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Tune Around! Topics For
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The 40 Meter Southcars 3 Element Quagi Beam ! By NA4L Dave
The quagi antenna is a little bit of quad and a little bit of yagi design. The quagi was orginally designed by k6ynb/n6nb in 1972. It is usually used on V.H.F., but I decided to give it a "whorl" on 40 meters. You will need lots
of room for this antenna!
In my design there is no boom, just oak trees holding the elements up about 62 feet at the center insulators.
(I constructed the loops as diamond shapes because the director is not perfectly horzional).
The quagi is made to resonate on 7.251 mhz, the Southcars net frequency.
Since about 90 % of my checkins when I am net control are south of my qth, I have the antenna pointed about 200 degrees or S.S.W.
How does it play? I have the f/b ratio at about 18db. The forward gain is about 8db over my reference dipole in the favored direction. These figures are a conserative number.
The quagi "hears" well !
Being mostly a closed loop antenna system helps to reduce the noise figure and raise the antenna aperture.
In case
you have difficulty reading the element lengths and spacing here they
are: Spacing Reflector to driven = 27 feet Driven to director = 30 feet
Note....The feedpoint matching is simple because adding the extra elements drops the driven loop to about 50 ohms which is a perfect match using a 1 to 1 balun and rg-8x coax. Why don't you give the quagi a "whorl"....if you have the room!. 73 Dave NA4L
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