> If rain, ice and frost is a concern, then the BQH12J is be far the best choice.
> No other antenna has such a wide VSWR bandwidth. To illustrate what I mean
> see the attached .PCX file.
>
> The antenna has very good G/T and has extremely high stacking gain (3 dB)
> using the DL6WU stacking formula. It is also has a true 50 ohm Z.
>
> The only question is how do you wish to feed the antenna? Direct feed with
> coax or a folded dipole and a 4:1 balun? Direct feed with 50 ohm coax makes
> the feed very simple. Technically it is not balanced but as has been proven
> by many EME stations, it works very well (SM2CEW, F/G8MBI etc)
>
> The element lengths below are HALF length. Therefore, you must multiply the
> length by TWO and then add the Boom Correction one time only.
>
> Example: Reflector: 512.5450 x 2 = 1025.09MM + 4.16MM (28MM boom) = 1029.25MM
>
> Questions??
>
>
>
> VE7BQH 2.81 WAVELENGTH 4MM Elements :
> 143.800 144.100 145.200 MHz
> 12 elements, millimeters
>              4.0000    9.0000
>    0.0000  512.5450    0.0000
>  360.0000    0.0000  492.5008 Use the separate chart for the driven element.
>  525.0000  473.8803    0.0000
>  900.0000  471.0734    0.0000
> 1350.0000  461.2091    0.0000
> 1875.0000  457.9076    0.0000
> 2460.0000  455.5454    0.0000
> 3090.0000  451.2854    0.0000
> 3750.0000  449.3888    0.0000
> 4440.0000  448.9143    0.0000
> 5215.0000  447.0152    0.0000
> 5825.0000  444.6386    0.0000
>
> VE7BQH MODIFIED DJ9BV YAGI.                        .
>
> E PLANE = 32.8 DEG.                                .
> H PLANE = 35.8 DEG.                                .
>
> DL6WU STACKING:                                    .
>
> E PLANE = 3.66M                                    .
> H PLANE = 3.40M                                    .
>
> XPOL Stacking = 3.53M in both planes               .
>
> Split Dipole = 470MM + 470MM
>
>
>                     .
>
> 1. BOOM CORRECTION FOR THROUGH THE BOOM INSULATED ELEMENTS ON 2 METERS.
>
>    PROVEN ACCURATE FOR BOOM DIAMETERS SMALLER THAN .055 WAVELENGTHS.
>    MEASUREMENTS BY DL6WU.FORMULA BY G3SEK.
>
>    FORMULA: C = 12.5975B - 114.5B^2
>             C = CORRECTION FACTOR AS A FRACTION OF THE BOOM DIA.
>             B = BOOM DIA IN WAVELENGTHS
>             B^2 MEANS B SQUARED
>
>    2 METERS
>    BOOM DIAMETER           CORRECTION               ADD
>    2 METERS.
>    0.750" OR 19.050MM        10.56%          .0792" OR  2.02MM
>    0.875" OR 22.225MM        12.14%          .1062" OR  2.70MM
>    1.000" OR 25.400MM        13.66%          .1366" OR  3.47MM
>    1.125  OR 28.575MM        15.13%          .1702" OR  4.32MM
>    1.250" OR 31.750MM        16.54%          .2068" OR  5.25MM
>    1.375" OR 34.925MM        17.90%          .2462  OR  6.25MM
>    1.500" OR 38.100MM        19.21%          .2882" OR  7.32MM
>    1.750" OR 44.450MM        21.67%          .3792  OR  9.63MM
>    2.000" OR 50.800MM        23.91%          .4783" OR 12.15MM
>              20.000MM        11.04%                     2.21MM
>              28.000MM        14.87%                     4.16MM
>              30.000MM        15.78%                     4.73MM
>              32.000MM        16.66%                     5.33MM
>              38.000MM        19.17%                     7.29MM
>
>
>