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Author Topic: tuners  (Read 437 times)
N0EGS
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Posts: 14




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« on: September 06, 2008, 07:35:41 AM »

would i be better off using a l-match or t-type transmatch as i am replacing my coax feedline with open wire line?my ant is a full wave loop.
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KE4NU
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« Reply #1 on: September 06, 2008, 08:25:14 AM »

Hello, I put up a 75 meter horizontal fullwave loop I tried both ways:(1)bring the ladderline in the shack hooked to a johnson matchbox and (2)brought down to a 4to1 balun then about 12 ft of rg8X to the shack to a tuner. I saw no difference on any band in signal strength either on transmit or receive. So, I sold the matchbox and use the balun to coax, it works outstanding for me.
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WV4L
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« Reply #2 on: September 06, 2008, 08:59:59 AM »

Same here. 40m horizontal Delta loop fed with 600 Ohm ladder line to a 4:1 balun with about 14ft of RG8 to the antenna switch in the shack. Works for me.
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K1BXI
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« Reply #3 on: September 06, 2008, 09:24:45 AM »

 "my ant is a full wave loop."..... What frequency is it a full wave? And how long is the feed line?  

If you are going to use it on all bands, a T match tuner with a 1:1 balun would be a good choice.

John.....K1BXI
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K1BXI
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« Reply #4 on: September 06, 2008, 09:28:47 AM »

Make that a 1:1 current balun.........

John.....K1BXI
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W8JI
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« Reply #5 on: September 06, 2008, 09:52:47 AM »

You can have, depending on open wire line length, a pretty high impedance at the rig when you change to open wire line.

Say the loop has a impedance of 100 ohms. With 450 ohm ladder line, the impedance at the tuner can be anything from 100 ohms to 2000 ohms.

It all depends on the feedline length.

So sometimes you wind up being lucky with the right feedline length, and sometimes unluckey with the wrong feedline length.

I'd use a T network tuner with a 1:1 current balun as suggested.

73 Tom
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