The N7WS.MCD worksheet file supplied on the CD-ROM accompanying The ARRL Antenna Compendium, Vol 6 works only with the latest version, Version 8, of Mathcad. Download N7WS-V6.MCD below for a worksheet compatible with Version 6 of Mathcad. Sorry, because of the many new features that Mathsoft added to Version 6 and 8, Mathcad versions earlier than Version 6 are incompatible with this worksheet.
Download N7WS-V6.MCD, the Mathcad 6.0 compatible file.