Hy-Gain 2BDQ-S User Manual
ORDER NO. 380S
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Model 2BDQ-S
Trap Dipole Antenna
INSTRUCTION MANUAL
General Description
The Hy-Gain Model 2BDQ-S is a 1/2
wavelength, dipole antenna for 40 and 80
meters. Band switching is accomplished
automatically through the use of two matched
Hy-Gain 40-m eter Hy-Q t raps. The maximum
overall length is 100' 10 1/2". If the antenna
is mounted in an inverted "V" configuration,
the overall length will be shorte ned.
The balun will improve the performance and
efficiency of the 2BDQ-S. The Hv-Gain
Model BN-86 is a broadband balun designed
specifically for dipole-type antennas. The
balun balances the input impedance to the
antenna and prevents transmission line
radiation.
Theory of Operation
Matched Hy-Gain Hy-Q traps give true 1/2wave resonance. They are tuned at the factory
and no adjustments are necessary. They
operate as a high impedance circuit on 40
meters and add to the overall length of the
antenna as center loading for the 80/75 meter
resonance.
Construction
The Hy-Q traps will withstand h ard wear and
severe weather conditions. All hardware is
passivated stainless steel. The center of the
dipole is supported with a yoke-type center
insulator to which the transmission line
attaches. The ends of th e dipole are suppo rted
by two end insulators constructed of high
impact ABS plastic. The antenna wire is
Alumoweld© #12, which resists rust and has
a breaking strength of 1200 pounds.
SWR and Feedline
The 2BDQ-S antenna is designed for use with
single 50 ohm coaxial feedline. The SWR at
resonance is 1.5:1 or less on both bands.
Alumoweld® is a registered trademark of Copperweld
Bimetallic Grou
Assembly Procedure
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Referring to Figure 1, place one half of the
center insulator (Item No.7) on a flat surface
with the inside facin
.
Assemble the hardware on the eyebolts an
lace in the insulator.
Figure 1 Ass embl y of Antenn a Wi re to Cent er
Insula tor
Strip the coax and s eparate the center condu ctor from the braid. Solder the braid to one
solder lug (Item No. 22) and the center
conductor to the other solder lug. For a
smaller coax , a reducing sleeve is provided.
Apply silicone gr ease or V aselin e®, etc . (not
supplied) to the matin g halves.
Place the halves together and secure them
using the #6-32 x 3/8" bolts and nuts (Item
Nos. 15 & 16).
Hold the eyebolt to keep it from turning and
tighten the 1/4" nuts on the outside, first one
NOTE: Both sides of the antenna are exactly
the same. Each of the following steps must be
done first for one side then repeated for the
other side.
Cut the 40-mete r wire (LI) to eithe r Phone or
Continuous Wave (CW) dimensions as shown
in Figures 2 and 3. Add an extra thr ee inches
on each end for attaching to the center
insulator and 40-meter trap. Example: Ll
length for CW operation is 19' 8 1/4". Add
six inches, three inches each end, which
makes a total length of 20' 2 1/4". Each
insulator or trap requires three inches for
proper attachm ent.
NOTE: When you have selected your mode of
transmission (Phone o r CW), you must us e the
same mode for all dimensions .
Attach one end of the wire (just cut) to the
center insulator (Item No.7) using the wire
locks as shown in Figure 1. Do not forget to
connect th e pigtail to the wire lock.
Clip off all excess wire extendin g past the
wire lock.
Select the 40-meter trap and the trap
connector clamps. Assemble the clamps on
both ends of the trap using the #10-24 x 1
1/2" bolts, lockwashers, and nuts (Item Nos.
9, 11, and 10), as shown in Figure 4.
Carefully remeasure the antenna wire connected to the center insulator and bend the
wire for attachment to the 40-meter trap as
shown in Figures 2 and 3.
Connect the wire to the trap using the wire
locks (Item No. 5) and shown in Figure 4.
Clip off all excess wire extending past the
wire lock.
Figure 2 Antenna Wire
is a registered trademark of Chesebrough -Ponds,
Measurements
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