The DX-88 is a very good vertical antenna by Hy-Gain, which covers the 80, 40, 30, 20, 17, 15, 12 and 10 meter bands. With an optional kit the DX-88 can also work on 160 meters. The antenna is self supporting and comes with stainless steel hardware making it quite robust in windy conditions. Like any other vertical antenna, the DX-88 performs best with a ground radial system.
|Transmit||80-10 meter Amateur Bands|
|Receive||3-30 MHz, tunable|
|Input impedance||50 ohms|
|SWR at resonnance||Less than 1.5:1 using recommended radial system|
|Max Power||1500W PEP, 700W avg, 250W on 30, 500W on 17|
|Max height||7.54 m|
|Weight, net||8.2 kg|
|Mast diameter||38-41 mm|
|Wind survival, unguyed||121 km/h|
The DX-88 vertical antenna utilizes its entire length for radiation on both 80 and 40 meters. It resonates on each of these two bands with the aid of a tuned circuit near the base which looks inductive in the 3.5 – 4.0 MHz band and capacitive in the 7.0 – 7.3 MHz band. Adjustable piston capacitors set the resonance of this tuned circuit, which affects the amount of inductance and capacitance, and the resulting antenna resonances within each band. The remaining bands are obtained by using low-loss, high-Q tunable traps to isolate one-quarter wavelength sections along the radiator. One-quarter wavelength sections always produce low-angle radiation patterns without high-angle lobes. The distances between the traps are fixed and the traps themselves are tuneable, except for the 30 meter band. This allows the antenna to operate on the new WARC bands of 12 and 17 meters as well as the older 10, 15, and 20 meter bands. This also allows the DX-88 to resonate very close to the international SWL bands, with the proper adjustment of each trap.
The antenna consists of many bits and pieces, which have to be assembled. Great fun and a good project in the summer time. The advantage of this is that you can buy the individual parts piecewise from Hy-Gain if you should need to replace any of them. I only had to replace the base element so far, but you never know.
The manual seems quite good with nice drawings illustrating how to assemble the antenna step by step. I never had to fully assemble the antenna myself, but I might just do that once in order to see how easy it is.
There is also good description of how the resonant elements have to be tuned for the different band segments and there are even some quick-settings for CW, SSB and SWL hams. The graphs showing the tuning parameters as function of centre frequency could, however, be of a little better quality.
The best concerning the manual is that it is available on-line on the Hy-Gain web site.
On the Air
This is definitely one of the best vertical antennas I have ever used. Ok, I can only compare with a roof mounted 12AVQ, which was rather lousy, and a HF6V from Butternut, but with this antenna mounted on the ground and supplied with a radial kit I have had many great DX QSO using 100 Watts only. I can even get through in pile-ups rather quickly.
Considering that I have only paid approximately 150 Euros for it, it has definitely been a good investment.