On Sun, 24 Oct 2010 20:23:29 -0700 (PDT), Tom Horne
wrote:

I have read that the presently available 300 ohm ladder line is
unsuitable to use at some amateur radio frequencies because of it's
construction and the losses caused by skin effect in the copper coated
steel construction.

Hi Tom,

You really have to question your judgment of the source of what you
are reading. The rationale of losses caused by "skin effect", and for
the very reason of it being copper is a perversion.

I have been using a Terminated Folded Dipole in a
flat top configuration as my HF antenna at home.

Revisiting this issue of line loss (however it was derived) in the
face of the loss in the terminating resistor of your antenna has got
your expectations inverted. Consider line loss in the tenths of dB to
1dB and the antenna loss easily double that worst figure (if not
triple or quadruple).

Having recently
acquired an Icom AH-4 Antenna Coupler I am considering converting it
to a simple folded dipole,

Folding it adds no virtue.

feeding it with 300 ohm ladder line to
match it's nominal impedance from the coupler.

If it has a nominal 300 Ohm Z, then use a conventional BalUn and coax
solution.

However, methinks you are going to treat this antenna as Z=300 at all
frequencies. No way.

I know your sure that
there is a question in here someplace so is there better quality 300
ohm window line available that is entirely stranded copper in it's
construction?

Consult the wireman.com.

73's
Richard Clark, KB7QHC