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