[Elecraft] Off topic feedline question

[Wes Stewart]

You are mistaken. 25' of ladderline is only about a tenth of a wavelength and 
does not invert impedance. I suggest you download Dan's TLDetails program: 
http://ac6la.com/tldetails1.html and play with it.  Put in what you think, or 
have measured, the feedpoint Z is then select one of the Wireman ladderlines and 
see what happens as you change the length.

You may find some data on zip cord as feeders, but I would avoid them like the 
plague, particularly as you are trying to solve a problem that doesn't exist.

Wes  N7WS


On 11/7/2017 7:08 AM, Michael Blake wrote:
> My 80M antenna is a low, loaded dipole fed with balanced window line.  As the 
> center impedance is  low the high impedance window line tries to invert the 
> impedance to a much higher value.  The feedline is only 25' long and 
> terminates in a 1:1 balun which is then connected to a remote autotuner via 24 
> inches of 9913F.
>
> The question is:
>
> Has anyone run any RF loss tests on the commonly available 12 gauge clear PVC 
> insulated "speaker" wire.  The impedance would be quite low, probably in the 
> 90 ohm range, and world certainly handle the applied power (500 watts) but I 
> have not been able find any information regarding RF loss.
>
> Michael Blake
> k9jri at mac.com