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450Ω vs 600Ω ladder linr to feed loop antenna using 4:1 Balun

Apr 17th 2017, 18:36

WA2FTV

Joined: Mar 3rd 2012, 03:12
Total Topics: 0
Total Posts: 0
Hello Everyone,

I reside in an apartment (courtyard style) with no access to outside (i.e. no balcony).

I am considering installing a large loop antenna and feeding it with either 450Ω or 600Ω ladder line from a 4:1 balun. This in turn would be fed by an antenna tuner.

Other than losses, is there any advantage of 450Ω or 600Ω ladderline?

Please advise.

Thank You and 73s

Cedric
WA2FTV
Apr 21st 2017, 12:10

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
No, the only advantage of using 450 ohm ladder line is lower losses. Typically there aren't any matching issues using 50 coax. Nor is there a particular common mode advantage, as loop itself often provides a degree of common mode rejection.

In order to provide a lot of common mode rejection, two cores are typically required. Many designs use only one to cut costs, sacrificing common mode performance.

Zack Lau W1VT
ARRL Senior Lab Engineer

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