On May 28, 10:16*am, Sonny Hood wrote:
* *I have an efficiency question concerning feed lines. *My present
system is RG-8X to my 75 meter inverted vee which is about 85 feet
away from the shack. *I propose to replace some 88 feet of coax with
300 ohm window ladder line that is inserted into the coax run with 4:1
baluns to match the coax on each end. *Also at the feed point of the
antenna switch from a voltage balun to a current balun (ferrite chock
type). *By my calculations with a 98 watt generator I will increase
the power to the load by about 11-20 watts and with a 985 watt
generator, 117-210 more watts will reach the load. *Figuring
theoretical total system (A) against total System (B) or by just the
difference in the 88 feet of ladder line versus coax. *What do you
think the increase will be?

I think you left out the losses in the balun. With a kilowatt even a
large (by ham standards) balun will get very warm if you leave the key
down... my guess is it's not quite as much as you're saving but
comparable. It all amounts to 10%, and that's such a tiny fraction of
a S-unit.

Now, if your antenna were an incredible mismatch to coax to begin
with, then ladder line makes good sense. Say you want to use your same
inv-V on 40M, then you'd run ladder line all the way to your tuner and
be in fat city.

Tim N3QE