10-80 METER ALPHA S9 PORTABLE AND BASE ANTENNA
Acquired in 2014 by Alpha Antenna, the S9 Antennas have been completely improved and redesigned. Years of perfecting the manufacturing process, length, and color has enabled Alpha Antenna to offer a spun fiberglass antenna mast that is so resilient & stealthy that it can be used as a base antenna even in HOAs.
The S9 is a tough ultra-lightweight (3.5 lb) antenna that can be user configured in many ways (see pictures below). For example, it can be configured as, a) multi-band antenna from by using the wire element inside of the side of the 31 foot mast. It can even be connecte to an optional Alpha S9 Match to increase bandwidth.
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The S9 is constructed of rugged tapered spun fiberglass, has a collapsed length of just 43 ½ inches, weighs just 3.5 pounds, and is double insulated for the safety of your family and neighbors.
For multi-band use, the Alpha S9 Match is recommended at the antenna feed-point. This lowers the higher impedances presented by the antenna on frequencies above 40 meters and can provide coverage that enables 80 meters to be tuned.
If you are using a quality antenna tuner and have a coax run under 50 feet, a 1:1 current choke balun located outside of the radial field may be needed if common mode current is experienced.
Finally, in lieu of an antenna tuner in your shack, you can use a weatherproofed, remote antenna tuner at the S9 feed point for absolute lowest loss and best over-all multi-band performance. There are several remote antenna tuners on the market. When a remote tuner is used at the antenna feed-point, a 1:1 current choke balun may be needed between your transmitter and the antenna (outside of the radial field) if you experience RF current in your shack. (Burying your coax cable also helps minimize RF current from flowing back into your shack.)
For optimum performance, a ground-mounted S9 should be used with at least 16 radials (32 preferred), with each radial at least 26 feet, 9 inches long (0.2 wavelength at 7 MHz). Actually, there is no precise formula to calculate ground-mounted radial length because everyone has different soil and soil tends to change the electrical length of the radials. However, a general rule of thumb for radials is: longer and more is better. If you have the time and resources, 32 or more radials each at least 26 feet, 9 inches in length (or longer) should be considered to ensure top performance.