Antena quad pe care am descris-o in amanuntime la capitolul anterior poate fi folosita cu acelasi succes si in banda de 144 MHz. Ne vom opri la antena quad cu reflector (fig. 259). In practica, cele doua cadre sint de aceleasi dimensiuni, elementul reflector fiind alungit printr-o linie paralela scurtcircuitata la capat. Prevazind un reglaj al puntii de scurtcircuitare, vom putea preciza lungimea optima a liniei. Pentru banda de 144 MHz perimetrul cadrului este de 2,10 m, distanta intre vibrator si reflector 0,26 m, lungimea aproximativa a liniei suplimentare a reflectorului 0,10 m, distanta dintre conductoarele liniei 3 cm. Dupa determinarea pozitiei optime a puntii de scurtcircuitare a liniei, pentru un cistig maxim de cimp si un raport fata-spate de circa 25 dB, aceasta se cositoreste Ia conductoarele liniei, iar capetele de linie ramase se taie.
Alimentarea corecta trebuie facuta printr-o linie simetrica cu impedanta de 75 Ω sau printr-un cablu coaxial de aceeasi impedanta, dar folosind un dispozitiv de simetrizare. Conectarea cablului coaxial nesimetric fara dispozitiv face ca o parte destul de importanta din energie sa fie radiata de cablu, cistigul de cimp se reduce, ca si raportul fata-spate.
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