Information Technology      Technician in Facilities of Telecommunications About



repeater of mijasElements in Radio installations

1º the reframing

  1.  He is not the same to make a budget of a work on references given by a client, who to in situ verify the real situation of work. This happens in a simple budget of plumbing and, still more, in a project where many external factors take part as:
  2. Situation of the installation
  3. Access to the place

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

From the above, that activity of reframing must take shelter in a document that includes each one of the vital data, as they are the data of the work, date, state of I accede (if there are good ways, necessary type of necessary vehicle, etc), permissions, listing of all the materials necessary (cables, equipment, antennas, etc) flat, existing alarm, security, etc the equipment that we must take to make the reframing consists of tape measure, measuring laser, GPS, compass, keys from access to each place of the property and of closets, etc.


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.

  1. The characteristics of these cables can be summarized in:
  2. Resistance outdoors
  3. Easy handling in the facilities
  4. Immunity to the noise
  5. Relative attenuation in high frequencies
helical coaxial cable

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?

c) How it varies the attenuation on the basis of the dimensions of the cable?

3º. Optical fiber. Connectors
  1. Before entering its description, we must consider 3 basic elements in the connectors
  2. The fiber type, if it is monoway or multiway
  3. The rule, that is the material that in its interior protects the fiber and serves as interface between the fiber and the receiver (the female connector). It is the “plastiquito” that it leaves the connector.
The color of the connector, that makes reference to polished of the rule and the type of fiber. We have green for polished APC (reflection of -60 Db), blue for monoway, ivory for polished red or black multiway and for with reflection of -30 to -50 Db.

 At first, the companies of Telecommunications developed to diverse fiber connectors fulfilling Fiber Optic Connector Intermateability Standars (FOCIS). A few prevailed over the rest, that we happened to comment 

Standard Connector (SC)Standard Connector (SC).  

Developed in the 80 by the company Japonesa Nippon Telegraph and telephone. They have a loss of insertion of 0,25 dB and are described to support 1000 cycles of connection-disconnection. It can more be the used connector of all Lucent Connector (LC) Lucent Connector( LC


This connector was created by the Lucent Technologies company, at present being very used in applications of fiber monoway, due to a very simple connection. In these connectors LC we have some typical losses of insertion of 0.10dB. So large reduced his it allows easily to integrate it in the electronics destined to telecommunications. Connector of straight end or Straight Tip (ST).Connector of straight end or Straight Tip(ST


Created by the company of teleco AT&T, 0.25dB of loss of insertion has some. The fiber is in favor subject of a rule of 2,5 mm, that is enclosed with a system of anchorage by bayonet. The ST usually are used in applications of long distance (as corporative networks or campus) and in military applications. FERRULE CONNECTOR (FC) FERRULE CONNECTOR(FC


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

The system of abbreviations and values of reflection of each seems a little confused. We will see one regulates mnemonic

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. concectores fiber


You do not consider numbers 5 and 7

Closet for equipment (Rack)

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.

kit earth

The closet must be firmly fixed to the wall to avoid vibrations, in addition to having a taking to earth.

 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.  

 We will have to peel the cable so that the length of enmeshes agrees with enmeshes of the clip.

 6. Pasamuros.

 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

  1. Solutions Exercise 1.
  2. Connector SC with rule APC
  3. Connector SC monoway
  4. Connector SC fiber multiway
  5. Connector ST monoway
  6. Connector ST
  7. Polished connector ST with different from APC
  8. Connector LC

Connector LC with fiber multiway





7. We will now see the Installation of the lightning rods in antennas

Design PCB