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CUBICAL QUAD ANTENNA CALCULATOR

Enter center frequency to be calculated for a quad :  If you want to use it between 144mHz and 146mHz enter 145 in the mHz box.
mHz
  Total Length ONE SIDE Spreader Arm Length
ONE SIDE  "C"
Reflector inches

centimeters

inches

centimeters

inches

centimeters

Driven Element  inches

centimeters

inches

centimeters

inches

centimeters

Director 1  optional inches

centimeters

inches

centimeters

inches

centimeters

Director 2  optional inches

centimeters

inches

centimeters

inches

centimeters

Director 3  optional inches

centimeters

inches

centimeters

inches

centimeters

Director 4  optional  inches

centimeters

inches

centimeters

inches

centimeters

Director 5  optional  inches

centimeters

inches

centimeters

inches

centimeters

 

C= Spreader arm Length

Reflector tuning stub 

spacing between the reflector and driven element should be 
inches 

centimeters

.

spacing between the driven element and the first director and between the directors should be

inches 

centimeters 

Gain vs Spacing

The gain of an an antenna with parasitic elements varies with the spacing and tuning of the elements, and thus for any given spacing there is a tuning condition that will give maximum gain this spacing. The maximum front to back ratio seldom, if ever occurs at the same condition that gives maximum forward gain. The impedance of the driven element also varies with the tuning and spacing, and thus the antenna system must be tuned to its final condition before the match between the coax and the antenna can be completed. However, the tuning and matching may interlock to some extent, and it is usually necessary to run through the adjustments several times to insure that the best possible tunning has been obtained. (ARRL Radio handbook)
 

 
  Order How to Build and Adjust Quads
  or
  The Quad Antenna: A Comprehensive Guide to the Construction, Design, and Performance of Quad Antennas


LINKS:

Order Practical Antenna Handbook with CD ROM
By Joseph J. Carr. The world's favorite antenna book. The most popular book on antennas ever written, widely known as "the antenna builder's bible," Joseph J. Carr's Practical Antenna Handbook, Third Edition is a work for anyone, ham radio operators, shortwave radio listener's -- anyone with an interest in antennas, from the newest of novices to the most experienced engineer. This empowering book gives you all kinds of projects, yes. And it gives you material that explains why what you did works. But most importantly, it prepares you to design and construct your own antennas "for the cases," Carr modestly suggests, "That the author thoughtlessly failed to cover." This third edition blends, in Joseph J. Carr's words, "the theoretical concepts that the engineers and others need to design practical antennas, and the hard-learned practical lessons derived from actually building and using antennas--real antennas made of real metal--not merely theoretical constructs on a blackboard." Add it to your working library, and pretty soon it'll assume a favorite spot inside your toolbox, beaten up, tattered, annotated with your personal notes...obviously used to the fullest extent. Introduction to Radio Broadcasting and Communications. Radio Wave Propagation. Transmission Lines. The Smith Chart. Fundamentals of Radio Antennas. High-Frequency Dipole and Other Doublet Antennas. Vertically Polarized HF Antennas. Multiband and Tunable-Wire Antennas. Longwire Directional Antennas. Hidden and Limited Space Antennas. Directional Phased Vertical Antennas. Directional Beam Antennas. Antennas for Shortwave Reception. Large Wire Loop Antennas. Small Transmitting and Receiving Loops. Wire Antenna Construction. Antenna Modeling Software. VHF/UHF Transmitting and Receiving Antennas. Microwave Waveguides and Antennas. Antenna Noise Temperature. Antennas for Radio Astronomy. Adjusting, Installing, and Troubleshooting Antennas and Transmission Lines. Antennas for Radio Direction Finding (RDF). Impedence Matching in Antenna Systems. Mobile, Emergency, Portable, and Marine Antennas. Antennas for Low-Frequency Operation. Measurement and Adjustment Techniques. General Antenna Mechanical Construction Techniques. Grounding the Antenna: What Is A Good Ground?
  
 
Order Antenna Theory and Design:
A book on principles and development techniques for examining and designing antenna systems. Emphasis is on basic topics and applications, and much material does not rely heavily on mathematics.  
 
12/30/01

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copyright 2000, 2001 & 2002 by Frank Cross.
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