( ) Wind and RF choke and attach to the phasing harness as shown in Figure 5. The
choke shouldconsistof 12 turns of RG-8/ u coaxial cable wound in a circle with an 8" side
diameter. Attach the center conductor of the choke to the center conductor of the top
phasing line.Att~RQthe choke braid to the centerc;onduc;tqrof the bottom phasing line.
Attach the othercendof the RF choke to the' transceiver:
"' <:": ":,~::,;.:,::"":_":.,:,, , ", ' ' : :.f~
For optimum band pas~·§.rt~signal gain,itis nOJcomtnendedthat a Hy-Gain Model BN-27 A
balun be used.
( ) Securely tape all exposed portions
of
the coaxial braid to prevent it from shorting out
ort the antenna. Weatherproof allcoaxial connec;Jionswith Pli-O-Bond, Neoprene or some
sirnilar substance. .
() MOlJntthe antenna on a 1
%
cable to allow 360
0
rotation.
Installation
Procedures
When installing the assembled Model SDB6, there are several items to consider. The
close proximity of metallic objects can seriously deteriorate the performance of any
antenna. For best results, mount the antenna at least 20 feet away from power lines, TV
antennas or any existing metallic objects. The recommended installation method, using a
self-supporting tower, is shown in Figure 7. If the tower requires guy wires, they must be
broken up with strain insulators every three feet. As an alternate method, the antenna may
be mounted on the roof-top as shown in Figure 8. (Optimum results may not be obtained
due to metallic objects such as rain gutters, house wiring, etc.) Ifthis method of installation
is used, the mast material must be 1
%
heavy walled material. Mount the antenna a
maximum of one foot above the rotator and guy the mast directly below the rotator. Use
three guy wires equally spaced and be sure to break them up every 3 feet with strain
insulators. Install the guy wires so there is a minimum of 2 feet of clearance between the
guys and the lower tip ofthe antenna element. This minimum of 2 feet of clearance and the
use of strain insulators applies to all installation methods using guy wires.
For proper lightning protection and to insure noise free performance, the supporting
structure must be properly grounded. Use a W' x 8"ground rod driven into the ground as
close as possible to the base of the supporting structure. Connect the ground rod to the
supporting structure using #10 or larger copper or aluminum wire.
NOTE: The boom-to-mast brackets have a hole through their centers to allow securing to
the mast with the 5/16"-18 x 3W' bolt. It is recommended that the mast be removed and an
11f32"i h()lebe'dr1l1ed atlhedesired mastposit1on,,~hen rein~tall the mast. If this is not
possible, the clamp will hold its position on the mast in all but the most severe weather
conditions.
