[TowerTalk] Routing Ladder with Parallel Coax?
k0dan at comcast.net
Sun Apr 6 13:21:21 EDT 2014
P.S. Two lines of RG-11, 75/2=37.5 ohms. Two lines of RG-8, 50/2=25 ohms.
Not much of a difference to worry about.
If you don't tie the coax shields together you basically have parallel
feedline at higher Z all the way through. The goal is to preserve the 400 or
600 ohm ladderline impedance all the way through. The coax is gonna effect
that, but two 70 or 50 ohm lines in parallel is a bigger Z-bump than if you
just leave the shields floating.
Also, if you're using a T or Pi network tuner, it's not truly balanced.
Should work except with most extreme Z's, but another variable to keep in
At least that's been my experience, YMMV.
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