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"Balun" is a portmanteau of "balanced" and "unbalanced". Anything made to interconnect a balanced and unbalanced load can be called a balun.

A common-mode choke (like a length of coax wound over a ferrite ring) works as a balun because it inserts a high impedance in the common-mode without affecting the differential-mode. By action similar to a voltage divider, most of the current will then favor the differential-mode.

Typically the differential-mode impedance will be something like 50 or 75 ohms: it's simply the design feedpoint impedance of the antenna. A decent choke can provide a common-mode impedance of 4000 ohms. Because the differential-mode impedance is so much lower, the common-mode current will be very low, practically negligible.

A common-mode choke like this accomplishes the objective of converting between a balanced and unbalanced load. It's easy to manufacture, has low loss, high power handling, can be effective over a wide band, is inexpensive, and works even if the "balanced" load isn't quite perfectly balanced.

This is by no means the only way to make a balun, but for HF and lower this particular design has a lot of advantages, making it very popular. It is very much a proper balun, and with an appropriate design and application is can be a superb solution.

"Balun" is a portmanteau of "balanced" and "unbalanced". Anything made to interconnect a balanced and unbalanced load can be called a balun.

A common-mode choke (like a length of coax wound over a ferrite ring) works as a balun because it inserts a high impedance in the common-mode without affecting the differential-mode. By action similar to a voltage divider, most of the current will then favor the differential-mode.

Note that a common-mode choke is not quite the same thing as an RF choke. An RF choke is more or less just an inductor, albeit one with the intended application of blocking RF current. A common-mode choke is a four-terminal device which looks like an RF choke to common-mode current, but to differential-mode current it looks simply like a transmission line.

^{simulate this circuit – Schematic created using CircuitLab}

Typically the differential-mode impedance will be something like 50 or 75 ohms: it's simply the design feedpoint impedance of the antenna. A decent common-mode choke can provide a common-mode impedance of 4000 ohms. Because the differential-mode impedance is so much lower, the common-mode current will be very low, practically negligible.

A common-mode choke like this accomplishes the objective of converting between a balanced and unbalanced load. It's easy to manufacture, has low loss, high power handling, can be effective over a wide band, is inexpensive, and works even if the "balanced" load isn't quite perfectly balanced.

This is by no means the only way to make a balun, but for HF and lower this particular design has a lot of advantages, making it very popular. It is very much a proper balun, and with an appropriate design and application can be a superb solution.

"Balun" is a portmanteau of "balanced" and "unbalanced". Anything made to interconnect a balanced and unbalanced load can be called a balun.

A common-mode choke (like a length of coax wound over a ferrite ring) works as a balun because it inserts a high impedance in the common-mode without affecting the differential-mode. By action similar to a voltage divider, most of the current will then favor the differential-mode.

Typically the common-mode impedance will be something like 75 ohms, that of a resonant dipole. A decent choke can provide a common-mode impedance of 4000 ohms. Because the differential-mode impedance is so much higher, the common-mode current will be very low, practically negligible.

A common-mode choke like this accomplishes the objective of converting between a balanced and unbalanced load. It's easy to manufacture, has low loss, high power handling, can be effective over a wide band, is inexpensive, and works even if the "balanced" load isn't quite perfectly balanced.

This is by no means the only way to make a balun, but for HF and lower this particular design has a lot of advantages, making it very popular. It is very much a proper balun, and with an appropriate design and application is can be a superb solution.

"Balun" is a portmanteau of "balanced" and "unbalanced". Anything made to interconnect a balanced and unbalanced load can be called a balun.

A common-mode choke (like a length of coax wound over a ferrite ring) works as a balun because it inserts a high impedance in the common-mode without affecting the differential-mode. By action similar to a voltage divider, most of the current will then favor the differential-mode.

Typically the differential-mode impedance will be something like 50 or 75 ohms: it's simply the design feedpoint impedance of the antenna. A decent choke can provide a common-mode impedance of 4000 ohms. Because the differential-mode impedance is so much lower, the common-mode current will be very low, practically negligible.

A common-mode choke like this accomplishes the objective of converting between a balanced and unbalanced load. It's easy to manufacture, has low loss, high power handling, can be effective over a wide band, is inexpensive, and works even if the "balanced" load isn't quite perfectly balanced.

This is by no means the only way to make a balun, but for HF and lower this particular design has a lot of advantages, making it very popular. It is very much a proper balun, and with an appropriate design and application is can be a superb solution.

"Balun" is a portmanteau of "balanced" and "unbalanced". Anything made to interconnect a balanced and unbalanced load can be called a balun.

A common-mode choke (like a length of coax wound over a ferrite ring) works as a balun because it inserts a high impedance in the common-mode without affecting the differential-mode. By action similar to a voltage divider, most of the current will then favor the differential-mode.

Typically the common-mode impedance will be something like 75 ohms, that of a resonant dipole. A decent choke can provide a common-mode impedance of 4000 ohms. Because the differential-mode impedance is so much higher, the current where will be very low, practically negligible.

A common-mode choke like this accomplishes the objective of converting between a balanced and unbalanced load. It's easy to manufacture, has low loss, high power handling, can be effective over a wide band, is inexpensive, and works even if the "balanced" load isn't quite perfectly balanced.

This is by no means the only way to make a balun, but for HF and lower this particular design has a lot of advantages, making it very popular. It is very much a proper balun, and with an appropriate design and application is can be a superb solution.

"Balun" is a portmanteau of "balanced" and "unbalanced". Anything made to interconnect a balanced and unbalanced load can be called a balun.

A common-mode choke (like a length of coax wound over a ferrite ring) works as a balun because it inserts a high impedance in the common-mode without affecting the differential-mode. By action similar to a voltage divider, most of the current will then favor the differential-mode.

Typically the common-mode impedance will be something like 75 ohms, that of a resonant dipole. A decent choke can provide a common-mode impedance of 4000 ohms. Because the differential-mode impedance is so much higher, the common-mode current will be very low, practically negligible.

A common-mode choke like this accomplishes the objective of converting between a balanced and unbalanced load. It's easy to manufacture, has low loss, high power handling, can be effective over a wide band, is inexpensive, and works even if the "balanced" load isn't quite perfectly balanced.

This is by no means the only way to make a balun, but for HF and lower this particular design has a lot of advantages, making it very popular. It is very much a proper balun, and with an appropriate design and application is can be a superb solution.