Which is the only replaceman open-wire feeder at 600 ohms. They don’t make it any longer, you’re on your own to construct it or make-do with ladder line.

Yes you can definitely build your own ladder line. The insulators are available. But it's probably easier to use window line [0] instead.

[0] https://www.trueladderline.com/blog/window-line-open-wire-fe...