In activitatea de radioamator, antenele pentru benzile de 14,21 si 28 MHz, in special cele directionale, solicita o atentie deosebita. Astfel, dipolul pentru banda de 14 MHz are lungimea de 10 m, ajungind la 5 m pentru banda de 28 MHz. Marimea antenelor directionale cu elemente pasive reprezinta 0,25 pina la 0,3 λ pentru antenele cu trei elemente.
Necesitatea asigurarii unei rezistente mecanice suficiente la curentii de aer mai mult sau mai putin violenti ne obliga sa fixam elementele antenei pe un schelet de lemn prin intermediul unor izolatoare robuste.
Pentru realizarea elementelor antenei folosim in mod frecvent metalul, si anume, tuburi de duraluminiu, care este materialul cel mai rigid. Totodata, pentru a evita curbarea elementelor sub greutatea capetelor, vom folosi o „solutie telescopica”, plecind de la tuburi de circa 30 mm in centrul elementelor si continuind prin introducerea telescopica de segmente succesive, cu diametrul din ce in ce mai mic, pina la 10—15 mm la extremitati.
Ultimele segmente se realizeaza culisante, pentru a permite acordul precis al elementelor.
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