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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.

Hard drives come in many different sizes and configurations. How much data a hard drive can hold is measured in gigabytes (GB). The latest hard drives can hold anywhere from 80 GB to 1000 GB (1 TB)! When buying a hard drive, size isn’t the only factor to look at, however. By choosing the right hard drive for your needs, you’ll enjoy your computer more. Hard drives are inexpensive and you should never skimp on one to save money.

For business or basic home use, an 80 GB hard drive should suffice. If you plan on downloading music, movies, or installing a lot of games on your computer, your hard drive should be at least 160 GB. For laptop users, the same space requirements apply, however, many laptops come with small hard drives. Many laptop users choose to keep the small hard drive and buy an external hard drive for excess files to keep costs down.

You can have a huge hard drive, but it will be worthless if it doesn’t move data fast enough for your computer! To find data, hard drives have platters on spindles that spin, similar to a CD. How fast a hard drive spins is measured in RPM (revolutions per minute). The higher a hard drive’s RPM is, the faster it will perform. Desktop hard drives almost always have 7200 RPM hard drives. Laptop hard drives can range from 4200 RPM to 5400 RPM for budget and midrange uses and 7200 RPM for high end use. Hard drives with RPMs of 10,000 or more are available, but those are mainly for gamers, computer enthusiasts, and servers.

If you are computer user looking for performance, you should know about RAID. RAID lets you put 2 or more hard drives of the same brand and model together and run them at once, which results in faster performance. You can also use RAID so the second hard drives automatically backs up data from the first hard drive, so you always have a backup of your data. There are numerous possible RAID configurations out there, too many to mention in this article.

A hard drive’s cache is also another important performance indicator. A hard drive’s cache will hold frequently accessed data for faster access by the computer. A good hard drive will have at least 8 MB of cache. As with RPM, the more cache a hard drive has, the better.

Hard drives generally have either an SATA or IDE connection. Both connections are for attaching the hard drive to the motherboard via a cable so that data can be sent and received to and from the computer and drive. SATA is the newest connection and is better than IDE in that it can be faster and uses a much smaller cable. IDE, however, is just as fast as IDE in real world performance testa and hard drives that use IDE are cheaper than SATA hard drives. However, IDE hard drives use large cables that can restrict airflow. Fortunately, you can buy a rounded IDE cable that is not as big for $5-$10 at almost any computer supply store or online computer part retailer