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Old January 17th 06, 12:18 AM posted to rec.radio.amateur.antenna
Cecil Moore
 
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Default Dipole and Ladder Line Matching

jimg wrote:
Hi. I've heard and read some about ladder line and dipoles.
So what is the basic configuration look like? My impression is
the set-up starts with either a balanced tuner with 400 ohm output
or a 50 ohm tuner with a 4:1 balun to the 440ohm ladder line. The
ladder line then runs to the dipole and that's pretty much about it.

So my EZNEC on my future backyard Vee shows about 60ohm which is about
a 12:1 mismatch at the antenna feedpoint! So do I have something wrong
in the basic config? Or do you all put a balanced impedance
transformer up at the antenna feedpoint?


Here's what I did and it works very well.

http://www.qsl.net/w5dxp/notuner.htm

An SWR of 12:1 on ladder-line is acceptable but where did that value
come from? 440/60 is 7.3:1. And your 440 ohm ladder-line (Wireman #554)
is probably closer to 360 ohms.
--
73, Cecil