The following dimmensions will be found useful in constructing effective
Groundplane antenna's.

Feed the antenna with 50 ohm RG68 coax for best results, and try to get
the feedpoint at least 1/4 wave above ground.

The number of radials is not critical,but I have found 3 to work best
spaced 120 degrees apart.

The basic formula for constructing the antenna is

                          (468/Freq (Mhz))/2

                     This gives the answer in Feet

       Multiply the decimal part by 12 to give the inches.

       The radials are 5% longer and MUST be exactly the same.

BAND               RADIATOR           RADIAL

40 m (7.05Mhz)     33Ft 2in           34Ft 10in

30m  (10.1Mhz)     23Ft 2in           24Ft 3in

20m  (14.05Mhz)    16Ft 7in           17Ft 5in

15m  (21.05Mhz)    11Ft 1in           11Ft 8in

10m  (28.05Mhz)    8Ft 4in            8Ft 9in

                              | Radiator
                              O  Feedpoint (centre of coax)
                             x x
                            x   x
                           x     x
                          x       x
                         x         x
                        x           x
                       x             x Radials (Min of 3)

 I have used this simple antenna for over 30 years and have always had
excellent results with it on QRP, Worked many VK and ZL on 14,21 Mhz
The radiator is best made out of 1/2in ali tube and the radials made from
14swg wire. dont forget to insulate the radial ends.

I would be interested in comments from anyone who uses this antenna and
the results you have had with it.

 73 es 72 to all fellow QRP operators

                       de John G3PTO  
                         G QRP 595

Thanks to John G3PTO for the above article.

Frank, G3YCC

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