Return to Home Page

S9v18 Vertical
Notes

Return to S9 Antennas

Antennas 

S9 logo

 

 

The S9v18 may be permanent ground-mounted and will require a 2 foot long, 1.5 inch 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 also roof-mount the antenna using a simple 3 foot tripod normally used for TV antennas. In this configuration, the antenna functions as a ground plane antenna and four, 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.

In lieu of an external antenna tuner in your shack, you can also use a weatherproof 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 feed point, 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).


Copyright 2011 Universal Radio, Inc.