I have two trees about 135 feet apart and about 55 to 65 feet tall. I have been trying to determine which kind of wire antenna to put up there.

Initially I was considering either a fan dipole or ZS6BKW. But then a few hams suggested a doublet fed with ladder line. And mentioned the site trueladderline.com where you can buy wire antennas with homebrew 600ohm feedline.

I don't think I can get the open wire feedline through my window since the frames have metal in them. I'm currently using a Comet CTC-50M, which is a flat 50 ohm coax jumper, to feed coax through my window.

It seems I can either feed the open wire directly into a remote antenna tuner that accepts balanced feedline, or terminate the open wire into a balun then run coax to a tuner indoors. It seems the coax losses would be terrible if I went with the latter.

Are there any remote automatic tuners that can be fed directly with open wire? So far the only ones I found are indoor tuners.

UPDATE: turns out my windows are vinyl. and i can fit open wire through them. can i just feed it straight to a balanced tuner (like an MFJ-993B) and be good to go?

  • 2
    $\begingroup$ Have you considered a "slightly off-center fed dipole"? $\endgroup$ – Brian K1LI Jun 30 '20 at 0:09
  • $\begingroup$ Which bands do you want to use? $\endgroup$ – Mike Waters Jun 30 '20 at 0:20
  • $\begingroup$ @MikeWaters i initially was fine with just 40m but I got a taste of 20, 10, and 17 and wanted more. $\endgroup$ – Paul Jun 30 '20 at 1:47
  • $\begingroup$ @BrianK1LI I’m using an OCFD right now (1:2 leg ratio so maybe not so slight). I had read on forums that OCFDs have unbalanced currents and lead to common mode issues. If that is easy to address then that’s another antenna I can consider. $\endgroup$ – Paul Jun 30 '20 at 1:52
  • $\begingroup$ @Paul The unbalance currents may not be so great with the "S-OCFD" because the intentional imbalance is smaller. (I did not measure.) Winding the feedline through an appropriate ferrite toroid near the connection to the balun chokes off the unbalance currents that might flow down the outside of the coax shield. $\endgroup$ – Brian K1LI Jun 30 '20 at 11:24

Any of these antennas would work. My advice: do what's easy or whatever leverages what you already own.

Are there any remote automatic tuners that can be fed directly with open wire? So far the only ones I found are indoor tuners.

It may exist somewhere, but it's probably not very common, because:

  1. coax feedlines are popular for their ease of routing, and all-weather performance, and
  2. a balanced tuner requires twice as many components.

You could however use a balun between the balanced transmission line and the unbalanced tuner.

But, why would you want to do this?

There's nothing "magic" about ladder line, except that it's much cheaper than coax of similar loss, and it's easy to make at home with a spool of wire and some suitable material for insulators. The idea is that the low loss will offset the high loss due to SWR and the end result will be acceptable loss.

But if you have a remote tuner you can just put the tuner right at the feedpoint. Now there isn't any section of feedline with high SWR, so there's substantially less benefit to go replacing your feedline with a lower loss feedline.

If you don't already have a remote tuner, but you do already have a coax feedline to a dipole, I'd say you're much better off with a fan dipole.

  • $\begingroup$ hey Phil- I just updated my question. the windows are vinyl and i'm able to close them completely over the open wires. $\endgroup$ – Paul Jun 30 '20 at 20:25

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