When we do antenna installations we specially take note of the following issues:
VTS measures elevation with the age old trusted tape measure. This is the most accurate measuring method, but we also apply a specially designed laser measure.
VTS has invested in the most modern equipment for determining the direction of antennas. It is advanced GPS equipment, specially designed to adapt antenna directions. The instrument has an incredibly high accuracy with a measuring inaccuracy of only 0.2%.
For direction determination we use the Indian map and property registry, Court organisation. We take a look at high buildings a short distance off the installation, e.g. a church tower, which may be used as a direction indicator. Instead of a compass we orient ourselves with reference to the buildings, because it is far more accurate. The VTS telecommunications fitter uses a cell aligner instrument for this purpose. This is a digital degree measuring instrument, which is put onto the back of the antenna, and thus performs an accurate determination of the direction.
To tilt the antenna the fitter uses a digital block level. This helps him tilt the antenna up or down to exactly the desired degree. Of course this happens with reference to client specifications received from the client’s network- and radio planning department. They have the overall view of the entire network and the planning.
There are different types of antennas. The difference lies in the system they are used for.
VTS specialists have in depth knowledge of the different systems and antennas and therefore they can quickly identify if the antenna is adequate for the specific installation or not. Our client is therefore safe from installation mishaps.
The most common antenna systems are:
In each category there are several different antenna forms and types.
In connection with the installation of panel antennas, respect distances must be maintained both vertically and horizontally in order to avoid interference.
In the following we have noted the minimum respect distances for GSM and UMTS:
For GSM panel antennas the vertical respect distance is no less than 0.50m and the horizontal respect distance is no less than 3.3m.
For UMTS panel antennas the vertical respect distance is no less than 1m. The horizontal respect distance is no less than 2/18m with one operator and 8/34 with another.
One operator describes the problem thus:
The horizontal respect distance is 8m, when the angle between the antenna directions is less than 120 to 180 degrees. If the existing antenna points directly towards the UMTS antenna with a maximum of 60 degrees difference, the horizontal respect distance is enhanced to 34m. In case doubt arises, the other operator is requested to allow co-existence. The problem is then clarified in the correct way.
For transmission the most commonly used micro wave antennas are Ø30/Ø60 MW links. MW can be mounted between the panel antennas or immediately over or under them.
The vertical respect distance can be used for MW links, since the MW beam is compact and forms a straight line between site A and site B. When installing an antenna position, respect distances to the other operators must be kept. Typically, this is agreed on between the operators and different operators have different respect distance requirements.
Respect distances are included in the project process of each installation before the installation is put into production and realised.
A jumper cable is the connector between the feeder cable and the antenna, and the feeder cable and the equipment.
Jumpers are used to ease the installation of the antennas. The jumper is fitted between the last piece of feeder cable and the antennas. Feeder cables, measured in inches, are thicker than jumpers and have a larger bending radius than the jumper.
Therefore, it is easier to install the antennas. Another piece of jumper is fitted to the technical equipment. Again, fitting flexibility is the aim.
Feeder cables have larger dimensions than jumpers and therefore they have a larger bending radius than jumpers have. Feeders are therefore not as flexible to fit. By using a jumper, you in fact have a smaller feeder cable with an extreme flexibility.
Size of feeder cables
There are different sizes of feeder cables. The longer the distance between the equipment and the antennas, greater is the loss of signal. In larger dimensioned feeder cables more signal can be carried further.
To compensate for the loss, larger dimensioned feeder cables are used. Thus the resistance, and in turn the loss, in the cable becomes lessened.
Feeder sizes and recommended usage with reference to the distance between equipment and antennas are listed here:
1 ¼” 35-45m
1 5/8” 45-65m
VTS only uses feeder cables of accredited quality standards. The decisive choice of supplier rests on the equation of quality and price. Our feeder cable suppliers are:
In UMTS installations feeder cables of larger dimensions are used for shorter distances, thus differing from GSM installations, as referred to above.
Cable trace for the feeder installation
To trace a cable existing leads and openings in the building can be used, and VTS does its best to use e.g. dust bin shafts, chimneys, etc. Here the feeder cables are fitted to a cable tray with or without cover.
Our choice of cable trace is based upon the intention to find the shortest way between the antenna and the technical equipment to avoid unnecessary loss of signal. We also try to make use of the easiest way, since we have cost efficiency on behalf of our client in mind, as well.
VTS employs accredited electrical installers and the company can therefore realise all types of electrical work.
When we precede the building process of an antenna site, we make sure that service conductors are buried, we keep contact to the power supply companies for subscription of the installation, and we install power metres and perform general electrical work on site as well as drive tests of the finished power installation.
Services in the area of electrical installations
In addition to all the electrical work connected to building a telecommunication site, we also perform all other electrical tasks for our clients. If you have a task in the field of electrical installation, do not hesitate to contact us for a non-binding offer.
When VTS builds an antenna installation, we naturally ensure that all metallic parts in the antennas, feeders, fittings, cable traces, equipment, etc., are connected to earth to protect from lightning strokes as well as to equalise the potential in all parts and thus avoid differential tension. As always, earthing is performed according to the client's requests regarding any such earthing system and we are always ready to assist with expert counseling in respect to this field.
We force an earth rod to a certain depth into the ground. Later we perform measurements with a special measuring device, called an earth plate measuring device. It indicates the transition resistance towards the earth, and this resistance needs to match the client's specifications. Should this not be the case, we force more earth rods into the ground until the desired transition has been achieved. Afterwards we install a downward conductor.
In the following, we describe the process of an earthing installation in buildings and pylons in connection with telecommunications installations.
Earthing systems on buildings in connection with telecommunications installations
VTS performs earthing installations on buildings by forcing an earth rod into the ground at the side of the building, and proceeding until the desired transition to earth has been achieved. Later we install a downward conductor from the roof top of the building. Depending on the possible trace, the downward conductors are connected to the prepared earth rod installation.
In respect to the trace, we prefer existing paths, such as garbage shafts, power supply traces, ventilation shafts, or other shafts, or as the last resort we lead the trace downwards on the side of the building. We are aware that visually, this is the worst option.
When two or more operators are situated on one building, it is usually required that we install in a way that allows for equalisation between the different earthing systems.
It is up to each individual operator to agree to share existing earthing systems. If the operator, who has established the original earthing system, chooses to remove his antenna site, the operator sharing may find himself in a situation where he has to establish a completely new earthing system. Therefore many operators choose to establish their own earthing systems, when establishing their antenna site.
When pylons need earthing systems, we establish circle earthing.
Circle earthing means that VTS sets earthing rods in the ground around the mast. The earth conductor is connected to all four/three legs and then to the earth rods that we force into the ground at the edge of the foundation of the pylon. Afterwards we connect the installation to the equipment shelter, in order to secure earthing here, as well.
Installation of Radio and Transmission Equipment
VTS handles installation, tests and commissioning of radio equipment from the largest suppliers in the market, and we specialise in Nokia and Ericsson equipment.
We take care of mounting and configuration from the very beginning until the site is on air and we have ample competence within base stations, transmissions, drive tests and EDGE-technology.
We have thorough knowledge and experience in the following areas:
Installation of transmission via Microwave Link, Lease Line or Fibre
VTS also handles everything about EDGE-technology – installation, integration and trouble-shooting.
VTS has great experience in performing drive tests on our sites. The tests are performed after the installation of the equipment, but before the hand-over of the project.
We thoroughly investigate if the signal functions optimally, and if adjustments need to be made before the project is handed over to the client.
Amongst other equipment, we have Ericson TEMS measuring equipment preinstalled into our vans – this is the best equipment in the market for this purpose – and our staff has the radio technical expertise to find and remedy defects immediately. This way we adjust any deficiencies before the site goes on air. This saves valuable time and in the end time is money - especially for our clients.
We are honestly concerned with securing high and uniform quality for our clients. Therefore, we have extended our staff with our quality manager, whose primary task it is to guarantee the maintenance of VTS s high standards in all steps of business.
If complications arise in our production, we have a refined system to detect and amend faults. Every time such a fault is detected, we re-evaluate our procedures to find out if we can make an effort to become even better yet. VTS is furthermore well on its way towards an ISO 9001 certification.
To ensure a uniform quality for all of our clients, we have woven a great number of quality procedures into our work process. These procedures ensure that all work supplied by us is of a uniform high standard and quality, every single time. As part of our quality assurance we also always ascertain that a task is checked by internal control, before it is handed over to the client. This provides our clients with a ready, operational product, without defects or flaws, which saves time and money for VTS as well as our clients.
Thorough documentation is always supplied in unison with our services. Documentation is designed as an AS BUILT document in absolute accordance with the client's specifications. This applies to almost every type of installation and has the purpose of allowing the client and ourselves to return to the basics and to ensure the amendment of faults, if any are detected. Furthermore, this provides the client with assurance that everything is performed in accordance with the signed agreement.
Often exceptional conditions apply, when we install indoor solutions. Usually, such a project is solved by placing small antennas in strategic locations.
The challenges in these installations include:
Through time, we have developed into experts in this area and have supplied well functioning installations for Siemens and others.
Drive test of radio coverage
VTS has ample experience in performing drive tests on our sites. The tests are performed after installation, but before hand-over of the project. We thoroughly investigate whether the signal functions perfectly or if adjustments are needed before the project is handed over to the client.
We have Ericssons TEMS measuring equipment installed into our service cars, knowing that it is the best available measuring equipment in the market for this purpose. Our staff has the radio technical expertise to detect flaws and faults immediately and mend and repair them at the same time. Thus we rectify any problems before the site is put on-air. This saves valuable time and as a result also our client's money.
During the drive test, we investigate signal quality and strength, the hand-over functionality, and amongst other things execute a performance optimisation.
Line of Sight
In connection with the mounting of links (Micro Wave), VTS performs all tasks relating to Line-of-Sight. Our dedicated staff consists of high level specialists in the area, concerning Nokia as well as Ericsson equipment.
The objective with the line of sight is to ensure a link between to defined points in order to create stable data transmission. It is a precondition in this respect that there is a direct view or Line-of-Sight between the two defined points in a specific height. To ensure this, either helium balloons or strong light beams which is seen between the two points is used in the preoperational tests. Furthermore, it is possible to achieve a line-of-sight with a camera with an especially powerful zoom designed specifically for this purpose.
In order to perform this task it is vital to have staff knowledgeable in the sender as well as the receiver position of networks. VTS has experienced specialists, who know the different methods and have solid experience in the area. They are perfectly capable of handling all imaginable situations within the area and secure that the network traffic is directed optimally between the two defined points.