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9:1 balun for ladder line

Dec 13th 2022, 14:28


Joined: Aug 24th 2019, 14:12
Total Topics: 0
Total Posts: 0
Hello - I am looking for a diagram for a three wire wrapped ferrite donut to make a balun. I have searched the internet but unfortunately it has only turned up baluns for long wire or end fed dipoles. I am looking for a schematic for a 9:1 as I am feeding my dipole with home made ladder line and then transitioning to coax to enter the shack. Should I ignore that the schematics state long wire or end fed or is there a specific diagram for the interconnection of the windings?
Thanks and 73.
Dec 13th 2022, 14:32


Super Moderator

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
9:1s for long wires and end feds are meant to connect unbalanced coax feeders to unbalanced antennas. Connecting them instead to a balanced feeder may unbalance the feeder and result in feedline radiation.

If you want to feed a center fed dipole with window line, one of the better combinations is a 130 ft center fed dipole feeding 100 ft of 450 ohm window line going to a 1:1 balun and a short length of coax to an antenna tuner.

I have found it difficult to find a combination that will work on all bands.
Changing the window line or dipole length will allow the tuner to work on a finicky band but may result in difficult tuning on another band.

Zak W1VT
ARRL Senior Lab Engineer
Dec 14th 2022, 18:26


Joined: Aug 24th 2019, 14:12
Total Topics: 0
Total Posts: 0
Thank you Zak. Much appreciated.

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