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Old May 28th 08, 03:50 PM posted to rec.radio.amateur.antenna
Highland Ham Highland Ham is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 250
Default Ladder line Vs. Coax

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?

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Why not replace the complete coax feeder with twin lead feeder (if you
can keep it away from soil and/or metal) , and use a matching box
directly accepting the twin lead feeder ( without ferrite type balun),
be it 300 or 450 Ohms or approx 600 Ohms ladder line ?
It will improve efficiency and above all make the antenna multi-band.

Frank GM0CSZ / KN6WH