Don’s Antenna talks by N4DJ

Dipoles are great antennas and not just for beginners! I gave up my towers and Yagis over 30 years ago and went to all dipoles. I really have not missed anything. With dipoles I can work over 100 countries in a weekend DX contest and on more than one band, including 40 meters. My 20 and 10 meter dipoles are just over 32 feet with my 40 meter dipole close to 50 ft. I use it on 15 meters also. They work pretty good. For DX it is good to have them high. How high? As high and you can get them. Most of us should be able get them 30 feet and that works for 20 meters and up really well. Higher is a bit better. Mine are all between 30 and 50 feet. Theoretically the 40 meter dipole works better at 60 feet but even 30 feet works. Dipoles have a broad bidirectional beamwidth off the broadside with a null directly off the tip end. Low dipoles do not have a deep null but a 10 meter dipole at 32 feet will because it is a wavelength high, whereas the null of a 20 meter dipole at 32 feet is much less ...

 I have had half square antennas on 80, 40 and 20 meters. In all cases the top wire (spacing) was one-half  wave length long on the band I built it for. The half square is not a multiband antenna. My results were that the 80 meter antenna was the best antenna I ever had ( except maybe my full size 4 element 20 meter monobander)! The top wire was at about 60 feet or so. On 40 meters the Half Square antenna worked but not nearly as well as my 40 meter dipole in that it seemed to have the same gain in Europe but a more narrow pattern resulting in deeper nulls of the side than the dipole which was at about 35 feet. On 20 meters any full size (halfwave) dipole or end fed is hands down at least an S unit better if it is a halfwave (32 feet) or more high! I model a lot with EZNEC and the EZNEC results were almost exactly what I saw in practice. Any dipole or halfwave wire will have a gain of about 8 dBi if anywhere near a halfwave high. Any vertical over real earth will have maybe 0 ...