Choose Location
Choose a location for the DX-77-A in the clear,
away from trees, buildings, power-lines and other
metallic objects. The DX-77-A should be
attached to a steel mast or heavy aluminum mast
which is capable of supporting a structure of this
size. The DX-77-A does NOT utilize a ground
radial system, and the addition of ground radials
will NOT improve the performance. However,
high-conductivity ground in the immediate
vicinity will increase the gain by decreasing
ground losses.
WARNING:
Installation of this product near
power lines is dangerous! For your safety,
follow the installation instructions. Failure to
do so could
result in serious or fatal injury!
The mast height can be from 4 feet (1.2 m) to 10
feet (3 m). The recommended height is approxi-
mately 7 feet (2.1 m) . This puts the bottom
radials above eye-level and out-of-reach of most
children! A 10 foot (3 m) 2" O.D. steel mast set 3
feet (1 m) into concrete makes an ideal support.
The DX-77-A may also be mounted on a roof
tripod or on a tower structure, however, tuning
should be performed prior to installation. Since
wind survival is 60 mph, tower mounting is dis-
couraged. If you guy the support mast or tripod,
use non-metallic guy ropes.
A ground wire may be connected to the mounting
brackets (Item 15) for lightning protection.
Tools
R e q u i r e d :
Tape Measure, 12
feet
for
assembly, and
tuning
Nut
Driver,
3/8
inch
for
tuning
and
for assembly'
of matching
unit Nut Driver, 5/16 inch
for tightening
of
tubing clamps
2 each 'Open-End Wrench, 1/2 inch
for base
bracket assembly
2 each Open-End Wrench, 7/16
i n c h
for assembly
of
matching unit
An adjustable wrench may be' used in place
of the open-end wrenches.
Pre-Assembly
When unpacking your antenna, check all parts
against the parts list in the rear of this manual.
Read the instructions and study the illustrations
before beginning your assembly and installation.
The DX-77-A has been partially pre-assembled
for your convenience. Each trap assembly is
marked with a label: this label also indicates the
depth of insertion into the adjacent assembly.
The trap assemblies have frequency labels that
you can use as an approximate guide to tune
your DX-77-A to its resonant frequencies. If
these labels have worn off, or are missing, the
normal insertion depth is 3 inches (76mm)
The DX-77-A incorporates several improvements
over the original DX-77. Rain-caps are included
with the 17, 20, and 30 meter traps to prevent
detuning from rain, ice, and snow accumulation.
