Download the S9v 18' Junior Installation Guide
The S9v 18' Junior is a tough, yet ultra-lightweight vertical designed for Amateur Radio use
from 20 through 6 meters. The S9v Junior is constructed of rugged tapered fiberglass, weighs
under 2 pounds and is double insulated for the safety of your family and neighbors.
The S9v Junior can be mounted on the ground or on your roof.
- Permanent ground-mount installations require a 2 foot long, 1” OD MAXIMUM galvanized
steel pipe. The S9v Junior 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 S9v Junior is so light, you can roof-mount the antenna using a simple 3'
tripod normally used for TV antennas. In this configuration, the S9v Junior functions as
a ground plane (GP) antenna and only 4 radials, each ¼ wavelength at 14 MHz (16 feet,
9 inches long) are required.
Since the S9v Junior 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 S9v Junior 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 100
feet.) A 1:1 choke balun is recommended at or near the antenna feed point to prevent RF
from entering your shack via the coax outer shield. There are several commercially-available 1:
1 choke baluns (Balun Designs being one of the best) or you can create a simple choke balun
using your coax feed line.
If you want to use the S9V Junior as a multiband vertical, you will need an external antenna
tuner in your shack and a 4:1 unun at the S9v Junior feed point.
Internal rig antenna tuners do not have adequate range to match the higher impedances
presented by the antenna on frequencies above 20 meters. We recommend the LDG
Electronics series of auto tuners for use with the S9v. LDG tuners easily handle the wide-
range of impedances presented by the S9v over the higher HF frequencies.
A 4:1 unun lowers the higher impedances presented by the S9v on frequencies above 20
meters and also helps isolate RF currents from your coax feedline. Balun Designs
manufactures two 4:1 ununs specifically for S9 antennas. You have two choices, depending
on the amount of power you expect to run with the S9v Junior:
Finally, In lieu of an external antenna tuner in your shack, you can also use a weatherproofed,
remote antenna tuner at the S9v Junior 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 S9v Junior feedpoint, a 4:1 unun is not required. However, you
may need a 1:1 current choke balun between the tuner and your transmitter 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 S9v Junior 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 S9 Radial Plate (or, our new PRO Plate) to connect and organize your ground radials.
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- Fully Assembled
- Full 1/4 Wave Performance on
20 Meters - Tapered Telescoping
Fiberglass - No Lossy Traps or Coils
- Ultra-Light and Super Slim;
Weighs Under 2 lbs - Perfect for Home or Portable
Use - Deploys in 5 Minutes or Less
- Collapses to 45"
- Unique Double Insulated
Design - Safe for Children and
Pets - No Corrosion; Weather-Proof
- No Hose Clamps or Messy
Joint Chemicals - "Neighbor-Friendly" Forest
Green or Black Matte Finish
S9v 18' Junior Multiband Vertical
for 20 - 6 Meters
for 20 - 6 Meters
(Click for full-size image)
