| ¡¡ |
 |
 |
 |
 |
 |
 |
 |
 |
| ¡¡ |
 |
|
|
| The span of the coaxial cable, which is
the most complex and easiest to be damaged in fact, is a link easily
ignored in CATV construction. We will introduce the span of familiar
self-bearing coaxial cable and round coaxial cable below 1 The setting line of cable In order not to be damaged and shape distortion during the line setting course of cables, make sure to use cable reel to set line. And the cable without cable reel should make a drawing drum itself. Furthermore, set drawing ring at the turning site (when the angle is below 90 degree) of the cable drawing. It must not put the wreathe packaged cable to the ground to draw core thread or peel off the skin when to set line 2The span of cable Make the dragline(wire rope) go through the ring in succession and drag at the top of the dragline. After the dragline whole going through the span region to drag at the terminal or span the cable when the proper length of the dragline goes through the pulley yoke orderly. When dragging by human force, care must be taken that the drawing tension and speed should be kept as equal as possible when dragging. When dragging, it should be equipped with construction contact signal persons and inspection persons, etc. to connect with by using signals regularity at the line delivered spot and proper region in the middle (especially the turning pole, road, spanning railway site and other sites having obstacles) and the drag spot so as to avoid the disadvantage emergence when to drag. It always uses 20m/min speed when to drag and should go on smoothly. More attention should be paid to when dragged by human force. Besides the signal contact persons, at the cable reel delivered site, it should be equipped with operators to answer for adjusting the rotating of the whole cable reel and properly drag so that the biggish loosen (sagging) phenomenon can be avoided when the cable being dragged among the knightheads. It should be equipped with signal inspection persons to keep safety at the road transversal spanning site where is more passerby and cars and other sites where will worry about the obstacles when to span. When the front end of the cable reaches the terminal pole of the spanning region and drags to the length (approximate above 12m) necessary remained, the ring should be unloaded and fix the cable to the knighthead. Certainly, the length that cable remained should be taken into account when the machines, such as amplifiers and so on are installed. After fixing the terminal pole, hang the cable on the knighthead orderly starting from the nearest knighthead of the terminal pole. 3 The adjustment of the cable sag The sag is the vertical distance between the highest point and the lowest point of one span. According to the conditions, such as cable outer diameter (including the outer diameter of backup line), weight of cable, span, intension of backup line and the temperature when to span, the value of cable sag is different. So choosing appropriate sag should base on the cable data. The sag of summer is not more than 50cm, sag of winter is not more than 30cm. Whether the sag complies with demand or not, the manpower inspection method can be used: hang the rope on the messenger wire when the air temperature is 20¡æ, drag down with pull of 60kg, when the droop is less than 50cm, the sag is qualified. 4 The fixation method of cable at the knighthead £¨1£© The fixation of terminal pole. Adopt the messenger wire to fix connecting with metal (or the line nip), or C-shaped, plug-in metalwork for the self-bearing cable that the backup line is single. Adopt free staple bolt and thimble wrapping stub for the round coaxial cable that the backup line is steel strand. £¨2£© Two-way fixation to the straight line. £¨3£© It should make the cable go across the inner side of knighthead when turning. Under the inner angle exceeding 170 degree, it should obey the straight line method to hang, but when the inner angle is less than 170 degree, it should refer to the drawing 1 to fix at double side.  5The gallows method under several special circumstances. 5.1The cable hang of the aslope The gallows metalwork is installed from the holding side to the horizontal orientation under general circumstance. But the aslope should equip with the slope of the line. When the inner angle of turning pole is 150 degree and the pole with angle of depression and angle of altitude of more than 15 degree, it should be tensely fixed in two-way. 5.2Projecting hang Due to the billboard, trees and eaves baffling the cable directly installing on the knighthead or the cable and transformer or other lines spanning on the same pole, it should keep certain distance with them. 5.3The turning among the poles Install the messenger wire pole offshoot metalwork on the turning top and the turning site of the backup lines among poles so as to make horizontal dragline wrap the stub and go along with connection. 6The support and binding of cable. 6.1The support of cable The support of round coaxial cable can adopt cable hook or make hook by self. Generally, the backbone adopts the cable hook or use the hook made self. 6.2The binding of cable 6.2.1The binding of round coaxial cable The cable of the round coaxial cable at the two ends where the amplifier and the field offshoot distributor are installed should be binding fixed. The cable at the aslope and the turning site among poles should be bound. 6.2.2The binding of self-bearing coaxial cable The self-bearing coaxial cable is bound where the self-bearing line is separated from the cable. To protect from separating using ethylene tape to wrap the whole self-bearing line and the cable more than three layers and also can use thin tie wire to wrap it over three circles to fasten. |
|
ADD£ºZhulin street, Linan Hangzhou Zhejiang Post£º311300 TEL£º0571-63721211 FAX£º0571-63720835 Mobile:13706711666 Contact£ºMr.Shi Miss Yao E-mail£ºsanji@la.hz.zj.cn URL£ºhttp://www.sanjicable.com |
