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balum needed on EFHW?

Nov 4th 2021, 12:29

KK4LYQ

Joined: Dec 26th 2017, 06:25
Total Topics: 0
Total Posts: 0
I have a 67' end fed wire with a 34' counterpoise.
my transmitter is a 40m OHR kit
my MFJ 259B indicates a very high SWR
MY ZM-2 tuner will only bring it down to about 1.7

my friend insists I need a 9:1 balum but I cant find any documentation to support his advise

Ladies and Gentlemen: I have no wish to be rude but please don't respond unless you have first hand experience.

Thank you
Jan 21st, 08:31

N1LOU

Joined: Mar 18th 2020, 15:25
Total Topics: 0
Total Posts: 0
You could use a 9:1 balun, those are common on end fed half wave wires. But you don't need to if your tuner gets to a 1.7:1 match, which really isn't that bad. I am not sure I would use a balun and a tuner. Just out of curiosity, Why end fed and not a dipole? Both an end fed half wave and a dipole require the same height when oriented horizontally. Switching to a dipole configuration will let you eliminate the tuner and the balun, as well as the counterpoise and will give you a much more efficient antenna. You will lose RF energy to heat in either a balun or a tuner. If you have the antenna oriented vertically, you lose radiation efficiency with just a counter poise (as opposed to a robust radial field). I would invest in some coax and turn that wire into a dipole, but that's just me.

Jan 21st, 14:36

AI4BJ

Joined: Sep 2nd 2003, 12:14
Total Topics: 0
Total Posts: 0
From the equipment that is mentioned, I would guess that the OP is not talking about a permanent, home installation. Although dipoles are more efficient, end fed antennas are often more practical for portable ops, especially in areas where there may only be a single suitable support. I also agree with you that if the tuner can produce a 1.7:1 match on its own, I would dispense with the balun.

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