DX Engineering TFS4 Series B Transmit Four-Square Systems bring together the highest level of engineering excellence with the practical realities of operator convenience and ease of installation. These four-square series hybrid systems are available in versions for the 160, 80, and 40 meter bands. They can be easily dropped into your quarter wave spaced vertical 4-antenna array to provide optimum directional control. They allow the operator to receive or transmit with 5.5 dB gain in any one of four directions with a 20+ dB front-to-back ratio for interference reduction from unwanted directions. You can also switch to a single Omni-directional pattern with a push of a single button. This combination permits you to listen "all-around," unhindered by pattern nulls, and then select the best direction for signal reception and noise rejection.
The TFS4 Series B Transmit Four Square Systems are designed for use with a four monoband vertical antennas spaced at the corners of a square that are a quarter wavelength on a side. The vertical antennas must be ungrounded and resonant in the desired band, and should be directly base-fed by the coaxial cable phasing lines from the centrally located controller. DX Engineering has vertical antennas that are well suited for this application. Above all, a properly designed and installed radial system is necessary for top antenna performance, whether it's a single vertical or a full array.
DX Engineering strongly recommends our optional Q75- series quarter wavelength cables constructed from our own high quality DXE-11U waterproof PE jacket, foam dielectric cable that has a velocity factor of 84 percent. These cables are electronically pruned to a precise electrical length derived from your choice of center operating frequency, terminated with hand-soldered silver-PTFE PL-259 connectors and weather-sealed with shrinkable tubing. Finally, each cable is tested for high voltage breakdown for maximum reliability and power handling. Since the transmit power is divided by the controller, the coaxial cable can handle maximum power with ease.
If you already have a four-square array with a hybrid controller and would like to upgrade to improved performance and the Omni feature, the DX Engineering TFS4 Series B Transmit Four Square Systems are a direct transplant. BCD logic switching allows for the use of a 4-wire control cable to perform the necessary switching functions when powered by the included control console.
* Classic hybrid design is easy to install
* Four directions plus Omni for versatile operation
* 5 kW CW power rating for high reliability
* Hot switching lock-out to disable amplifier while switching
* Drop-in replacement for COMTEK systems
* Proven DX Engineering RF relays for high performance
* RF Shielded, high impact thermoplastic cover offers unique protection
* Relays cycle during Power-On to ensure clean contacts