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Author Topic: Balun question  (Read 1597 times)
KA3VEZ
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Posts: 92




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« on: August 03, 2011, 07:19:40 PM »

Correct me if I am wrong but I saw somewhere where you can use a balun(not sure if it was a 1:1 or 4:1) to be used for a long wire setup with a tuner of course.  I heard that on the center conductor side of the balun you put up whatever length you can and the other end would go to a ground rod.  Any thoughts on this?  Thanks.

~Kirk, KA3VEZ
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AC5UP
Member

Posts: 3836




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« Reply #1 on: August 03, 2011, 07:55:47 PM »

A true longwire is multiple wavelengths long and can be matched without a tuner. Typical impedance will be in the ballpark of 450 ohms.

An end fed wire needs a superior ground comprised of ground rods and radials. The matching device can be a wideband 9:1 unun or a tuner and is often a trouble spot... The typical unun used is an autotransformer type with three windings on a toroid. They work well at the lower frequencies but start to go deaf above 5 MHz or so. Been there, done that. A 130' wire with a 9:1 unun makes an outstanding AM BCB or 160 Meter RX antenna but for general SWL use you'd be much better off with a 66' doublet.

As for a TX antenna I've never had good luck with an end fed wire and that might be because I never put a serious ground system under one.

If you can manage an autotuner at the feedpoint of a longwire you should have better RX results on the higher bands than I did. But, for TX? The efficiency of the antenna will be in direct proportion to the quality of the ground system under it. End fed wires involve much more shovel work than you'd suspect at first glance and IMHO there are easier ways to get a signal in the air...........  Wink
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KB3LIX
Member

Posts: 1106




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« Reply #2 on: August 03, 2011, 07:55:54 PM »

From what you describe, I would just lose the balun and
go with an unbalanced feed from the tuner.
Center conductor to the wire and the frame of the tuner to
the ground, plus string out some additional wire
on the ground side to act as a counterpoise.

NO COAX, NO Twin Lead, straight from the SO-239
conector on the rear of the tuner.

Cross your fingers, and hope for the best.
« Last Edit: August 03, 2011, 07:57:54 PM by KB3LIX » Logged
W8JI
Member

Posts: 9304


WWW

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« Reply #3 on: August 04, 2011, 05:28:37 AM »

Correct me if I am wrong but I saw somewhere where you can use a balun(not sure if it was a 1:1 or 4:1) to be used for a long wire setup with a tuner of course.  I heard that on the center conductor side of the balun you put up whatever length you can and the other end would go to a ground rod.  Any thoughts on this?  Thanks.

~Kirk, KA3VEZ

Try reading this:

http://www.w8ji.com/long_wire_antenna.htm
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