For Switching 2 Coaxial Lines Simultaneously!

Freq. 0 to 500 me; Power Rating to 1 kw;

Standard coil voltage and other r.f.

Connectors available.

0K2-4Owith uHF Conne^Tors, e«* S19 Connectors available.

Manufactured jnd Guaranteed by DOW-KEY CO., thief River Falls, Minn.

two of the elements of the four element quad as si town in Fig. 5, it becomes possible to have a two element 40 meter parasitic beam with one-half wave elements folded in the shape of a square. These stubs had absolutely no affect on the 20 meter quad operation.

At this writing no further adjustments have yet been made to improve the operation of the 10 meter elements which do exhibit some directivity but with little front to back ratio.

Time has not permitted further experiments along this line but one wishing to have a four element 20 meter quad and a 40 meter beam antenna with the same transmission line and no relays or switches, this mav be worth further investigation. Fig, 5 shows how the stnbs are attached- It must be noted, however, that the word beam*' was used as it has been "sweatfully" learned that a so-called shortened quad with loading coils or stubs will take a load and show some directional properties, but with anything less than one quarter wave spacing between upper and lower and/or side to side wires the arrangement looses the quad characteristics.

Some readers may have noticed the unbalanced method of feeding the quad directly with the coaxial cable. Various horizontal pattern measurements have been made and in each, only the small rear lobe is partially distorted with no effect on tiie forward lobe. This was a very minor consequence from this point of view. Of course, a balun or gamma match could be used to rectify this situation and again one may refer to most any handbook.

Reversing the coax leads will, of coxirse, reverse the slight distortion of the pattern on the rear lobe.

The final outcome of these quad experiments has been very gratifying. The signal from here lias been greatly improved from short paths it is gratefully acknowledged ol Reeve K4AW, Walt the late K5JLO in New Orleans, Jim VK6SA and Lambert ZS6IF. Locally to Annan K4FOM, Frank K4YPA. John K4UGE and others who graciously gave of time and energy. . . . W4AZK


over the past few years and those with an experimental nature will find numerous new features in the antenna field within which to explore.

Experiments are now under way on a full sized dual band four element quad for 40; 20 and 15 meters. Gain figure for 15 meters should exceed 15 db and 8 db on 40 meters. For invaluable help on tests over long and

Was this article helpful?

0 0

Post a comment