Hy-Gain UB-7031DX Instruction Manual

INSTRUCTION MANUAL
GENERAL DESCRIPTION
The Hy-Gain Model 70-31 DX is a high-perfor-
mance yagi antenna for SSB/CW DX'ing in the
Amateur 70 cm band.
It features 31 elements on a 24 foot (10.4
wavelength) boom, with the ultimate in high gain,
low sidelobes, and high front-to-back ratio. It also
features an encapsulated feedpoint and a
weatherproof type N connector for use in all
types of climates. The usable frequency range of
420438 MHz makes the 70-31 DX suitable for
432 MHz EME and terrestrial DX, 435-437 MHz
satellite communications, and 420-430 MHz
ATV The 70-31 DX antennas may be easily
stacked for increased performance.
ELECTRICAL DESIGN
The 70-31 DX design is based upon the DL6WU
log-tapered design information, with enhance-
ments to the gain, sidelobe levels, and front-to-
back.
Model UB-7031DX
70 cm / 31 Element Yagi
for SSB/CW DXing
Performance was verified by testing on Hy-Gain's
antenna range and by computer modelling with
the NEC-3 and YO-4 codes. The antenna's perfor-
mance characteristics were optimized for the 432-
436 MHz frequency range. This improves the
antenna's performance in rainy, icing and snowy
conditions at 432 MHz.
MECHANICAL DESIGN
The 70-31 DX mechanical design features a 6-
section boom which can be easily disassembled
and reassembled for portable operations. An
adjustable 7/8" and 1" O.D. tubular boom support
is included to reduce boom droop when using
heavy, low loss coaxial cable or under severe
icing conditions. The boom-to-mast bracket and
boom support can be adjusted for best balance in
an EME array. The boom support may be
installed above or below the boom.
Most hardware is stainless-steel including the ele-
ment retaining rings (pushnuts). All insulators are
UV protected. The coaxial balun assembly is
made from high-quality RG-303/u and RG-142
B/u PTFE dielectric and FEP jacketed coaxial
cable.