Things that Work! The Select-A-Tenna testing conducted by Sam Coleman The Select-A-Tenna is an effective, compact AM radio antenna that uses no electricity and has no wiring to hook up. I was skeptical when I unpacked it. Could it possibly work? It had no batteries, no power cord, and maybe most mystifying of all, no wires to hook it up to my radio. The Select-A-Tenna is a working device and I'm indeed amazed. Physical Dimensions and Docs The Select-A-Tenna is 10.75 inches in diameter and 2.25 inches thick. It weighs 2 pounds. The exterior case is made from brown ABS plastic and has a large tuning knob in its center. It was well packaged and arrived in fine shape via UPS. Documentation was good and I immediately went to work testing the antenna in my system. INSERT PHOTO Test System The radio receiver used to test the Select-A-Tenna was a Sony multiband type, model ICF-6700W with built-in ferrite AM antenna. This radio is powered by the 12 Volt PV/battery system via a home made 9 VDC power supply. All measurements are directly taken from the signal strength meter on the Sony. Testing was conducted at Agate Flat, Oregon (42¡ 01'N. 122¡ 22'W.) at an altitude of 3,320 feet. With the exception of a chronically noisy 60 kiloVolt commercial power line nearby, this site is generally RF quiet. Using the Select-A-Tenna The thing is so simple to use that its a shame to have to talk about it. Just put the Select-A-Tenna within six inches of the radio's back or side, whichever place works best. That's it, no wiring! Since the Select-A-Tenna is a loop type antenna it is directional. By rotating the antenna and the radio's position in space, interfering signals can be reduced or even eliminated. Rotation of the radio/antenna system in space also increases the incoming signal strength. Test Results The table and graph below show my test results. The table contains three sets of data taken at three different times of day. The distance in miles between my receiving station and the AM radio station's transmitter were figured on longitude and latitude via the great circle route. This distance therefore represents the radio wave's shortest possible path. Improvement on the table was calculated as a percentage increase of the signal strength without the Select-A-Tenna. INSERT TABLE The Select-A-Tenna seems to work best on stations over 60 miles distant. Here signal strengths increase up to 525%. During the 11 AM test the Select-A-Tenna increased signal strengths an average of 228%. During the 5 PM test the Select-A-Tenna increased signal strengths an average of 170%. During the 10:30 PM test the Select-A-Tenna increased signal strengths an average of 45%. The Select-A-Tenna pulled out signals from the noise that were not even there without the antenna. It is also effective in reducing noise on audible signals, even strong ones. And the Select-A-Tenna allowed me to listen to to different AM stations on the same frequency without having them interfere with each other. A very interesting feature of the Select-A-Tenna is that you can rotate it to beam in signals from a particular direction. This is impossible with long wire antennas. How the Select-A-Tenna Works The Select-A-Tenna is a resonant loop antenna that is tuned with a variable capacitor. Orienting the loop so that the axis of its toroid is perpendicular to the incoming radio waves causes the loop antenna to focus the radio waves on the receiver's built-in ferrite antenna. According to the C. Crane Company, who makes the Select-A-Tenna, it produces a net gain of +30 decibels. Conclusions The Select-A-Tenna not only works well, but is amazing because it uses NO electricity or direct connection to the radio receiver. It is a good value at $46.95. Since it contains no transistors or active components, it should last a very long time. Since it lives inside, next to the radio, instead of outside in the weather, the Select-A-Tenna may last forever. I recommend it to any AM radio junkie. Access The Select-A-Tenna is manufactured by the C. Crane Company, 147 Watson Lane, Fortuna, CA 95540 ¥ 707-725-5940