In a 1:1 current balun, you would want the Z of the line in balun to be the
same as the transmission line i.e. 50 ohms not some Z in the middle. If it
is different it will do an impedance transformation of the load Z based on
the Z of the line in the balun, its length and frequency. In a 4:1 current
balun the Z should be about 100 ohms. I don't know if zip cord or what ever
you call it makes a 50 ohm open wire line. I think the spacing is to large.
I know that #14 enameled wire close spaced does make a 50 ohm line. Anyway
the difference in loss between #18 wire and RG-400 due to IR drop in the
length of wire in a balun is too small to worry about.


John Passaneau, W3JXP
Penn State University



"Reg Edwards" wrote in message
...
Reg, is that superior to coax wound on the same toroid?
I use RG-400 teflon coax for my baluns.
--
73, Cecil http://www.qsl.net/w5dxp

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Just compare the coax inner conductor diameter with the 18-gauge wire of
the
zip-cord. Conductor resistance is inversely proportional to wire
diameter.

Furthermore, the transition from 50-ohm to open-wire line is less abrupt.
In theory, the impedance of the line wound on the transformer should be
intermediate between coax Zo and open-wire Zo.

On the other hand, the difference in loss due to either effect is hardly
detectable. The length of line involned is too small to make much
difference. I shouldn't bother changing the design.

I can't imagine how the coax got in there in the first place.
---
Reg, G4FGQ