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Home » Products » Discontinued Misc » S9v18 Vertical Antenna » Description

S9v18 Vertical Antenna


The S9v18 is a tough, yet ultra-lightweight vertical designed for Amateur Radio use from 20 through 6 meters. The S9v18  is constructed of rugged tapered fiberglass, weighs under 2 pounds and is
double insulated for the safety of your family and neighbors.

Our  design features UV-resistant, high-tech polymer tube rings that quickly slide on and off the antenna, allowing lightning-fast "tool free" deployment of the antenna at home or in any field environment.

The S9v18 can be mounted on the ground or on your roof. 

  • Permanent ground-mount installations require a 2 foot long, 1 OD Max galvanized
steel pipe. The antenna 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 S9v18 is so light, you can roof-mount the antenna using a simple 3' tripod
normally used for TV antennas.  In this configuration, the antenna functions as a ground plane (GP) antenna and four, one-half wavelength radials are required for each band of operation.

Since the S9v18 is close to a full quarter-wave vertical on 20 meters, it can be used as a superb 20 meter DX antenna using the antenna tuner inside your rig (or with an external antenna tuner in your shack).  In this configuration, the antenna may be ground or roof mounted and fed directly with a high quality 50-ohm coaxial feed line such as RG-213 or LMR400.  (RG-8X is also adequate for portable operation and base station runs under 50 feet.)   A 1:1 choke balun is recommended to prevent RF from entering your shack via the coax outer shield. If you want to use the S9v18 as a multi-band vertical, you will need an external antenna tuner in your shack and a 4:1 Unun at the antenna feed point.

Finally, in lieu of an external antenna tuner in your shack, you can also use a weatherproofed, remote antenna tuner at the 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 feedpoint, a 4:1 unun is not required.  However, you may need a 1:1 current choke balun 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 S9v18 should be used with at least 16 radials (32 preferred), with each radial at least 13 feet, 5 inches long (0.2 wavelength at 14 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 13 feet, 5 inches in length (or longer) should be considered to ensure top performance.  It is highly recommend that you use the optional S9RP Aluminum Radial Plate to connect and organize your ground radials.