Today we will discuss about the inverted V antenna, which is often the first antenna which a radio amateur builds himself. It is quite simple to build. I had also built one long long back, when I started coming on air, using my homebrew equipment. See how it is built. The inverted V dipole antenna needs only a single mast, that is the advantage. When a horizontal dipole antenna, we will require two masts. This requires only a single mast. Here we have mentioned that non conducting mast has to be used. If you are using a conducting mast, then the mast should be grounded well.
Then you need two other small supports. These will be fairly away from the ground and insulators are needed. There are insulators here on the mast and this is the connection of the coaxial cable, one to either side of the antenna limbs. These two are copper wires, made of copper wire, good guage copper wire. It can be insulated copper wire, or non-insulated, no problem and it could be single stranded, or double stranded or multiple stranded copper wire, no problem about that. And the what you have to use is the coaxial cable, if you are using a coaxial cable, you will need a balun over here, because, antenna, the inverted V dipole antenna is a balanced antenna, so coax is an unbalanced line, so we have to put a balun over here, before connecting the antenna. Then, the insulators, you have already mentioned. The inverted V antenna has an advantage that it has a low angle of radiation. Low angle of radiation means it will go to the ionosphere very well, and when it goes to the ionosphere very well, it can be reflected down to the earth, to a longer distance. So inverted V antenna is supposed to be better for long distance propagation.That is another reason why amateurs go for that, those who cannot build a large beam antenna. And when you have a low angle of radiation, and better DX work, this is one of the best suited. Then regarding the directivity, usually the horizontal dipole, if it is a horizontal dipole like this, the beam will go in both directions, towards the one side and opposite side also. Towards the end of the antenna, there will be hardly any radiation. In case of inverted V, since it is angulated, it is not as directive as the horizontal dipole, there is some radiation in other directions, because this is at an angulation. So it is partly an omnidirectional antenna, though it is not fully omnidirectional like a vertical dipole, this has some omnidirectional property, that also helps in working DX in different directions. If it is a horizontal dipole, it can go in these two directions only, towards the end, there will be no radiation, but inverted V dipole, there will be some radiation all around. So it is useful for a radio amateur who does not have a facility for a beam antenna with an antenna rotator. You know, beam antennas are costly, difficult to build, rotators are very very costly. So all those things are not there for a beginner. So when a beginner uses a inverted V, these are the advantages. But some care is needed, for example, these two are very near the ground. Suppose somebody is going to touch this antenna, it could give a RF burn, especially when the power is high. So you would like to have some protection here. That is at least, suppose you are installing this mast in the garden, and this end is your compound itself, you should see to it that nobody will go and touch these ends. These are the some precautions which you will have to take for protection of your own people and yourself, when you are using an inverted V antenna. In case of horizontal antenna, this is not required, because, both ends are quite high and nobody is going to touch it. So this is the difference between inverted V antenna and a dipole antenna. Thank you very much.
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24 авг 2024