Why is the winding shorted on all of these balun schematics?

[Opcom]

These are the common 75 Ohm coaxial -to - 300 Ohm unbalanced matching devices that are (or were) used with TV sets, FM receivers, and any other purpose.

Just about every schematic of these shows one of the windings to be shorted, that is grounded at both ends.

I do not understand why this is good or correct. Anyone know about this mystery?

hundreds are shown this way
https://www.google.com/search?q=schematic+of+a+75+to+300+Ohm+TV+set+balun&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiX1-3L9LrtAhVEcq0KHcz6C1UQ_AUoAXoECBAQAw&biw=1920&bih=919

[W1RKW]

http://www.ham-radio.com/k6sti/balun.htm

Scroll down about 2/3 of the way. you'll see some of the same schematics for 75 to 300 ohm baluns and explanation for the short or no short.

[ka1bwo]

These are the common 75 Ohm coaxial -to - 300 Ohm unbalanced matching devices that are (or were) used with TV sets, FM receivers, and any other purpose.

Just about every schematic of these shows one of the windings to be shorted, that is grounded at both ends.

I do not understand why this is good or correct. Anyone know about this mystery?

hundreds are shown this way
https://www.google.com/search?q=schematic+of+a+75+to+300+Ohm+TV+set+balun&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiX1-3L9LrtAhVEcq0KHcz6C1UQ_AUoAXoECBAQAw&biw=1920&bih=919

Pat the schematics are incorrect. Were the transformers are connected in series should not go to ground

[DMOD]

These are the common 75 Ohm coaxial -to - 300 Ohm unbalanced matching devices that are (or were) used with TV sets, FM receivers, and any other purpose.

Just about every schematic of these shows one of the windings to be shorted, that is grounded at both ends.

I do not understand why this is good or correct. Anyone know about this mystery?

hundreds are shown this way
https://www.google.com/search?

q=schematic+of+a+75+to+300+Ohm+TV+set+balun&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiX1-3L9LrtAhVEcq0KHcz6C1UQ_AUoAXoECBAQAw&biw=1920&bih=919

Pat the schematics are incorrect. Were the transformers are connected in series should not go to ground

These transformers are based on "Transmission Line Transformer" theory.

http://k5tra.net/tech%20library/RF%20transformers/Transmission-Line%20Transformers.pdf

http://www.introni.it/pdf/Amidon%20-%20Transmission%20Line%20Transformers%20Handbook.pdf

https://highfrequencyelectronics.com/Jan06/HFE0106_TraskPart2.pdf

https://www.markimicrowave.com/assets/appnotes/balun_basics_primer.pdf

http://www.introni.it/pdf/Amidon%20-%20Transmission%20Line%20Transformers%20Handbook.pdf

https://www.amazon.com/Transmission-Line-Transformers-Jerry-Sevick/dp/1884932185

Phil

[Opcom]

Thank you all, I had not given these little baluns much thought though I had opened many.