DX Engineering Four-Square Array Quarter Wave Tuned Cables ensure optimum pattern control and gain from your vertical antenna system. These cables are made from the highest quality waterproof PE jacketed, direct-burial RG-11/U 75-ohm low-loss foam coaxial cable. From each vertical antenna to the four-square system phasing unit, these phasing feedlines must be one quarter wavelength long electrically, which differs from the free-space dimension by the velocity factor of the specific cable type.
These cables, manufactured to DX Engineering specifications, have a velocity factor of 0.84, providing the maximum physical length to allow for easy burial and routing from the base of the vertical to the center-mounted controller. The electrical dimensions of these cables is critical to system performance. Solid dielectric cable would be less desirable for the array, as it has a lower velocity factor, resulting in a physical cable length too short to reach from the four-square system phasing unit to each vertical element. While it is possible to use 3/4 wavelength lines, they are not recommended as their use reduces bandwidth and can degrade system performance.
Choose array cables with RF beads if your vertical antenna feedpoints are elevated, or your vertically oriented wire dipole antenna feedpoints are elevated, and if the relay unit will be mounted in an elevated position. Array cables with RF beads will keep the feedpoint currents balanced and keep the cables from acting like radials, which could detune the antennas and distort the array patterns.
DX Engineering Four-Square Array Quarter Wave Tuned Cables are custom built by DX Engineering. Each are hand crafted and electronically tuned to a specific HF frequency. Typically, customers request that they are tuned to the center or slightly below the center of their antenna array band, depending upon their planned modes of operation.
After placing your order for DX Engineering Four-Square Array Quarter Wave Tuned Cables, please inform us of the desired frequency for your tuned cables by e-mailing firstname.lastname@example.org or by calling 800-777-0703 or 330-572-3200. You may leave a message after business hours. Custom cable assembly orders will process after we receive your frequency information. Please contact DX Engineering Technical Support if additional assistance is needed. We will contact you if we have any questions about your special order.