The DS144-6RS is a new high performance yagi antenna design. The idea was to design a yagi that was optimized for DX work at the low end of the two meter band, but with a compact footprint so that it would be "street legal" when assembled and driving down the nation's highways. The DS144-6RS has been carefully checked out in the real world to ensure accuracy of the design effort. This antenna provides maximum gain at about 144.5 MHz and starts to drop off above 145 MHz. You would not want to use this yagi for FM! It is much more suited for VHF contesting rover operations as well as liason duty for 5 and 10 GHz weekends and cumulative contests. Forward gain is the most desired characteristic with this antenna. It actually delivers more gain than competing designs that are one foot (or more) longer, while at the same time preserving a good pattern in both the "e" and "h" planes. The net result is wide beamwidth, and clean lobe structure coupled with a very high gain figure. Clean H-plane patterns translate to efficient stacking with maximum possible gain and manageable array sidelobes, should you wish to stack these antennas in a larger array.
All Directive Systems antennas are verified for proper performance on an antenna range with state of the art swept measurement equipment to record the results. Some performance curves have been provided below on these pages.
The DS144-6RS specifications (and manual) are listed here.
The DS144-6RS yagi employs a traditional modified T match and half wave balun to match your 50 ohm feedline to the driven element. The T match provides a great method for achieving proper match along with exemplary decoupling of the feedline from unwanted antenna currents. Poor decoupling efforts can reduce gain by large amounts. If any power flows on the outside of the coaxial cable, or along the antenna boom, gain or efficiency suffers drastically. Poor decoupling will show up as varying VSWR as the feedline is handled. Deep response nulls within the passband of the yagi are a tip off as well. Any skewing of the main lobe off the boresite heading indicates out of control rf currents caused by poor (or no) decoupling. A sample close up of a typical T match is shown here. The actual antenna is a 432 yagi and it presents a more compact photo that shows maximum detail. The 144 MHz T match looks similar, just bigger!
SAMPLE DRIVEN ELEMENT T MATCH DETAIL
The DS144-6 computer modeled patterns are here: