The TZ-RD-1740 is a rotary Vee dipole antenna designed to permit operation on the 10/15/20/40m bands. The antenna is primarily designed as a trapped and loaded dipole. 2 traps per band are used to isolate the remainder of the element for use on each particular band.
The antenna is full size on 10m and therefore has effectively 0 dBi gain on that band. Since loading is halfway along each element losses are minimised since the current in that antenna is much less than at the feed. For 40m the antenna is almost 60% of full size and performance is only slightly less than that of a full size antenna, without the mechanical difficulties. On 15m and 20m the antenna is a operating in a range where 1-2dB loss of a full size rotary dipole can be expected.
The slight Vee configuration ensures that there is some vertical radiation component and therefore extreme nulls off the side of the antenna are not present although there is some directionality. A rotator is not required but may be used to enhance signals when they are from the side of the antenna.
BLOCK SIZE & MOUNTING CONSIDERATIONS
The TZ-RD-4 can be mounted 1 or 2 meters above (parallel to the boom – i.e offset 90 deg) above your existing tribander to permit coverage of the Low bands or as a simple antenna for the new ham to HF operating. A turning radius of at least 7.5m is recommended as the total length of each side of the antenna is 7.1m (total 14.2m wing span).
The TZ-RD-4 is designed as a high performance DX antenna for 40m and therefore needs to be mounted at height and in the clear. A minimum installation height of 10m is required, and for DX performance on 40m and installation height of at least 15m is recommended.
ANTENNA DESIGN AND COMPONENTS
The TZ-RD-4 uses 6 coaxial traps and 2 capacity hatss that are not affected by rain since the coils sections are sealed. Acetal plastic insulating sections are used for mechanical strength and stiffness so that the antenna is subject to minimal sag. The center sections of the antenna are 32mm O.D, tapering down to 10mm O.D. at the tips . Stainless steel fasteners are used throughout as well as aluminum rivets for reduced corrosion. Eight (8) stainless steel hose clamps are used to permit adjustment of the antenna on each band. Assembly is simple and straightforward, and if by chance something does go wrong most parts can be obtained from your local hardware store, e.g. nuts, crews, rivets, U bolts etc.
The Rippletech TZ-1840 balun is recommended for feeding the antenna with low loss across the bands.
The TZ-RD-4 is supplied with all stainless steel hardware except for the boom/pole mount U bolts (optionally S/S).