Free! Excel Worksheet for Building Any 1/2 Wave Dipole (Center-Fed, OCF, Windom, New Carolina Windom)

Here is a spreadsheet I designed in Microsoft Excel for calculating the first cut and the final cut (after testing) of a 1/2 wave dipole, whether center-fed, classic off-center-fed, Windom, or New Carolina Windom. If you use it for a plain ol’ center-fed dipole, just ignore the references to “long leg” and “short leg” — the numbers will still be right. Anyhow, you’re welcome to use it, pass it around, whatever:

DipoleWorksheet.xls (Microsoft Excel)

I’d enjoy hearing from any of you who end up using this spreadsheet to build an antenna!

If you find any bugs in this spreadsheet, please let me know. Note that it is protected for your convenience, but you can unprotect it anytime you like to see the formulas in each cell (there is no password).

Todd Mitchell, NØIP, is a regular contributor to and writes from Minnesota, USA. He can be contacted at [email protected].

8 Responses to “Free! Excel Worksheet for Building Any 1/2 Wave Dipole (Center-Fed, OCF, Windom, New Carolina Windom)”

  • Tom Kb3hg:

    What do I need to open this file? my excel gets nothing but a sheet filed with code. XLSX? file

    Tom [email protected]

  • Todd Mitchell, NØIP:

    Dear Tom,

    I used Microsoft Excel 2007 to prepare this spreadsheet. Here’s another link to a version that might work for you. I just tried saving it in Excel97 format, thought it warned me some formatting features might not work:

    It should look like this:

    Please let me know how this works for you.



  • K4TOJ - Tom:

    The XLSX file is Excel 2007 and higher.

  • Bill Taylor KC5DPJ:

    I used LibreOffice Calac to open this file and it works great. Thank you very much for the worksheet. Will it work ok on a fan dipole by just changing the appropriate numbers?

  • Todd Mitchell, NØIP:

    Dear Bill,

    You’re welcome!

    Depending on what you mean by “fan dipole” it may still work. Often what people mean by “fan dipole” is really just an array of 1/2 wavelength center-fed dipoles cut for different frequencies, all fed in parallel. If this is what you mean, then the spreadsheet should work well for you to cut each of the 1/2 wavelength dipoles you want to put in your array.

    But the true “fan dipole” is a different animal. Check out the “Broad-Banded Coax-Fed Fan Dipole” described and depicted here: According to that write-up, “A broad-banded dipole for 75/80 meters can be constructed by attaching two equal length dipoles to the center feed-point and spreading the ends about 3 feet apart using PVC water pipe to separate them. The completed dipole looks like a bow tie. This makes the antenna to appear electrically to have that of a large diameter conductor. Because of this, the overall length will need to be shorter than a single wire alone. When we used the antenna, we found a length of 110 feet would cover most of the 75/80-meter band without a tuner.” 110 feet is shorter than 1/2 wavelength even at 4.0 MHz (117 feet) and significantly shorter than 1/2 wavelength at 3.5 MHz (134 feet). I wouldn’t use this spreadsheet for that kind of antenna.



  • Tom Kb3hg:

    Thanks, The new file works thanks.
    And yes I’m still using the 97 version.
    Thank you again,

    Tom Kb3hg

  • Todd Mitchell, NØIP:

    You’re welcome, Tom. Let me know how it works for you if you use it to construct an antenna!

  • Craig W6CAW:

    Great idea. Will have to try the spreadsheet as I finish tuning my 160/80 meter Carolina Windom fan dipole. Yes, I built one this summer.

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