Double Zepp Antenna

Telex Communications' new V-2 antenna is a 2-meter extended double zepp vertical consisting of two stacked 5/8-wave sections decoupled inside the antenna for complete weather-proofing. The decoupling system allows no rf on the coax feediine. The V-2 is a complete antenna that is easy to assemble and will mount on any mast up to 2" (50,8 mm) In diameter.

Two sets of 1/4-wave radials and a centered feedpoint produce an excellent radiation pat« tern that is very close to the horizon with a minimum of power loss into the sky. Radiation pattern testing was achieved on a ground-reflection range designed according to IEEE standard 149-1979; the test results of the V-2 and various competitive products are available from Teiex/Hy-Gain.

The V-2 is designed to operate from 138 MHz through 174 MHz, obtains a vswr of less than 1,5:1 at resonance, and has a 2:1 vswr bandwidth of at feast 7 MHz. The antenna's Isolation from the supporting mast is 20 dB mini* mum,

For more Information, contact Hy-Gain, a division of Telex Communicationst 9600 Aldrich Ave. So., Minneapolis MN55420. Reader Service number 486.

Double Zepp AntennaLoading Coil Antena Hygain Telex

HyGains V 2 double zepp vertical.

Scientific Dimensions' Model SDI-1150 slide mount■

HyGains V 2 double zepp vertical.

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HF5V-III from page 34

best To tune the HF5V-I1I, you simply looser: a wing-nut and slide the loading coil up or down, There are separate loading coils for 80 and 40, and adjustment ot these coils has a negligible effect on the resonance point on 20, 15, and 10. Use a waterproof marker to mark the position of the bottom of the cot! for the phone and CW segments and you'll be able to readjust the antenna without even getting near your swr meter!

The other reason i chose the HF5V-1II is the obvious care that went into its design and engineering. Butternut designed this antenna to be as efficient as possible on each band. The following theory of operation is excerpted from the instruction manual

"The HF5V-II! operates as a slightly extended quar ter-wave radiator on 15 meters, using a quarter-wave decoupling stub to isolate the upper sections of the antenna from the first quarter-wavelength of that band On 20 meters, the entire radiator is active and functions as a 3/8-wave resonant vertical having much higher radiation resistance than conventional or trapped antennas with heights of one-quarter wavelength or less. On 10 meters, the HF5V-1II operates as a 3/4-wave radiator with considerably greater efficiency than quarter wave types. On 40 and 80/ 75 meters, the appropriate resonator circuits provide the inductive reactance required for resonance in conjunction with a slight top loading effect from the 15-meter decoupling stub. The L/C ratios of the 40- and 80/75-meter resonator c ir-cuits also determine resonance on 20 and 10 meters

Because of the higher than normal 20-meter radiation resistance, the feedpoint impedance on that band is in the neighborhood of 100 Ohms in a typical installation. Therefore, a quarter-wave matching section of 75-Ohm line is used as a transformer for the 50-0hm impedance of the main transmission line. This matching section has no appreciable effect on operation on other bands."

Power rating is two kW PEP on 40 through 10 meters, and T2 kW PEP on 80 and 75 meters. Bandwidth is quite good, covering the entire 40-, 20-, 15-, and 10-meter bands and approximately 100 kHz on 80 meters. With the optional 160 meter attachment, bandwidth is considerably narrowed on 80 and 40 but still covers the entire 20-, 15-, and 10-meter bands. Wind load is 1.5 square feet overall height is 26 feet. Shipping weight comes in at 12 pounds, and DXpeditioners may be interested in the special version that allows the antenna to be packed in a relatively small package, with no change in operating c harac teristics.

Installation

Both roof and ground mounting are straightforward and uncomplicated, it takes less than two hours working at a ieisurely pace to assemble a Butternut HF5V-III The parts fit well and needed no remedial hacking or drilling. Both antennas I built required no adjustment beyond setting the 80- and 40-meter coils for the desjred portion of the band The instruction manual is very well done, with clear assembly instructions and diagrams 1 here are lots of hints on installation and ample detail on ground systems and their necessity. For the roof-mounted antenna, I used the excellent tuned radial kit that Butternut offers A system of non-resonant ra-dials resides beneath the ground-mounted antenna, with several wires in excess of 350 feet if you are interested in a vertical antenna and can't decide whether Lo mount it on the ground or on your roof, you should know that indications are that the roof-mounted antenna will be the superior performer, in any case, laying the required radial system for a ground-mounted vertical can be extremely time-consuming, I calculate that the time I spent installing the radials for my ground-mounted vertical would have easily paid the difference between a vertical and a small tribander to mount on my roof!

One has to be very cautious when comparing a vertic al to random wire or dipole antennas. Initial comparisons between a 100-foot random wire and the HF5V-IU were not particularly encouraging, I used a coax switch to flip back and forth between the antenna tuner for the random wire and the vertical, and the wire seemed to run about one S-unit higher on receive. Surprise! The low angle of radiation of the vertical made itself known when we started tuning in DX stations —DX signals were definitely stronger on the vertical!

Conclusion

The HF5V-III goes together easily and is definitely one of the best of its breed A vertical antenna rs no match for a rhombic, yagi, or quad, but for those of us with limited real estate and funding, it represents an alternative worthy of serious consideration.

For more information, contact: Butternut Electronics Co., PO Box 1411, San Marcos TX 78666.■

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