be variable as with any beam antenna, depending upon the conditions at that time, Safely, the four element quad has 23 to 35 db front to back ratio. The forward gain showed 12 to 14 db over a dipole erected at the same height for test purposes. Of course, under some conditions of back scatter these figures ;irc somewhat lower. The greatest gain is apparently on some lower vertical angle. Our tests methods did not include vertical angle measurements. However, a 2 S unit gain over a dipole is not to be sneezed at.
It is true that many yagi type beams show 10 db or more gain, but when it comes to getting a db or more, the average ham disregards this. "Well, it won t show up on the S meter." True, but has it ever been noticed that the "big signals" get to the Dx'er (who rn:iy not even have an S meter other than his own two ears) by a margin of only one-half of an S unit or less over the gang in a pile up? (3 db gain is enough for a noticeable change to the ear). How this apparent additional gain is achieved is not fully understood.
A further experiment with the four element quad was to operate two of the elements on 40 meters. The method used was stub switching.
The characteristics exhibited by transmission line segments as can be obtained from most any handbook, show that a half wave section of transmission line at a given frequency shorted at one end will exhibit the same impedance at the opposite end, That is zero or shorted regardless of the characteristic impedance of the transmission line. This property, coupled with the fact that a similar line one quarter wave length at a given frequency shorted at one end offers an infinite impedance at the opposite or shorted end. hus, the same stub at 14,200 kc will oiler a short opposite the shorted end, but at 7,100 kc will exhibit an infinite impedance or insulator opposite the shorted end. When this principle applied to
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