怎樣正(zheng)確選用射(she)頻電(dian)纜

一，射頻(pin)(pin)(pin)電纜(lan)(lan)(lan)也叫同軸電纜(lan)(lan)(lan)，是由互相同軸的(de)內導體(ti)、外導體(ti)以及(ji)(ji)支撐(cheng)內外導體(ti)的(de)介質組成的(de)。在無線電通(tong)訊、廣播電視(shi)的(de)射頻(pin)(pin)(pin)傳(chuan)(chuan)輸中，射頻(pin)(pin)(pin)電纜(lan)(lan)(lan)是重要的(de)量備。如果(guo)選用不(bu)當，不(bu)僅會造成浪費，增加投(tou)資成本(ben)，也會使系(xi)統工作(zuo)時不(bu)穩定，引(yin)發(fa)故障，造成設備損(sun)壞。為了(le)正確地選用射頻(pin)(pin)(pin)電纜(lan)(lan)(lan)，就需要學習了(le)解一(yi)些有(you)關(guan)電纜(lan)(lan)(lan)的(de)特(te)性(xing)(xing)參數(shu)和類型(xing)。射頻(pin)(pin)(pin)電纜(lan)(lan)(lan)的(de)特(te)性(xing)(xing)包(bao)括有(you)電器性(xing)(xing)能和機械性(xing)(xing)能，電器性(xing)(xing)能包(bao)括有(you)特(te)性(xing)(xing)阻抗、傳(chuan)(chuan)輸損(sun)耗(hao)及(ji)(ji)其頻(pin)(pin)(pin)率特(te)性(xing)(xing)、溫度特(te)性(xing)(xing)、屏蔽(bi)特(te)性(xing)(xing)、額(e)定功率、最(zui)大耐壓機械性(xing)(xing)能包(bao)括有(you)最(zui)小彎曲半徑(jing)、單位長(chang)度的(de)重量、容許最(zui)大的(de)拉力(li)、以及(ji)(ji)電纜(lan)(lan)(lan)的(de)老化特(te)性(xing)(xing)和一(yi)致(zhi)性(xing)(xing)。

二，在實際選用(yong)(yong)(yong)射(she)頻電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)的(de)時候，應(ying)考(kao)慮(lv)到它的(de)特(te)性(xing)阻(zu)抗、額(e)定功率(lv)、衰減量和(he)能承受的(de)最高工作電(dian)(dian)(dian)(dian)(dian)(dian)壓。在無線電(dian)(dian)(dian)(dian)(dian)(dian)通(tong)訊(xun)、廣播電(dian)(dian)(dian)(dian)(dian)(dian)視的(de)射(she)頻傳輸中，要結(jie)合(he)發(fa)射(she)機輸出(chu)的(de)射(she)頻阻(zu)抗，輸出(chu)功率(lv)、和(he)可(ke)能達到的(de)峰值電(dian)(dian)(dian)(dian)(dian)(dian)壓，并且留下一(yi)(yi)定的(de)余量，結(jie)合(he)使(shi)用(yong)(yong)(yong)的(de)環境條件，選擇合(he)適的(de)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)。需要注意的(de)是，在使(shi)用(yong)(yong)(yong)射(she)頻電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)時，一(yi)(yi)定要匹配以(yi)相同特(te)性(xing)阻(zu)抗的(de)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)插頭、電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)插座、和(he)同軸轉換(huan)開關，不能混用(yong)(yong)(yong)，以(yi)免引起較大的(de)電(dian)(dian)(dian)(dian)(dian)(dian)波反射(she)，在電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)內形(xing)成駐波。

三，射頻電(dian)(dian)(dian)纜(lan)(lan)用于中(zhong)波(bo)(bo)時，因(yin)(yin)其工作頻率低(di)，損耗小，因(yin)(yin)而(er)原來在(zai)電(dian)(dian)(dian)視(shi)上用于的(de)射頻電(dian)(dian)(dian)纜(lan)(lan)，在(zai)中(zhong)波(bo)(bo)傳輸系(xi)統中(zhong)，可以用于50KW的(de)系(xi)統中(zhong)，但(dan)是電(dian)(dian)(dian)纜(lan)(lan)內通(tong)過(guo)的(de)電(dian)(dian)(dian)流會遠(yuan)大于米波(bo)(bo)段的(de)電(dian)(dian)(dian)視(shi)系(xi)統，所(suo)以要(yao)保證電(dian)(dian)(dian)纜(lan)(lan)頭(tou)和電(dian)(dian)(dian)纜(lan)(lan)插座間接觸良好，否則會因(yin)(yin)過(guo)熱引發(fa)故障。