Antenna for field day
Often only complain about the lack of necessary materials for the manufacture of antennas. How do you solve the problem hams Kolomna (RK3DZD)? They, for example, in the manufacture of multi-element УSW antennas use materials, store-bought or literally lying under their feet.
For a beam antenna in the sporting goods store purchased metal hoops ("hula-hoops"), those who love to twist the girls (and not only they). In as active and passive elements are aluminum conductors power cable (trim can always be found on any construction site, the dump...).
"Hula hoops" cut with a hacksaw, opened the internal cavity of the fill pipe sand and C at the fire, straightened. Power cord cut into pieces the length is a little over one meter, cut off the outer insulation and remove the wires. With they also cut off the insulation, but not completely - leaving in the middle of a small areas with a length of 30 to 40 mm (Fig. 1).
From these blanks we did the nine - and shestnadcatiletnie antenna design F9FT. They were provided by the participants in the competition "Field day".
Traverse the antenna was assembled from pipe segments received after the cut "hulahoop", with inserts (If the antenna is designed to work in the specific competitions and just a few days, then the insert can be made of of the tree). After Assembly it traverses mark places of fastening elements. For this is to traverse through rings of duct tape fix the painting metal measuring tapes. Blade attached along the entire length with spacing of 30 cm Then nutriway point for future openings in accordance with the calculations of this scheme the antennas. The drill diameter is selected so (taking into account the diameter of the insulation of the conductors), the antenna elements were inserted into the prepared hole (Fig. 1) with considerable effort.
In Fig. 2 shows a diagram of a variant webcam Central software band antenna 144 MHz.
The active element is a vibrator made of copper tubes. Its design represented in Fig. 3.
A feeder that feeds the antenna plug to the vibrator via coaxial connector, soldered directly to the driven element.
Antenna, intended for the carriage, should be easy to understand. Webcam Central software antenna manufactured according to the described technology, a handle on two parts, and shestnadcatiletnie - three.
As the mast under field conditions is quite possible to use dry pine, and if it would not close, the mast will have to build from the captured with a pre-cut water pipes.
If you want to work FM and polarization vertical antenna, it is better not attach it directly to a metal mast, and to make the side using "hands" of a length of λ/2.
Author: I. Grigoriev