Replacing an antenna or a passive or active element of a system, generally takes just a few hours work, but these components usually have a high purchase price. On the contrary, the cost of a coaxial cable is pratically negligible if, compared to the total cost of installation, while laying it or possibily replacing it takes many, tiring hours of work.

It is therefore wise to handle coaxial cable more carefully than electric wires, to make the most of its potential, ensuring better reception quality and longer service life.

It is advisable to make a preliminary examination of the place where the TV distribution network is to be laid, with the aid of a sample antenna whose specification are known and a strength field meter.

This makes it possible to test on site the antenna levels of each single broadcaster, whether ground or satellite and, already at the planning stage, to choose the most suitable type of coaxial cable to meet signal levels required by IEC standards at the user’s socket (60-84 dbµv in VHF and UHF bands).

Remember levels that are too low cause "snow" on the TV receiver.

It is advisable to locate the junction box in the common stairwall to make technical service easier.

Right from the design stage we recommend using branches, splitters and sockets of the highly directional inductive type with a good level of shielding. These have a more uniform amplitude/frequency response compared to resistive-type components and therefore better adaptation to the impedance of the cable.

To unwind the cable without twisting it, which causes knots and therefore alters the product specifications it is always advisable to use the CABLEBOX dispenser.

When preparing outdoor sections, on roots or balconies, it is necessary to avoid places where the cable might get trodden on. Where this is not possible, we suggest you run it through suitable tubing.

Likewise, avoid laying the cable in places where puddles may form or where moisture is more likely to accumulate. In some cases it is expedient to run the cable over support materials such as a bricks.

 
 
Just as water and moisture are dangerous, so are places subject to frequent changes in temperature as this ages the coaxial cable faster.
Laying cable too close to a fireplace, for example, subjects the cable sheath to the risk of it soon getting corroreded by deposits of residues of flue gases and liquids for domestic heating.
Lowering coaxial cables through flues and chimneys is definitely to be avoided.

We shall now look at some problems related to laying through raceways inside a building.

If the installer has the opportunity of designing or personally making their allocation, he must bear in mind that they must be at least four times larger than the cable to go inside.

Furthermore as regards bends it is necessary to observe the minimum admitted radius of bending for the cable to be installed.

Raceway joints with other active and passive system components should be located in such a position as to leave ample room around them to make connection easier.

Special care should be taken when inserting coaxial cable into the raceways as it could get damaged by strain caused by hurrying. It should be done by two people with the aid of one or preferably two cable guides. One pulling while the other one taped onto the cable, accompanies it so as not to stretch or break the cable.

In any case, it is a good idea to use lubricants such as talcum, silicone, soap, etc.

Even greater care shoul be taken if it is necessary to insert a coaxial cable into an already crowded raceway.

For sections not inserted in raceways, but simply secured to the wall, clinching machines should not be used as this can alter the concentricity of the coaxial cable. In addition, since the fixing points are repeated at pratically constant distances, the mechanical deformation, from an electrical point of view, causes an accumulation of loss by reflection that can cause double images (analogue system) or shut down the receiver (digital reception system).

It is therefore preferable to use special plastic U-bolts, suitably sized for the diameter of the coaxial cable.

 

Unorthodox connections, ones not made in workmanlike fashion on splitters, should be avoided. Each input or output should be connected to a single coaxial cable, otherwise there will be mismatching between sockets.

An installer should have suitable instruments to check system operation as quickly as possible.

A noise generator with a reflectometer bridge and a panoramic strength field meter, both portable, make it possible to check any type of system with reception trouble, especial with digital signals.

A good strength field meter makes it possible to measure signal intensity, check the spectrum an carry out reflectomer (RL) tests.

In addition, in the digital field it permits checking the arrangement of QPSK - QAM modulations.