This e-mail contains the YO file for the full size 3 element 40M Yagis on 48 foot booms at W3LPL, one at 190 feet and the other at 100 feet. These antennas have been in use for 25 years with excellent success. The design is a compromise between gain, front/back ratio and VSWR across the entire band. A three element Yagi does not have enough variables to allow a good compromise design covering the entire 40M band; therefore, the design favors good f/b ratio and VSWR from 7000-7100 kHz, good gain from 7000-7300 kHz and acceptable VSWR from 7150-7300 kHz. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - W3LPL 3 Element 40 Meter Yagi (as Built) Height 2280.000 7.000 7.100 7.300 7.100 MHz 3 elements, inches 2.0000 1.8750 1.7500 1.6250 1.5000 1.3750 1.2500 1.1250 1.0000 0.0000 72.0000 121.5000 16.5000 16.5000 17.0000 17.5000 18.0000 18.0000 134.0000 258.0000 72.0000 121.5000 16.5000 16.5000 17.0000 17.5000 18.0000 18.0000 110.0000 564.0000 72.0000 96.0000 15.0000 15.5000 16.0000 16.0000 16.5000 17.0000 125.0000 Use the H key to set the elevation angle to 10 degrees. Use the M and Tab keys to enter the following T-match parameters: Rod Diameter 0.5" Rod Spacing 10" Rod Length 144" Lead Length 6" Series Cap 99999 pf Feed Z 200 ohms Experience indicates that the driven must be lengthened to 125 inches, the length that produces a modelled impedance of +j20 at 7.1 MHz - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -