600 Ohm ladder line

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Eric Zerkle:
I am buying some 600 ohm true ladder line from W7FG "True Ladder Line and Antennas" in Oklahoma. Has anyone used their products? I have heard some OT'ers talk about using the 600 Ohm line and how well it works, so I thought i'd buy some and replace my 450 Ohm and see how well it will work for me.

Phil Chambley, Sr.:
Unless you have some sort of very sophisticated single-frequency application, you won't see any difference at all.

Save your money.

Phil C. Sr.

Owen Duffy:

True ladder line, indeed!

As far as I can glean, it is specified as Zo=600ohm, VF=0.91, #16 diameter conductors, and the pic shows the centre to centre spacing at about 95mm.

No loss specs offered.

Using TWLLC (http://www.vk1od.net/calc/tl/twllc.htm), it looks like Zo might be more like 550 ohms if the other parameters are correct. It doesn't matter much, unless you were depending on Zo for some kind of matching scheme.

TWLLC suggests matched line loss at 10MHz of 0.32dB/100m, but again, that doesn't mean much in typical applications, because they are not usually matched.

If you used a half wave of it to feed a 70+j0 load at 20m, loss would around 0.15dB, whereas Wireman 551 for the same scenario would be around 0.19dB... not a lot in it in that scenario.

If it is 'truly' less affected by water, that would be an advantage is some locations.

I don't really understand what is 'true' about it.


Floyd Sense:
I've had some of the W7FG ladder line installed for a couple of years now and it's withstood heavy winds and high UV with no problems.  I suspect it's referred to as "true" ladder line because it's not the plastic "window" line that's commonly referred to here as ladder line.  

John C Allen:
It's nice that their line is "true."  Wouldn't want to use false line, would we?

For most applications, I doubt that you will see any difference.  One possibility is that, if you are building matching stubs, the different velocity of propogation might call for slightly different stub lengths.

73 de John/AD7WN


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