Improving Reception of KAFM 88.1 on Your Home Radio

First -- A Little Background

KAFM has a licensed power of just 16 watts. As a result, our signal strength is relatively weak. We are able to cover the area as well as we do because our transmitter is located high above the area on Black Ridge, a BLM administered area above the Colorado National Monument.

FM radio signals travel only through free space and cannot penetrate obstacles (such as buildings) very far. If you live in an area where you cannot see the Black Ridge blinking red tower lights from our transmitter, you are picking up KAFM via a reflected signal, a signal which has bounced off nearby objects that do have a clear line of sight. These reflections can sometimes create a problem called multipath interference. Multipath interference occurs when two or more signals arrive at your radio at the same time.

If you can pick up KAFM on your car radio at your home, there are steps you can take to improve the reception of your home radio. Car radios have a much-improved signal gathering strength compared to most home radios. The addition of a better antenna system should improve your home radio reception.

Your Antenna Kit

The antenna kit contains a dipole, T-type antenna which is designed to improve the reception of FM signals. When installed, the antenna system will look like one of the following:

The antenna is attached to the antenna lead in on the back of your radio. Before you hook up the dipole antenna, there are two things you need to determine. One is which style of antenna connection you have on your radio, and the other is the ohm setting on the antenna connection.

Let's start with the style of the antenna connection for your radio. The connection will be marked “antenna” or “ant” and will be one of three types:

having two screws to attach the antenna wires;

having a single screw-in connection;

where the antenna wires are inserted into small locking holes.

FM radio receivers have either a 75-ohm (ohm, a unit of resistance, not a chant) or a 300-ohm antenna connection. This number should be marked at the antenna connection.

The dipole antenna provided to you is a 300-ohm device. If you have a 300-ohm antenna connection on your radio, the dipole antenna can be connected directly. If you have a 75-ohm antenna connection, which looks like a cable TV connection, you will need to install a matching transformer which provides the conversion from the 300-ohm antenna to your 75-ohm antenna connection. These can be obtained from KAFM.

If your home radio does not have a separate antenna connection but utilizes a silver telescoping antenna, don’t get discouraged! You can still utilize the dipole antenna to improve your reception.

Installing the Dipole Antenna

The dipole antenna will provide the best reception if it is located on either a south or a west facing wall. Ideally, the two arms of the dipole should be at right angles to the direction facing Black Ridge. If you can place the antenna on an outside wall and near a window (so that the number of barriers between the antenna and the signal are minimized), your chances of good reception will be improved significantly.

The connection end of the dipole should be attached to the antenna connection on your radio. When you called for the antenna kit, we asked you which type of antenna connection you have and, hopefully, the antenna provided will match your connection.

For a screw-type connection: Loosen the screws at the antenna connection on the radio and slide the spade lugs in under the screws and tighten.

For a coaxial connection: Simply screw the connector to the antenna connection on your radio.

If you have a wire-insert connection: You will have to clip off the spade lugs provided and strip the insulation from the ends of the antenna wires back about ½ inch. Flip up the tabs on the edges of the antenna connection, insert the wires and close the tabs to secure the wires in the bracket.

The two arms of the T-shaped dipole should then be attached to the wall using map tacks or small brads. Make sure the two arms of the T are fully extended. Generally, the reception will be best if the dipole is mounted high on the wall, but it can also be placed lower on the wall or even on shelving if you are concerned about the appearance. You may have to experiment with the placing of the dipole and the direction it faces to find the best location for optimum reception.

TIP: Keep your radio and antenna away from devices that generate Radio Frequency Interference (RFI) like computer monitors and fluorescent lights.

If your radio has a silver telescoping antenna: Attach one of the wires from the dipole antenna to the silver alligator clip provided. The alligator clip is then clipped to your telescoping antenna.

Additional Improvements You Might Try

Sometimes reception improvements can be gained by switching your radio from the Stereo to Mono mode if your radio has that capability.

You can try a different type of antenna than the simple dipole. There are indoor, amplified antennas that you can obtain from Radio Shack or electronic equipment stores like Circuit City. The amplified antennas can cost anywhere from $25 to $50. Be sure to purchase these with the agreement of the store that they can be returned if the FM reception is not improved.

You can install an outdoor external antenna that mounts on your roof or in your attic. The yagi antenna is probably the best for FM signal reception. Radio Shack has yagi antennas, like the Six Element Triple-Drive Antenna, that look very much like the rooftop TV antennas. These can be obtained for as little as $20. If you purchase this type of antenna, make sure that it is designed to receive FM signals. Some antennas used for TV reception block FM signals. These antennas are fairly high directional antennas and when installed, should point directly at Black Ridge.

And, Finally...

We hope these suggestions and the antenna kit have been able to improve your reception and listening enjoyment of KAFM! If you have any questions, or need further help, please give us a call at 241-8801, ext 201. If need be, we will come out to your home or business and see if we can help.