t winding needed to be found.

Above is a chart from Fair-rite’s catalog. Permeability is a complex quantity and is frequency dependent. One could scale from the graph, the values for µ’ and µ” at the frequency of interest. Continue reading Online calculator of ferrite material permeability interpolations

A simplified design for small broadband RF transformers using medium µ ferrite core for receiving use. The specific application is an impedance transformer for a nominally 450Ω antenna to a 50Ω receiver input. Intended frequency range is from 0.5 to 15MHz.

The characteristic of typical medium µ ferrite mixes, particularly NiZn, are well suited to this application.

This article continues with the design discussed at BN43-2402 balun example, but using a BN43-202 with 5t primary and 15t secondary for a nominal 1:9 50:450Ω transformer (though at high ratios, the transformation is only nominal).

Lets consider a couple of simple starting points for low end and high end rolloff. Continue reading Another small broadband RF transformer using medium µ ferrite core for receiving use – 50:450Ω

A simplified design for small broadband RF transformers using medium µ ferrite core for receiving use. The specific application is an input transformer to a nominally 2kΩ receiver at around 9MHz (a panadapter).

The characteristic of typical medium µ ferrite mixes, particularly NiZn, are well suited to this application.

This article continues with the design discussed at BN43-2402 balun example, but using a 2t primary and 16t secondary for a nominal 1:64 50:3400Ω transformer (though at high ratios, the transformation is only nominal).

Lets consider a couple of simple starting points for low end and high end rolloff. Continue reading Another small broadband RF transformer using medium µ ferrite core for receiving use – 50:3200Ω