Open Wire Feeder Calculator

[aa5wg]

Here is a nice link for calculating open wire feeders.     http://www.smrcc.org.uk/tools/OpenWire.htm
I made the mistake and plugged in diameter instead
RADIUS a couple of times.  

Chuck

Update:  Here is a link to a wire gauge size chart that will complement the above open wire feeder link:  http://www.powerstream.com/Wire_Size.htm

[W0BTU]

Looks good.

I have a spreadsheet at http://www.w0btu.com/files/antenna/OpenWireZ.xls. It's for open-wire line parallel to the ground, for Beverage antenna calculations. It also takes into account the dielectric constant, so it's also good for ladder line and twisted-pair line.

More calculators at http://www.w0btu.com/Beverage_antennas.html#How_far_apart (page down).

[aa5wg]

Mike:
You did a lot of work to build your Web Site.
There is much good information to read.

Chuck

[W3GMS]

Very nice site Mike.  A lot of very good practical information.  Thanks for sharing the information.
73,
Joe, W3GMS

[k4kyv]

Nice info, Mike.  I'm amazed at how much technical knowledge is out there just within the amateur community. Thanks to the internet, that knowledge is at everyone's fingertips - literally. And not to mention the free and for-pay commercial sites. In the old days I was limited to whatever books and magazine articles I happened to have in my library, and much of the information I would need at a given moment always seemed to be non-existent.  Over the years I have accumulated loads of books, complete runs of QST from the 1920s, solid decades of IRE Proceedings, Radio magazine and R/9, CQ, Ham Radio and others.  With all that information in the library covering almost any topic imaginable, finding a specific item can be like looking for a needle in a haystack (or perhaps a SMT resistor in my junkbox or shack), often more trouble than it's worth.  I find my paper library collecting more and more dust, but still, I wouldn't part with any of it. Too bad it couldn't have a search feature.

One item that particularly caught my eye was the photo and text explanation "How to tension the two wires equally". I wish I had thought of that when I constructed the 140' run of OWL made of #8 copperweld last spring.  I did mine the hard way: suspended both conductors between a tree trunk and the riding lawnmower (as a second fixed anchor), attached one end of each wire to one of the anchors via a set of turnbuckles, adjusted the turnbuckles for precisely equal sag in both lines, marked several reference points along the line using a combination square and one of those silver Sharpie permanent markers auto mechanics often use to make marks on engine blocks, took the lines down, cut them at the end-point marks, strung them on the poles, and adjusted the turnbuckles on the pole until the reference marks lined up.

I don't like permanently leaving pulleys in my antenna installations, but it would have been much simpler to have equalised the tension in the lines using the three-pulley method, then marked the lines and proceeded as explained above.  It took me several hours to initially get the adjustments just right for equal tension using the two turnbuckles, checking, double-checking and then triple-checking before making the reference marks.  

And Mike, glad the Joplin tornado didn't pass through your place.

[W0BTU]

Thank you for all the kind words, Gentlemen! However, much of the info on w0btu.com came from others a lot smarter than me, and I really can't take credit for it all.

Don, those tensioning pulleys have solid bronze pulleys and plated steel frames and pins. That's all I use for antenna supports here, and they are not expensive at all. They were just what the local hardware store had, but I think they are perfect for our application. I don't think that they will either wear out or seize up for a very long time.