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## Re: [TowerTalk] Half-Square formula?

 To: , "TowerTalk" Re: [TowerTalk] Half-Square formula? "Jim Lux" Sun, 7 Nov 2004 16:55:47 -0800
 ```What you are probably seeing is the various "corrections" for end effects and loading. The "resonant length" for a dipole (where resonant is defined as having zero reactive impedance component at the feedpoint ) depends to some degree on the surroundings (i.e. the ground properties for a monopole over a conductive ground) and the length/diameter ratio of the antenna (a/l in the antenna literature). It also depends on whose analysis you want to start with King, Hallen, or Schelkunoff (sp?), since they all come up with slightly different numbers for approximating the feedpoint impedance of a particular configuration. Even in a method of moments model, there's the whole issue of how you treat the end of the conductor. Is it a flat cap? Is it a rounded hemisphere? etc. ----- Original Message ----- From: "Paul B. Peters, VE7AVV" To: "TowerTalk" Sent: Sunday, November 07, 2004 4:41 PM Subject: [TowerTalk] Half-Square formula? Over the past couple of weeks I have been researching the half-square antenna. While a combination of magazine articles and Internet-based information produces a significant amount of data and experiences with this antenna, the one thing that varies is the formula used for both the horizontal and vertical elements. For example, on LB Cebik's site http://www.cebik.com/scv4.html he suggests, "the relatively invariant relationship between the horizontal and vertical dimensions of the half square for a maximum-gain configuration tends to assure a good utility for the formulas". Where H is the horizontal length in feet, V is the vertical height in feet, and f is the frequency in MHz, he suggests the use of V=278/f MHz and H=447/f MHz. In other articles, the number for both H and V elements is either 468, 492 or 1005 and the half or quarter wave product of these calculations. Suffice to say, the base numbers produce some significant swings in the two values. While I tend to lean towards the LB Cebik material -- simply given the mass of research he has undertaken over the years, I am curious what the members of this group can offer in terms of opinions on the formula. My thanks in advance for any and all replies. 73 de Paul, VE7AVV StoneyGround Station -|<*><*>||<*><*>||<*><*>||<*><*>||<*><*>||<*><*>||<*><*>||<*><*>|- "All email from this address is checked by Norton AntiVirus 2003" _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA. _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA. _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
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