[Premium-Rx] Re: Premium-Rx digest, Vol 1 #41 - 1 msg The 'Ideal' Logwire (NewRadioChap@aol.com)

[AKnott at WTD71.de]

I got some experience with broadband transmission line BalUns and UnUns,
even QRO-versions. Take a look at those two famous book Jerry Sevick W2FMI
wrote: "Transmission Line Transformers" and "Building and Using BalUns and
UnUns". I think that one will be able to build a transformer of 50:200Ohm or
even 50:450 Ohm for 10Khz to 10MHz with stacked 1:1 transmission line BalUns
of 100-Ohm-line or 150-Ohm-line wound around different selected ferrite
materials in each "leg" to keep the decoupling stable. The effort would be
relatively high: for example 18 different coils on ferrite (three times a
leg of four differnt toroids and pot cores). This kind of transformer would
just be able to serve for reception because the ferrites would have to have
more volume for transmission purposes and therefore the line would become
too long for the upper edge (10MHz)! A network analyzer with the capability
to measure S-parameter or just forward transmission would help very much.
Anyway, even such a transformer will NOT be able to match a wire at all
frequencies between 10kHz and 10MHz! DD3LY