Compact two-element Sigma-Yagi
For the production of small two-element Sigma-Yagi proposed by Peter Schmidt, DL9JFT need a few meters of steel pipe, personaly cable, antenna cord and four sticks from steklovary. As can be seen from Fig.1 (dimensions shown are for the 20-foot range in square brackets - to 10-meter range, and in a round - CBS) carrier cross member made from steel pipe Pg21 with a diameter of 28 mm.
At the ends of the yoke are welded two transverse steel pipe Pg11 with a diameter of 19 mm. In these cross-beams are skipped sticks from steklovary or another material having good insulating properties and can withstand high mechanical loads. This construction forms a fastening system for sigmaaldrich of the vibrator and the reflector, made from antenna cord and stretched using Baranovich of cables with a diameter of 3 mm (see figure). Adjusting the antenna for minimum SWR is achieved by changing the length of the leaf vibrator. For this purpose the ends of the vibrator length of about 200 mm left hanging freely as shown in the figure.
The author of such antennas on the ranges of 20 m and SV was achieved minimum SWR of 1.2. The antenna 20-meter band was located in the attic with the orientation of the primary radiation to the East, the author received good reports from LA, P29, JA
Author: Peter Schmidt, DL9JFT; Publication: N. Bolshakov, rf.atnn.ru