john@anasaz.UUCP (John Moore) (01/14/90)
I am interested in finding the following information, either in tables of formulas or, even better, as computer programs. I am on usenet, and not the internet, so cannot access internet archives using ftp. What I would like to see filled in is the following table: Antenna Type Effective Input Radiation Aperture Impedance Resistance Short Dipole ???? ??? ??? Long Dipole ???? ??? ??? Short g-plane qwave ???? ??? ??? Long g-plane qwave ???? ??? ??? Magnetic Dipole ???? ??? ??? -- John Moore (NJ7E) mcdphx!anasaz!john asuvax!anasaz!john (602) 951-9326 (day or eve) long palladium, short petroleum 7525 Clearwater Pkwy, Scottsdale, AZ 85253 Freedom and Communism are incompatable.
koning@koning.dec.com (Paul Koning) (01/16/90)
In article <1172@anasaz.UUCP>, john@anasaz.UUCP (John Moore) writes: > I am interested in finding the following information, either in > tables of formulas or, even better, as computer programs. I am > on usenet, and not the internet, so cannot access internet > archives using ftp. What I would like to see filled in is the > following table: You might look at J. Kraus, Antennas, second edition. That book is considered by many to be the ultimate reference in this area. I was going to quote some answers from the book but find that I can't since the antenna type designations are ambiguous. Does "long dipole" means 1/2 wave, or longer? What is the difference between input impedance and radiation resistance -- the reactance, the losses, or what? Anyway, here's an attempt... Antenna Type Effective Input Radiation Aperture Impedance Resistance Short Dipole 0.119 2 Ohm for .1 wave Long Dipole (1/2 wave) 0.13 73 Ohm >Short g-plane qwave ???? ??? ??? >Long g-plane qwave ???? ??? ??? >Magnetic Dipole ???? ??? ??? ^ is that a loop? What size? paul, ni1d
pierson@cimnet.dec.com (01/16/90)
In article <1172@anasaz.UUCP>, john@anasaz.UUCP (John Moore) writes... >I am interested in finding the following information, either in >tables of formulas or, even better, as computer programs. I am >on usenet, and not the internet, so cannot access internet >archives using ftp. What I would like to see filled in is the >following table: > >Antenna Type Effective Input Radiation > Aperture Impedance Resistance > >Short Dipole ???? ??? ??? >Long Dipole ???? ??? ??? >Short g-plane qwave ???? ??? ??? Is the "qwave" the length of the driven element or the g plane? >Long g-plane qwave ???? ??? ??? same query. My understanding is that making ground plane elements longer than 1/4wave (radius) has no effect (after the voltage peak at 1/4wave, the rest of the wire is "invisible...) >Magnetic Dipole ???? ??? ??? All this, and more, is available in any good antenna engineering text or reference (Antenna Engineering Handbook, Jasik, comes to mind. Graphical representations are in the ARRL handbook, I forget how many of the formulae (formulas?) they include.) Numerical values for "short" and "long" will be needed. Off hand, both the impedance and radiation resistance will get arbitrarily low for "short" (measured in wavelengths) antennas, rise to a maximum for half wave, then fall again, then rise, then... Feed point also needs to be picked (end feed a half wave, high z, center feed, 75ohm). (Which is just a different way of stating the last sentence in the prvious para...) Hopefully, somebody else can supply some program names or sources. thanks dave pierson |The facts, as accurately as i can manage, Digital Equipment Corporation |The opinions, my own. 600 Nickerson Rd Marlboro, Mass 01752 pierson@cimnet.enet.dec.com