WOODEN ANTENNA…

WOODEN... ANTENNAThe ham-hams is well known that, to ensure reliable connection in addition high-sensitivity receiver and a powerful transmitter is needed and a well-designed antenna. There are many types of antennas, however, have to limit ourselves to just two or three. And one of them often becomes a quarter-wave vertical pin or, more precisely, its improved version, which in radio is called the Ground Plane.

I’m not going to tell the readers about the configuration of the antenna — about it in detail is described in specialized publications. The problem I have is to acquaint the hams with the design of such antenna.
 
As known, the base whip antenna is solid metal or composite bar or, even better, the dural tube is a length of a quarter wavelengths used. For the most popular twenty-meter short-wave range operating (electrical) length of pin is exactly 5 meters.
 
However, when I started to do such an antenna, get the duralumin pipe with a diameter of 40 — 50 mm and a length of about five meters I could not.
The task seemed hopeless, but helped me… normal food aluminum foil, which is sold in hardware stores rolls of a width of 0.2 — 0.3 m; the length of such ultrafine metal strip of about 20 meters.
 
Of course, rolling out of foil pipe length of 5 meters is possible, but with excellent electrical conductivity, its strength and stiffness will actually be zero. But not necessarily the functions and power conductive parts of the antenna to hold a single element of the design. Indeed, the electrical conductivity of the pin may be able to provide the finest aluminum foil, and its strength and rigidity — wooden rod with a length of 5.5 m, covered with a layer of fiberglass.
 
Design of a quarter wave whip antenna type Ground Plane
 
Design quarter-wave whip antenna type Ground Plane:
 
1—an antenna pole; 2—”umbrella” (top 9-liter bottle); 3—connecting clamp (made of anodized aluminum, strip 15×3), 4—a Central pipe of the base (steel, pipe 60×3, L = 270); 5—clip (steel, wire Ø5); 6—coaxial antenna cable; 7—connecting wire balances (antenna cord Ø4); 8—pillar base (steel, pipe 30x40x2,5); 9—sole (steel, sheet s4); 10—counterweight (the antenna cord Ø4); 11—screw-tapping screw (Ø6×80); 12 — porcelain insulator; 13—screw a hook (Ø5×50 (steel)

 
First I picked up is smooth, without knots and ROE bar with a length of 5.5 m and a cross section of 50 x 50 mm and made a wooden truncated cone with a large diameter of 50 mm and smaller — 20 mm. Next, the resulting wood pin with epoxy glued a strip of fiberglass with a length of 5.5 m and a width of 0.2 m. before the resin starts to “grab”, spread on the floor of a prepared strip of polyethylene with a length of 5.7 m and a width of 0.3 m, and on top of it and laid foil with a length of exactly 5 m and then on top of the foil placed covered with fiberglass pin and carefully wrapped it with metal. The lower part of the pin on a plot with a 0.5 m foil not papered. Well, where ended aluminum part, defended foil from contact “epoxy” with several wraps of vinyl electrical tape in the future in this place was installed dural clamp for electrical connection of the antenna coaxial antenna cable.
 
To ensure a tight fit of the foil to the fiberglass and the wood, preformal to the antenna strip of polyethylene film and tightly opisoval her wound with the tape-adhesive tape. The next day, cut the tape and easily remove it together with polyethylene (he did not adhesive with epoxy glue).
 
Thus, the main part of the antenna is almost ready. Were only on the bottom not covered by the foil end of the pin to stick a few layers of fiberglass epoxy resin, bringing the diameter of this part of the antenna up to 64 mm. Fiberglass and epoxy resin — are good insulators, and the presence of fiberglass belt at the bottom of the pin safely isolates it from the metal base of the antenna.
 
The base of the antenna is welded, it consists of a Central pipe with a diameter of 70×3 mm (inner diameter is 64 mm, which will give the opportunity to insert a pin in the base) and four pillars of steel pipes of rectangular section 30x40x2,5 mm. To the last four welded feet (steel strip with a thickness of 4 mm) and four staples from wire with a diameter of 5 mm.
Connecting the Central conductor of the coaxial antenna cable with aluminum foil is made with aluminum clamp, covering the lower foil portion of the pin by tightening the bolt of the clamp should enclose the copper mounting lugs, to which is soldered the metal core of the antenna cable.
 
For efficient operation of quarter-wave probe-vibrator, you need to provide the conditions for a kind of electric mirror reflection of this antenna, which is achieved by radiating from the antenna pin cords (balances).
 
The electrical length of each quarter is also emitted (or received) wavelengths — in our case this is 5 meters. In the described antenna four of them, although the number of cords-balances can be increased. Each of them is isolated from the supports of the antenna and from the roof by a pair of insulators (by the way, in our time, to get a classic insulators is not easy, but good self-made insulators out of the bottle cut from a plastic bottle). In the Central part of the counterweights are connected through a circular conductor, with the latter connected by soldering the braid of coaxial antenna cable.
 
The sequence of manufacturing the antenna pin
 
The sequence of manufacturing the antenna pin:
 
1—manufacture of wood tapered billet antenna pin; 2 — pasting blanks fiberglass; 3 — pin covering the antenna with aluminum foil; 4—preferowane separator (polyethylene film); 5—crimping the antenna pin adhesive tape-Scotch

 
General view of the antenna type Ground Plane
 
General view of the antenna type Ground Plane
 
Important detail antenna is an “umbrella” covering the Central tube of the antenna base. To install it you need to take a closer look — moisture on the lower part of the pin could impair the Ground Plane. The easiest way to do this “umbrella” of the 9-liter plastic bottle (they sell drinking water).
 
As mentioned above, the outward simplicity of the antenna type Ground Plane setup its quite time consuming. However, on the Internet you will be able to find at least a dozen methods of its settings, including with application of simple devices.
 
And the last one. Using the technique of creating a “wooden” rod antenna, is not too difficult to do the same “wooden” elements for the directional antenna of type “wave channel”, as well as various TV antennas.

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