Lucreaza pe frecventa de 435 MHz (fig. 260). Se deosebeste de antenele obisnuite prin modul de adaptare a cablului coaxial de alimentare la vibratorul antenei, respectiv adaptarea in Y modificata.
Vibratorul-radiant este confectionat dintr-o teava de cupru lunga de 325 mm, cu diametrul 6 mm. Din acelasi material se confectioneaza si reflectorul, lung de 340 mm. Directoarele au toate aceeasi lungime, 300 mm, si se confectioneaza din vergele de duraluminiu cu diametrul 4 mm. Traversa purtatoare, avind o lungime de aproape 3 m, se confectioneaza din teava de duraluminiu sau otel, cu diametrul 10 mm, in care se perforeaza orificii pentru fixarea elementelor antenei. Toate celelalte dimensiuni sint indicate in fig. 260.Fata de frecventa de 435 MHz lungimea antenei este de 4,35λ si coeficientul de amplificare 15,2 dB. Cablul coaxial de alimentare va avea impedanta caracteristica de 52 sau 60Ω, deoarece in sistemul de adaptare este prevazut un condensator a carui capacitate poate varia de la 1 pina la 8 pF, prin aceasta realizindu-se adaptarea la cablul respectiv.
Invelisul exterior de protectie a cablului coaxial se indeparteaza pe o lungime de 15 mm de la capat si masa metalica a cablului se infasoara cu citeva spire din conductor de cupru argintat cu diametrul 1 mm, care se conecteaza la teava purtatoare a antenei. Conductorul central al cablului se racordeaza la condensator. Toate aceste racordari trebuie bine cositorite si protejate contra actiunii umezelii.
This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Cookie settingsACCEPT
Privacy & Cookies Policy
Privacy Overview
This website uses cookies to improve your experience while you navigate through the website. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may have an effect on your browsing experience.
Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.