Antenna

Continuing with our research into the CB craze of the mid 70s we’ll take a look at what were considered the elite antennas when it came to having a CB setup. While the truckers may have ruled the roads and channel 19, it was the everyday hobbyist who ruled the airwaves from his home, and rule they did.

If you were on CB and really wanted to impress people with your booming voice over the airwaves you had no choice but to set up a base unit. Not only were the units themselves powerful but the antennas that people put up on their roof tops could have given some rival TV stations a run for their money.

Choosing a CB antenna for your base station was not easy. There were plenty to choose from and they all had their pluses and minuses.

One of the most powerful, yet most frustrating was the ever popular Moon Raker. This was a beam antenna that looked very similar to TV antennas, most having 3 elements mounted on an 11 meter base. These were called regular Moon Rakers. However, there were beam antennas that had up to six elements on them. They were referred to as a Moon Raker 6. These things were huge. The problem with them was that they were directional antennas. What this means is that depending on what direction your antenna was pointing that was where you got your best reception and transmission. So if you were speaking to somebody who was south of you and your antenna was pointing north you had to turn the antenna 180 degrees in order to get a decent reception. This got to be a pain after a while. The plus side was that these antennas were so powerful they could cut through anything once you had your target zeroed in.

Another popular base antenna was what was called the “Big Stick”. This was really just a very long fiberglass antenna. They were usually about 10 to 15 feet long. They weren’t as powerful as the Moon Raker but they transmitted and received equally well in all directions and therefore were great all purpose base antennas especially if you were in a centrally located area where you had a number of people you could speak to in all directions. Also, Big Sticks were relatively cheap next to a Moon Raker that sold for a couple of hundred dollars. A Big Stick was about $70.

For people who didn’t have a very large budget, there were base station antennas made that quite honestly were not much more powerful than their mobile counterparts. When you take the lack of power of these antennas into account against their price tag of about $50, it made much more sense to go with a Big Stick.

The biggest problem with all of these antennas, especially in the old days, was that they were constantly interfering with TV receptions. Today with cable, things are not quite as bad.

Even though CB isn’t as popular with homeowners as it was 30 years ago, you can still see these bad boys on roof tops if you look close enough. Just make sure you stop the car first before taking a look.

It’s probably not something many people are interested in unless they’re some kind of an electrical engineer or just bored, but understanding how an antenna works can be useful when the one on your TV or radio goes south on you and the reason is beyond your comprehension.

Trying to explain how an antenna works in simple English is not an easy task as there are a lot of technical specifications that need to be explained. But a general understanding is possible without getting into tech speak that would make Einstein cringe.

In order for an antenna to work it has to radiate. Your antenna, whether TV or radio has what is called free electrons running through it. It is these free electrons that vibrate. The question becomes, how do these free electrons vibrate and what causes them to vibrate?

Well, in real life it takes an electric field to move an electron. If you take an isolated straight dipole, the power comes from the combined fields of all the charged particles, both positive and negative, in the antenna. We’ll call this field the antenna’s coulomb field.

In addition to this field, the antenna exhibits a magnetic field that is the sum of the magnetic fields of all the free moving electrons. The antenna also has a dynamic electric field that is the vector sum of the dynamic electric fields of all the free electrons. What we can do is separate the electric field of the antenna at any point in space into two components. One of the components will be in phase with the total magnetic field and the other will be 90 degrees out of phase. The in-phase component is the radiation field of the antenna and the out of phase component is the induction field. At the antenna, both fields are parallel to the metal surface.

What happens is that the coulomb field and the induction field fall off much more quickly than the radiation field as the distance increases from the antenna. When you reach distances greater than a few wavelengths from the antenna, you have what is called the antenna’s far field. This field is pure radiation. As you get closer to the antenna you have what is called the antenna’s near field. This field is a mixture of radiation, coulomb, and induction fields. Still with us? Great, we’re getting to the good part.

What ultimately happens with all these fields that makes it so that your TV or radio picks up signals through your antenna is this. The free electrons moving through your antenna are moving at their maximum speed. The right hand half of your antenna accumulates electrons. The left hand half of your antenna is where the electrons depart and leave an excess of charged ions. The coulomb field produces an imbalance and opposes the electrons’ rightward motion. The electrons then stop, coast for a bit and then head back towards the left. After they reach maximum speed they then stop and process is repeated, now heading back to the right. The result is a vibration of free electrons that heats the metal and in turn generates electromagnetic waves.

And that, in as simple English as possible, is how your antenna works.

If you were around in the mid 70s in the United States you’d have to have been living under a rock not to know about the great citizen band radio craze made popular by the smash hit “Convoy” by C.W. McCall. If you were into citizen band radio at all you knew that there was a certain prestige to having certain kinds of antennas, especially if you had a CB setup in your home.

For the mobile units, the ones that were installed in your motor vehicle, the antennas were rather simple and relatively weak. They could only send and receive a short distance depending on the time of day. In the afternoon, mobile CB antennas were lucky to reach a few miles, especially during sun spot time. At night, if you were lucky you could reach about 10 to 20 miles, maybe sometimes a little more.

Mobile antennas came in several types. One of the most popular antennas was the fiberglass model that hooked on the back bumper. These antennas were very good transmitters and receivers. Most were about 3/8 of an inch in diameter and about 2 feet tall. Some could handle up to 1000 watts of transmission power.

Another popular type of Mobile Antenna was the magnetic roof top antenna. These were not very powerful but they were real easy to hook up. Just pop the cable into your CB, which was installed usually under the dashboard in your car, and then just take the antenna, stick it out your window and pop it on your roof top. The magnet was strong enough that there would have to be a hurricane for that thing to blow off. These antennas could handle about 300 watts of power which made them a pretty low end antenna for CB use, but they were also very cheap.

Then we have the center load mirror mount antennas. The most popular of these were the Cobras. Don’t let these small things fool you. They could handle up to 3000 watts of power, usually made of 24 carat gold-plated 8-gauge copper coil. These antennas were also very expensive and today go for as much as $60 or more.

Of course one of the most common mobile antennas were the trunk mount CB antennas. These were very good antennas mostly because of the center placement on the vehicle towards the front of the trunk just before the back window. These antennas were not very expensive but usually were able to handle about 500 watts and because of their good ground, were very good for sending and receiving, even with a mobile unit that wasn’t that powerful. A good trunk mount antenna wouldn’t cost you more than $35.

There were some other odd brands of antennas but for the most part, these were the most common. They were relatively easy to hook up. In some cases, some drilling was required through parts of the vehicle to run antenna wire but for the most part anybody could put one of these things together.

Next, we’ll take a look at the most popular and powerful base antennas.