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1-8 of 8 messages
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Page 1 of 1
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ladder line polarity????
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by K1JGK on October 26, 2009
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hi gang
got my full loop up.80-10 meters
feeding it with ladder line
?? does it make diffrence in rx or tx
if u switch feed line output at tuner teminals ???
change them from one side to other?
thanks
jeff k
k1jgk
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RE: ladder line polarity????
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by N3OX on October 26, 2009
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"does it make diffrence in rx or tx
if u switch feed line output at tuner teminals ???
change them from one side to other? "
If it matters you need a better balun to make your balanced output. Unfortunately since not all baluns are great it might matter. It has nothing to do with the line itself, but with the physical arrangement of the antenna and the type and performance of the balun.
Nothing you can do but try it. Ideally it won't change a thing. If you don't notice a difference when you do it, that's good.
73
Dan
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RE: ladder line polarity????
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by K0ZN on October 26, 2009
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No, there is no "polarity" on ladderline, assuming your tuner has a BALANCED output, which can be accomplished by either an internal balun in the unit, an external balun, or the tuner has a balanced design.
If fed with a balanced source, this is why balanced parallel transmission line works... it has BALANCED, EQUAL and OPPOSITE current in each wire, thus, essentially cancelling radiation. If, for some reason, you do not have equal and opposite current in each conductor, then the line WILL radiate. This is also why it is so important to keep ladderline reasonably straight and away from other conductive objects as they can upset balance in the line. You NEVER want to coil or have a "rat's nest" of ladderline: cut it to the length you need.
Connecting ladderline to the output of an UNbalanced tuner will not work as well and there likely will be some line radiation and interaction with the ground system. i.e. a Balun IS needed in that case.
Because, essentially, the energy field is "around" ladderline, there IS a shock and RF burn hazard (which is truly DANGEROUS at legal limit power levels) with ladderline. You don't want people or pets to come in contact with it when you are transmitting. In a system where the SWR is high (multiband antennas) the voltage on ladderline can run into the thousands of volts in some cases.
Coax is a different game and there is or can be "polarity" (it is not really "polarity" in that sense) that must be observed in certain situations.
Bottomline: ladderline is good stuff, but it has to be understood and respected.
73, K0ZN
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RE: ladder line polarity????
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by WA3SKN on October 27, 2009
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A loop is a balanced antenna.
Ladderline is a balanced feedline.
It will make no difference if you turn the leads over, you are working with AC and a single element here.
73s.
-Mike.
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RE: ladder line polarity????
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by K1JGK on October 27, 2009
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thanks gang
i see no diff if i switch output termenals
just checking. loop works great. i think
its up 30ft and works europe on 40m at 0200
20 and 17 very good ,80 and 40 up to 2000miles
thanks
jeff k
k1jgk
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RE: ladder line polarity????
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by AC5UP on November 7, 2009
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Just don't cut the red wire
____________________
You didn't get the memo?
Violet is being substituted for red until 12/21/2012, then alizarin crimson becomes the new age red.
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