(1) Slavonic Beam - two elements phased array with 135° phase shift (v1) and 120° phase shift (v2). This symmetric End-Fire type array consists of two dipoles and it is fed via quarter-wave transformers along with the appriopriate phased line. Current amplitudes in both drivers are the same but the phase is always shifted. That is the secret of a properly tuned phased array. Gain of said arrays is in order of 4.5 dBd to 5.2 dBd per each doublet and depends on frequency, F/B = 20dB, F/S = 50dB. Phased doublets might be stacked into the broadside array increasing the overall gain up to 8.5 dBd. Slavonic beams are the resonant antennas with the natural resonance at desired frequency where Z = 51 + j0 Ω one lambda over the very good soil. There is not any impedance matching circuit. All the arrays are made of EN AW-6060 aluminum tubes of 2" external diameter or 1" external diameter.
Fig 1. Slavonic Beam v1 - Technical drawing
Fig 2. Slavonic Beam v2 - Technical drawing
Fig 3. Slavonic Beam - radiation pattern
Fig 4. Slavonic Beam - RF voltage in feed points
(2) V-Slavonic 225 Beam - classical Vee directional antenna, 2.25 lambda per leg and the angle of 60°. Szczecin Radio uses the resonant type of Vee with the relatively low impedance in the feed-point instead of terminated, traveling wave Vee. Resonant variant of Vee is always bidirectional with the gain of 7dBd. Advantages of such Vee anntenas are that they are able to work low over the ground and have quite good gain. There is not any impedance matching circuit but the quarter-wave 75Ω transformer. V-slavonic 225 is made of pure copper wires LGY.
Fig 5. V-Slavonic 225 - radiation pattern
Fig 6. V-Slavonic 225 - impedance characteristic
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