RELIABLE “THE WAVE CHANNEL” | MODEL CONSTRUCTION

The TV antenna type “wave channel” is popular even in remote rural areas. Easy to manufacture, it does not require complex tuning and matching with precisely proportional to the sizes of its elements — reflector, an active vibrator and Directors. The choice of the number of Directors of such antenna is possible within wide limits to vary the beamwidth and gain. In addition, the “wave channel” has a very small windage, which is important when installing a tall mast for DXing.

As the workpiece carrier for arrows “wave channel” is generally used thin-walled pipe of suitable diameter. Many at first it is unclear how to drill it through-holes for fastening of Directors, an active vibrator and the reflector, so that the axis of all the holes lying in the same plane. You can use the following method.

At the base of the auxiliary boom is drilled horizontal through hole in which is inserted a short section of rod or tube and towards the annular rubber bands or a few turns of adhesive tape are fixed on the building level two linings in order to avoid bias in contact with the bearing arrow. The minimum thickness of the linings is determined as the difference between the radii of the carrier boom and auxiliary parting bars or tubes.

Then this piece set of horizontal accuracy check level — pegging vertically drilled through holes for fastening of Directors, an active vibrator and the reflector. It is a pity that the high efficiency of this method is guaranteed only when using drill press or hand drill with a special vertical guide.

It is difficult to achieve reliable fastening of Directors, an active vibrator and reflector due to only one tight they fit in the holes of the carrier boom. When the antenna swings in the wind this mount quickly becomes loose. Often diagrammable elements (especially in the case of their vertical location) are excluded.

To avoid this, we recommend the strengthening of a tight fit of Directors, an active vibrator and reflector in the holes with epoxy glue.

More convenient as a carrier boom “wave” channel in the UHF range, use the cut dural area. In this simplified not only commit themselves diagrammatic elements of the antenna and its mount to the mast.

Manufacturer of loop (slavnogo) active vibrator fraught with the greatest difficulties. To bend the element antenna is best on a special mandrel. In its absence you can use fixed tube, the external diameter of which is equal to the width of the loop of the vibrator. Preferably to the free ends of the loop to screw the insulation Board (for example, of 2-mm glass fiber). Thereto by means of brackets you can attach the end of the feeder (cable reduction), as well as matching-balun loop. The latter is, if the feeder is not used 300-Ohm symmetrical tape CAT, and any of the common “coaxial”, whose resistance at the natural frequency is 75-100 Ohms.

The method of performing the mounting holes in the carrier boom in the manufacture mnogosloinoi antenna type

The method for performing the mounting holes in the carrier boom in the manufacture mnogosloinoi antenna type “wave channel”:

1 support rod; 2 — building level; 3 — retaining ring 4 —• a lining; 5 — a bearing arrow; 6 — namereny future centre mounting holes (number according to the number of antenna elements, including the active vibrator)

With the lack of fees is inevitable when installing and configuring the antenna mechanical loads are applied to the Central veins of the cord is reduce and the matching-balun loop that threatens their oblamyvanii the combination with a train. In favor of the installation charges also show other important factors. Here and the possibility of replacing the soldering more convenient bolted, and reaching the location of the matching loop strictly in the plane of the active vibrator, which is a necessary condition for effective operation of the antenna.

Attach the loop to the carrier-bolt is best bolt with nut. And this should be done in such a way to active the vibrator did not cover the arrow. Otherwise, for removing plume (breakage of the feeder or matching-balun loop), it will be necessary to temporarily release the antenna or the reflector, or from all Directors.

Coaxial cable with a symmetrical active vibrator atenna:

1 — coaxial cable reduce; 2 — fixing bracket (3). 3 — the active vibrator; 4 — insulation Board (glass fiber s2); 5 — bolt (5 PCs); 6 — matching-balun loop (a segment of coaxial cable)

In the manufacture of “wave channel” is recommended to place an active vibrator so that the matching-balun loop was over the boom and over the cable to reduce. If, after such Assembly to put on the matching loop plastic bag and attach it to the Board with tape, it is possible to reliably protect this important site from moisture.

The orientation of the antenna on the transmitting television station normally perform together. However, there is a fairly simple and effective way to cope with this alone. A necessary condition — the antenna design should allow for horizontal rotation of the boom on the mast. Will require a spring, a coil of fishing line or twine.

With a section of fishing line and a light spring turn the antenna at first, so that the direction of the arrows in the horizontal plane by 20-30°, “did not reach” to the intended direction for the television station. On the opposite side should also be clipped line. It should serve as a leash, the end of which with the least possible number of bends you put in the room with the TV. The course the line should be free. Choosing a bottom line for yourself, you can change the angle of rotation of the antenna about 60°, depending on the stiffness of the springs and the points of attachment of the fishing line to the arrow, while observing the TV screen. Grazing of leash spring “counterweight” will begin to pick up the slack and return the antenna to its original position.

Method of orientation of the antenna on the transmitting television station:

1 — mast; 2 — antenna; 3 — “versus” (a segment of fishing line with a spring); 4 — the leash (line)

It is usually difficult for the eye to determine the position of the antenna with the best reception, especially for designs with wide beamwidth. But easier, if you focus on transmitting the television station used the snap.

In particular, when the free lower end-of the leash provide a label moving along any uniform scale, for example ruler. On the scale, make notches in the two end positions of the label corresponding to the limit angles of rotation of the antenna in which there is disruption of the television image. The exact direction of the television center corresponds to the position of the label relative to both the ticks on the scale.

The lower end of the fishing line is fixed in this position and move to the antenna, performing a final rigid fixation of its arrows in the direction held by the leash and “counterbalance”, the spring, which is preferably positioned in the vicinity of the point of attachment to the support.

Yu. A. Pozdnyakov

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