- October 19, 2016 at 8:42 am #6002
http://www.qsl.net/kk4obi/index.html Is a very good site for wire antennas. Nearly every shape and height AGL has been analyzed with graphs and plots plus a discussion. Flat top, inverted up and down Vs, sagging, Ls, and more are covered. The NEC2 models are included for each.
My take away is it is hard to beat a flat top at 1/2 wave high if you going to use a wire antenna.
Amherst, NHOctober 19, 2016 at 9:58 am #6003
Absolutely!!! There’s a reason the 1/2 wave dipole is the basic building
block of most antenna constructs. Compared fairly, the dipole will beat
or match any single element antenna. Not just my opinion. Visit Tom Rauch’s website, www.w8ji.com.October 21, 2016 at 8:40 pm #6040
With the availability of antenna modeling software these days, it is fairly easy to model just about any kind of antenna configuration you dream up. This is good news for those in space-challenged QTHs. L.B. Cebik, W4RNL (SK), was a prolific modeler who wrote extensively about his efforts. His works are available through Antennex. (Google it for more details.)
One issue I have with all modeling programs is that, like the Internet, people tend to take the results as absolute. To really understand the fundamentals behind antennas requires a strong background in electromagnetic theory, aka the fusion of calculus and physics. If you are curious to understand what is “under the hood”, I recommend searching for a copy of “Antennas”, published in 1960 by John Kraus, W8JK (SK). Dr. Kraus was an EE professor at Ohio State who developed many unique antennas. (A former colleague of mine reported suffering through his class as a PHD candidate.)
73 de TEOctober 22, 2016 at 10:06 am #6042
One of the houses I lived in had a flat roof. Using Dr. Krause’s Book, I built a simple W8JK 2-element Flat-Top. I nailed a 4-foot length of 2×4 support plank on each corner of the house and used wire feedline through a Harvey-Wells matchbox to load it on all bands. I worked all over the world with that setup!
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