----- Original Message -----
From: "Gary Hoffman" <ghoffman@spacetech.com>
> ((Some content deleted))
>
> Your point is that the better the feedline, the lower the losses, and open
> wire feedline is best.
>
> All true and I totally agree.
>
> The point is, if you use the very best feedline you can, you can limit
> losses and have the tuner in the shack and all will be well.
>
> 73 de Gary, AA2IZ
>
Actually if you have a very-low impedance load, a low
impedance line is better. Open wire line made from say #14
copper has more loop conductor resistance per unit length than
a piece of Andrew LDF4-50 hardline, but average current for
moderate to high impedance loads is lower on the O.W.L due
to its higher characteristic impedance, so the O.W.L. wins
out in these situations. For very low impedance loads, the
current maximum in the standing wave on the line get so large
that hardline wins out due to the fatter conductors and despite
its lower characteristic impedance. That's why the ARRL's
TLW program (author N6BV) is so handy. You can plug in
different numbers for load impedance and then try different
transmission lines and compare losses very quickly. It's been
a real eye opener for me.
73 de Mike W4EF...........................................
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