Topband: Open wire line vs. Paralleled coaxials.

[Rick Karlquist]

Rudy Bakalov wrote:

> the impedance of a single cable of the same type. However, the power
> rating will be about the same as for a single cable, since the current-
> carrying ability of the center conductors has not changed. However, in

No.  The power handling capability is doubled.  The insertion loss
is unchanged.

> The losses on a coax are because of dielectric losses. But here you are

Dielectric losses in coax are neglgible on 160 meters.  Nearly all
loss is conductor loss.

> not using the shield as RF conductor, so the PE of foam dielectric is
> working in a different manner.  The return goes on the other center
> conductor and not the shield. Loss figures are between those of coax and
> those of "real" open wire lines; they are closer to the open wire and not

Again, the dB/100 ft loss of two coax lines in a balanced configuration
is exactly the same as one coax line in an unbalanced configuration,
assuming the shields are tied together, and assuming a matched load.
If unmatched, losses in general tend to go up.

>
> Rudy N2WQ

Rick N6RK