The Delta antenna for 144 MHz
Connect the power cable with wave resistance of 75 or 50 Ohms is via g-matching device. Figure 1 shows the mechanical construction of one element of the antenna. Horizontal element l1 better be made of copper or aluminum wire with a diameter of 2.5..5 mm. Vertical elements l2 are made of tubes with a diameter of 10 mm or bimetal rod. The ends of these rods are inserted perpendicular to each other in the holes in the carrier traverse, which has a rectangular (h mm) or round cross-section. This design is rather hard and at the same time allows you to easily change the distance of the vertical elements in the antenna tuning.
Design of a single element Delta antenna
Design a two-element Delta-antenna
Design of three-element Delta-antenna
Design five-Delta antenna
Even better results can be achieved using the double Delta antenna. Variant a three-element Delta-antenna shown in Fig.5. This antenna gives a gain of up to 10...11 dB. Singleton double Delta antenna has a gain of 3 to 4 dB. Two-element double-Delta antenna with the Director and reflector gives increased from 8 to 9 dB.
The design of the three element twin Delta antenna
Author: W. FAULHABER - Y28RL/Y38ZL, Translated from German by N. Bolshakova, RA3TOX; Publication: N. Bolshakov, rf.atnn.ru