1º the reframing
Purchase of materials (that already are very expensive), etc
In the image is part of the facilities of the repeater of Mijas (Malaga).
We obtain a more real budget
2º Uso of coaxial cable
Although already we have seen coaxial cables, is necessary to emphasize that the radio installations, are used powers that make necessary the use of a special type of these cables, that we will see now.
The coaxial cable nowadays is used in radio equipment to communicate the equipment of R.F power with the antennas. Its use is due to the smaller losses compared with other cables.
Facility in the use of connectors
The coaxial cable is formed by two concentric drivers. One interior (called “alive”) and another outside, formed by “enmeshes almost always”.
The alive driver usually is a single massive thread or several twisted threads. The outside, aside from enmeshes, usually has an aluminum lamina or receives, increasing its shield.
Finally, the insulator is formed normally of by a plastic (polythene).
In the image superior we will see some cable types who we have in the market, whereas clause which usually they are used in nomenclatures of type 1/4” (a quarter of inch), making reference approximately to the diameter of the cable. In the figure superior is the constitution of the different cable groups, where the alive one can be indented, smooth or helical. The driver more using usually is copper, although by price and/or weight, usually he is replaced by aluminum
a) Search in Internet 3 cable types used in RF and to make a table with the following data: Measures of the conductive external intern and, impedance of the cable, attenuation in three frequencies to choose
b) How it varies the attenuation in function to the frequency?
1º Standard Connector (SC).
Created by Nippon Telegraph and telephone, the FC has a rule of size ceramics 2,5 mm with spiral subjection. Good in applications with in surroundings of high vibrations, given the fixation that confers the spiral to him.
APC (physical Angled contact), in this case, to increase the reflection until the -60 db, polishes the rule in convex angle of 8º
To show/To hide Polished to Connectors Fiber
Rule to remember the systems of polished
As introduction and making a little history, in 1936, while some were dedicated to kill themselves by their ideals (home of the Spanish civil war), others invented one of the machines that the society has revolutionized. We speak of the PC, whose inventor You honor Zuse, gave name him as Z1.
Good then of this history, we are going to have our rule, because it is spoken of two things, the PC and years 30. Phenomenon, because PC
it is the first connector (Physical contact), that in addition, db has a reflection of -30 (decade of the discovery of the PC).
From here, we increased to decade and improvements. If he is better is Super and we increased 10 db, therefore we have the SPC with -40db.
Soon if he is still better, he is a Extreme one, obtaining a UPC the -50 dB.
In order to finish, still we must already give to an angle to the rule, obtaining our APC with -60 Db
If you learn this, it will be easier to remember it. The protection of the antennas is fundamental against the bad weathers.
With the previous thing and considering that the fiber can be monoway or multiway, a color code settles down that will give to information on the fiber and the polished one us. We have: Green
- > indicates to Us that the rule is of type APC Black or
Red - > Polished PC, SPC Or UPC
Azul-> indicates to Us that the fiber is monoway
Beige-> In this case, the fiber is multiway
Yet this, we are going to make an exercise.
In the following figure, to specify the characteristics of the connectors that are in the image.
To make the exercise and to verify results at the end of this page.
4º Closet for equipment (Rack)
These iron components, made normally, usually have a measurement standard for the equipment that is going to lodge.
In our photo we showed one of 19 “, that we used to install switch, path panel, feeding strips, etc.
If the thermal load is elevated, ventilators settle (the one of the photo does not take it). In addition it is necessary to locate the elements that more generate heat in the part superior.
In all installation a free space for new extensions is due to leave, that will have to be calculated on the basis of which we have already installed.
5º. Earth kit:
In order to avoid the electrical unloading of outsourcing (mainly of rays), some are placed clips, that made in plastic contain enmeshes of copper that makes contact with the external driver of the cable. In order to avoid oxidations, it is protected with vulcanizante tape.
One by each curve is placed that has the coaxial cable of slope. When the section is very long, we put a unloading clip each 12 meters. If the slope is not very long, one and another one is placed at the outset in the end.
As its word indicates, they are perforations that have partitions and walls so that the cables can leave the tower.
We must have the precaution to maintain sealed them (we avoided the water entrance). In addition, it must have a negative inclination from the interior to the outside, to avoid that the water pass by the cable towards the interior