TZ-RD-3W

12/17/30m Trapped Dipole Antenna

SPECIFICATIONS

The TZ-RD-3W rotary dipole features include:

  • Operating bands 12/17/30M
  • Max Operating power 1 kW PEP, 500W CW continuous
  • Typical impedance 40 ohm - 75 ohm (depending on installation height)
  • Gain -0.0 to -1.0 dBd
  • Effective Gain 6.0 dBi Typical (when mounted at 1 wavelength height)
  • VSWR 1.5:1 (typical)
  • Bandwidth : All of each WARC Band
  • Total length 10.0m
  • Turning radius - 5m
  • Wind Survival 100 kmph
  • Shipping Length 1.6m, max element length 1.575m.
  • Weight 3.5 kgs (approx 8.0 lb)

PRICE:   $329.00

ANTENNA DESCRIPTION

The TZ-RD-3W is a rotary dipole antenna designed to permit operation on the 12/17/30m WARC bands. As standard the antenna is designed for the 3 WARC bands, with an optional cap hat section to enable the antenna to operate on 40m instead of 30m. If you're a bit bored with the usual HF frequencies, why not experiment with the WARC bands and learn about the different propagation on these bands. You may want to start chasing DXCC on the WARC bands for a new challenge.

PERFORMANCE CONSIDERATIONS

The antenna is full size on 12m and therefore has effectively 0 dBd gain on that band. Since trap loading is significantly along each element losses are minimised on 17m and approximately 0.25 - 0.35dB reduction in gain over a full size 17m dipole can be anticipated. On 30m the antenna is approximately 70% of full size and 0.6 - 0.8dB loss due to reduced capture area and trap losses can be expected. During real DX and local QSO conditions, the difference between this antenna and a full size mono-band antenna is almost negligible on 17m and would likely be materially no different on 30m expect under the most trying QSO conditions.

Given the antenna is significantly lighter and smaller than a beam or full sized 30m antenna, it is possible that the antenna can be mounted higher than otherwise might be the case and as such may result in better performance than what might have been achieved with a full sized antenna at a lower height.

BLOCK SIZE & MOUNTING CONSIDERATIONS

The TZ-RD-3W 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 WARC 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 5.0m (total 10m wing span).

This antenna is ideal for the amateur without much room, or dollars, or who has an XYL not keen on a big antenna and tower in the back yard. The antenna is easily accommodated by typical "scaffolding tube" aluminum or water pipe (galvanised steel tubing). If a small concentric mast is constructed and attached to the house or dwelling a simple "pipe" mast can have your TZ-RD-3W up and in the clear for under a few hundred dollars. These types of masts can usually be extended to 10 or 12m if only a small antenna is mounted at the top, giving very good DX performance. This can be a huge saving on a tower worth upwards of $5000.00, rotator, permits, town planning, etc. You'll be surprised at how well such a simple antenna can work, if mounted in the clear at height.

The TZ-RD-3W should be mounted at least 8m above the ground. Most regulations in Australia permit a mast to be erected 3m above the tallest point of the building (primarily intended for TV antennas) but this ruling can effectively be used to get your ham antenna up at least 8m. Many amateurs without much room consider vertical antennas as their only alternative, however with a turning radius of only 5m the TZ-RD-3w offers significant performance improvements over a 12/17/30m vertical when installed at heights of no more than 8m. This antenna will provide excellent DX performance to cost ratio and can be installed in all but the smallest of inner city blocks.

The TZ-RD-3W is also a fantastic antenna for portable operation. A simple aluminium mast with 3m long sleeving sections can easily be erected with some small tent pegs, half size star pickets and nylon rope guys. This will get you quickly onto the bands with a good signal. Great for a mini dxpedition to an IOTA island.

PORTABLE OR FIELD OPERATIONS AND DX-PEDITIONS

The TZ-RD-3w is also a fantastic antenna for portable operation. A simple aluminum mast with 3m long sleeving sections can easily be erected with some small tent pegs, half size star pickets and nylon rope guys. This will get you quickly onto the bands with a good signal. Great for a mini dxpedition to an IOTA island. A version of this antenna can be ordered with components no more than 1.0m long for easy shipment via air or vehicle.

ANTENNA DESIGN AND COMPONENTS

The TZ-RD-3W uses 4 coaxial traps which are not affected by rain since the traps are sealed. Acetal plastic insulating sections are used for mechanical strength and stiffness so that the antenna is subject to minimal sag. The centre sections of the antenna are 32mm O.D, tapering down to 12mm O.D. at the tips.

Stainless steel fasteners are used throughout as well as aluminium rivets for reduced corrosion. Three (3) 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-3w is supplied with all stainless steel hardware except for the boom/pole mount U bolts (optionally S/S).

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