HOW TO READ ANTENNA ARTICLES

There are lots of antenna articles out there. How do you make sense of them?

First, understand that there are 3 major components to any antenna: the electrical design, the mechanical construction, and the feed method.

The electrical design determines the behavior of the antenna – the radiation pattern, gain, etc. For a given application, I may choose to use a simple dipole, put a reflector behind it to create a 2-element yagi, make it longer to get more gain, or use some form of loop or long wire antenna instead.

The mechanical construction relates to the actual element and supporting materials, and how they are assembled. This affects the weight and strength of the antenna. A dipole might be made from heavy aluminum tubing to go on a tower, or light wire for backpacking.

The feed method relates to how the RF gets from the transmitter to the antenna (and vice versa). It includes any needed impedance matching. So my dipole might be fed directly with coax, or use a balun, or be in the form of a folded dipole with two parallel wires, or use a beta or delta match with open wire feedline, but it still acts like a dipole.

Very often the author of an antenna article is really describing ONE of these components – the other parts of the antenna are pretty standard.

For example, maybe I’m describing using a delta match to feed a portable yagi, as it allows me to attach the feedline to the driven element with alligator clips, and the driven element is continuous through the boom for strength. So may be an interesting alternative feed method that can be applied to other types of antenna (such as dipoles or quads), while the electrical design of the yagi in the article could be fed with some other method, and the mechanical construction could be different.

So the first question is, what is different about this particular antenna that justifies writing an article about it? In this case, it was the feed method, the use of the delta match with a yagi antenna. Maybe you don’t really care about the delta match, but you like the way I connected the yagi elements to the boom, or how the elements could be removed and slipped inside the boom for storage / transport. Great! You can use that mechanical construction for your designs, even if you don’t use the delta match with it.

If you read antenna articles this way, as a collection of basic building blocks, then you can use those blocks in different combinations for your own antennas.