DX-SWL Shortwave Sloper Antenna
Multi-Band Performance covering Medium Wave AM (.5-1.6 MHz),
120 MTRS(2.3-2.5 MHz), 90 MTRS (3.2-3.5 MHz), 60 MTRS (4.75-5.0 MHz), 49 MTRS (5.95-6.2 MHz), 41 MTRS (7.1-7.3 MHz), 31 MTRS (9.5-9.9 MHz), 25 MTRS (11.65-12.05 MHz), 21 MTRS (13.6-13.8 MHz), 19 MTRS (15.1-15.6 MHz), 16 MTRS (17.55-17.9 MHz), 13 MTRS (21.45-21.85 MHz)
The Model DX-SWL antenna is a very unique and very effective adaptation of existing antenna theory. It operates as quarter wave sloper which means the wires are a quarter wave long, or multiples of a quarter wave on each frequency band. Compared to half wave dipole, the other quarter wave, which is necessary for performance and the proper feed point impedance, is made up of the "Down-Lead" wire which is attached.
With a quarter wave sloper, the center conductor of the coax is attached to the wires and the shield of the coax is attached to the down lead. A standard SO-239 UHF connector is provided on the Model DX-SWL for this purpose. Excellent performance is attained with installation heights of only 20 to 40 feet.
By design, the quarter wave sloper is known to be an excellent DX and long haul antenna. The current lobe, which defines the major radiation characteristics of the antenna, is up high at the feed point and is not subject to attenuation from buildings, trees, etc. as a vertical antenna whose current lobe is at ground level. At the Alpha Delta location, side by side comparisons between the Model DX-SWL and a 32ft commercial vertical with 18 radials show the DX-SWL to be as much as 10 dB stronger into Europe and Africa.
Since a sloper has an optimized low angle radiation pattern for peak DX performance, it will greatly outperform a dipole mounted at the same height, for those really distant weak signal DX stations. The difference can be phenomenal.
The Alpha Delta Model DX-SWL is fully assembled, uses stainless steel hardware and UV protected coils and components and No. 12 wire. It is designed to survive severe weather environments. Insulators and support rope are included.