Acquired in 2014 by Alpha Antenna, the S9 Antennas have been completely improved and resigned. 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 6-160 meter base antenna even in HOAs.
The S9 is a 43 foot element in a 38 foot mast that is tough, yet ultra-lightweight (3.5 lb) vertical that can be user configured in many ways. For example, it can be configured as, a) multi-band antenna from 160 through 6 meters by installing the optional Alpha S9 Match at the antenna base, b) a base fed vertical for 40 meters and the third harmonic of 15 meters, c) or re-configured as the pictures below have been done by other users.
Advantages of the S9 over other options:
• It is important to know that the manufacturing process used for the Alpha S9 Antenna is one where the tapered fiberglass is spun.
• Rubber caps, rather than breakable plastic caps, are firmly affixed while the S9 is stored and transported.
• The length of the mast is optimized at 38 feet.
• Inside the mast is a 43 foot 13AWG wire element that can be fed to the optional external Alpha S9 Match to enable the S9 to be used as a 6-160 meter multi-band antenna
• The 43 foot element can be optionally trimmed to a resonant 40 meter length of approximately 34 feet, which would be an approximate 1/8 wave on 80 meters, full wave on 20 meters, two wave-lengths on 10 meters, and the third harmonic of 40 meters, which is 15 meters.
• Wiring is a 13AWG military grade wire element that has little or no memory, which also has a slick outer sheath so that it can easily slide up and down through the center of the mast with absolutely no chance of catching or kinking.
• The color has been selected as to reflect the natural surroundings allowing it to have the appearance of changing color to be a very stealthy option for HOA environments. Additionally, the green tint enables it to be hidden amongst foliage, where also it is dark enough to be hidden fairly well in trees where only the brown/tan bark exists when leaves have fallen. • The collapsed length of the S9 is 46 ½ inches.
The S9 is constructed of rugged tapered spun fiberglass, weighs just 3.5 pounds, and is double insulated for the safety of your family and neighbors, which can be mounted on the ground or on your roof.
Permanent ground-mount installations require a 40-inch long, approximately 1.5″ (1.8″ OD Max) galvanized steel pipe. The S9 base tube simply slips over the pipe for a simple and elegant deployment. (A mechanical connection from the antenna base tube to the pipe is neither required nor desired.)
Because the S9 is so light, you can roof-mount it using a simple 3′ tripod that would normally be used for mounting TV antennas. In this configuration, the S9 functions as a ground plane (GP) antenna and four, wavelength radials are required for each band of operation.
When used with a good RF ground, the S9 is a serious 40 meter DX antenna. With only a tuned wire installed, the natural resonant frequency of the antenna is on the 40 meter band – and it is extremely broad banded. Depending on your ground system and proximity to nearby objects, the S9 will exhibit an SWR well below 2:1 on the 40 meter band without an antenna tuner.
So, if you primarily operate SSB on 40, you will be able to tune the S9 on 40 meters without an antenna tuner. In this configuration, the coax feed line can be directly connected to the antenna. Radials and a 1:1 current choke balun are recommended. There are several commercially-available 1:1 choke baluns available (Balun Designs, etc. are some suppliers to consider) or you can create a simple choke balun using your coax feed line.
Internal rig tuners will then be able to easily tune the S9 anywhere on 40 meters. But if you want to use the S9 as a multi-band antenna, you will need a quality antenna tuner in your shack or remotely located at the antenna feed point. Note – Some internal rig tuners may only work for SWRs of less than 3:1, so you will want to test your installation before relying on whether a rigs internal tuner is sufficient.
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.
Loading coils can be built by the user to extend the natural resonant range of the antenna. For example, to enable excellent 80 meter coverage, an 80 meter coil can be easily constructed with 15 turns of #12 AWG insulated wire on a 3″ PVC coupler.
Ziteng (Andy) Wang is a PhD student at the University of Sydney. He recently discovered an unusual radio signal coming from the direction of the Milky Way’s center. The radio waves Andy discovered using the ASKAP radio telescope in Western... Read more
The LoRa Meshtastic T-BEAM device are small battery powered devices that will mesh with other T-BEAM and send messages and other data from your phones... Read more