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Everyone knows that balun stands for Balanced to Unbalanced and is an AC electrical device which can be used as an impedance transformer and is also used to convert an unbalanced or single ended AC system to a balanced or differential AC system and vice versa. A common example of usage of this device is to enable an unbalanced coaxial transmission line to be ...


5

The roofing filter is the filter through which the first IF must pass. The roofing filter is an IF filter, specifically the first one. AB4OJ provides a block diagram: As for why it's called a "roofing" filter, Elecraft suggests it's about protecting the subsequent stages from spurious signals: The term "roofing filter" has most often ...


3

A Guanella balun or transformer is constructed so that there is effectively no magnetic flux in the core(s). There is of course some, otherwise it wouldn't have any inductance, but the common-mode current is effectively suppressed by the common-mode impedance. The core remains cold, even at the highest operating power. By contrast the Ruthroff transformer ...


3

A Guanella balun is a transmission line device based on a design described by Gustav Guanella in a 1944 paper in Brown, Boveri & Company's internal journal Brown Boveri Review. The paper was called "New method of impedance matching in radio-frequency circuits", or possibly "Novel matching systems for high frequencies". Possibly these ...


2

A Guanella balun is a device which consists of some series and/or parallel combination of transmission lines wound on ferrite cores which simultaneously presents a high impedance to common-mode current and provides a transformer-like impedance transformation between input and output. Guanella refers to Gustav Guanella. Guanella held numerous patents, but the ...


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I can agree with the answers above, but I see radio Amateurs just coiling up the coax feed cable at the base of the antenna, without the ferrite ring and this does choke off the RF in both directions (No transmitted power or received signals). I tried this with a half-wave long wire on a field day and demonstrated that with the coli present we could not be ...


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