ORDER NO. 380S
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-meter Hy-Q traps. The maximum overall length is 100' 10 1/2". If the antenna is mounted in an inverted "V" configuration, the overall length will be shortened.
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 1/2- wave 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 hard 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 the dipole are supported 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.
RG58/U or RG213/U is recommended.
Alumoweld® is a registered trademark of Copperweld Bimetallic Group
Assembly Procedure
Referring to Figure 1, place one half of the center insulator (Item No.7) on a flat surface with the inside facing up.
Assemble the hardware on the eyebolts and place in the insulator.
Figure 1 Assembly of Antenna Wire to Center Insulator
Strip the coax and separate the center conductor 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 grease or Vaseline®, etc. (not supplied) to the mating 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 side and the other.
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-meter wire (LI) to either Phone or Continuous Wave (CW) dimensions as shown in Figures 2 and 3. Add an extra three 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 attachment.
NOTE: When you have selected your mode of transmission (Phone or CW), you must use 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 the pigtail to the wire lock.
Clip off all excess wire extending 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
Measurements
Vaselinc is a registered trademark of Chesebrough -Ponds,
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