Hello and welcome back to my blog. Since we briefly touched on antennas in our last post, I thought this would be the next logical topic. In this post, we are going to do a general overview on different types of antennas. In later posts we will go into a more in depth view of them as well as the theory behind them and even plans on how to build them. This topic I think will be spread out of the next few posts so please stay tuned to further posts on this topic. Now, lets move onto the meat of this post, ok?
So first off, lets talk about the two general types of antennas. The two basic types of antennas are omnidirectional and directional.
Omnidirectional antennas transmit and receive in a way that the name sounds. They transmit and receive in all directions at once. This has its advantages and disadvantages. The advantages of it is that if you are talking to someone to the north of you and someone calls you that is located south of you you can hear them call you. This disadvantage of it is that the power that is being transmitted from your radio is that it is radiated in all directions. So when you are talking to that person to the north of you, the power that is being radiated to the west, south and east is being wasted.
Omnidirectional antennas are probably the most commonly used antennas in the communications industry. For the ham radio operator, they are the antenna that you have on your vehicle or the vertical antenna that you have at your house. For non-hams, your stereo in your vehicle uses one, tv and radio stations use them, the antenna on your wifi router also uses one. Omnidirectional antennas are perfect when you need broad coverage or you dont know which direction the signal will be coming from.
With directional antennas, they are built in a way that the power that is radiated towards the back of the antenna is cancelled out and the power that is transmitted towards the front of the antenna is reinforced. The result of it is a radiated beam of energy that is transmitted in the direction the antenna is pointed, much like a flashlight does with light.
Directional antennas are used for many things, not just ham radio. If you have an outside tv antenna, that is a directional antenna. Yea I know, these types of antennas are getting fewer and far between, because a lot of people have satellite TV now-a-days, Well, the satellite dishes are also directional antennas known as parabolic dishes.
Like I said above, this is going to be the first post in a series of posts talking about antennas. The next post will be covering omnidirectional antennas. We will talk about the different types of antennas for both vhf/uhf and hf bands. We will talk about how to make your own antennas and the formulas behind building your own antenna.
Followed by directional antennas. Directional antennas are a little more complicated that omnidirectional and take more pieces to build one. We will also go into the process of building one and all the math behind it.
The last of this series will be covering safety. Well will talk about safety regarding antenna construction, installation and RF safety. Remember with anything that you do, not only those things that have to do with ham radio, safety first. As a 911 dispatcher and a ham I have heard my share of accident stories when it comes to things that happen when the person doesn’t the proper precautions.
I think we will end this post here. I hope that I gave you some food for thought about antennas and peaked your interest about this topic. As usual, please share my blog with your friends or those that might be interested in ham radio. Don’t forget to like my facebook page or click on the subscribe button on the right to be alerted of new posts.
73 de K5CLM