Senin, 27 Agustus 2012

Tests for the new transmission systems (type approval/type acceptance tests)

Tests for the new transmission systems (type approval/type acceptance tests)

In connection with the implementation of new technology or as a result of a tender process it is always necessary to test in detail new transmission systems before they are integrated into existing networks.
It is of course the case that all manufacturers guarantee the conformity of their products with international standards, however it happens time and time again — above all in the complex interaction with existing systems of different suppliers — to unexpected incompatibilities.

On the basis of my wide and highly differentiated experience of many years I am in a position to develop and implement test scenarios which are both practical and customer-specific, and these tests differ greatly from traditional test procedures recommended predominantly by the manufacturers. My services cover all types of microwave link systems as well as multiplexer, ATM and IP technology, including Ethernet.

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Measuring of the transmission equipment in the test laboratory within the typ

Planning of individual microwave links or networks of all sizes

Planning of individual microwave links or networks of all sizes

In addition to the feasibility study already described the planning comprises as a rule following ongoing additional services:

Map Survey

  • Reviewing the exact location coordinates
  • Preparing a provisional path profile
  • Determining the optimum antenna heights
  • Determining azimuth and elevation
  • Provisional calculation of the transmission quality
  • Determining the appropriate frequency band
  • Provisional antenna configuration

Site Survey

  • Collecting all location-based information relevant to the microwave link like for example service room, power supply, possibilities of erecting indoor units, distribution frames and interfaces to other network elements, cable ducts, grounding points
  • Determining the exact antenna location
  • Definition of supplementary reference points for the later alignment of the antennas (important above all for long-haul paths)
  • Determining the required civil work to be carried out at the location (mounting pole, lightning protection, wall grommets, cable trays, etc)
  • Checking for obstacles in the antenna near field, possibly LOS testing (For short-haul links, above all over densely built-up area, a LOS test is normally unavoidable)

Path Survey

  • Checking for possible obstacles in the transmission field and also making an exact survey of them
  • Checking for sources of possible secondary reflections
  • Checking the area around the calculated reflection point with respect to surface, humidity, buildings and vegetation, and making surveys of obstacles
  • Checking for construction work that could be an obstacle in the future
  • Evaluation all data affecting the microwave propagation
  • Final calculations of the transmission performance
  • Final determination of the optimum antenna configuration
  • Frequency planning and interference analysis

For short-haul microwave links the activities of the path survey are usually made together with the site survey.

The planning documentation comprises calculations, path profiles, sketches, text descriptions and commentaries and also true-to-life and informative photographs.

You can use the planning documentation as a basis for comparing tenders of a number of equipment manufacturers.

Feasibility studies for microwave link applications

In contrast to the entire planning stages, the feasibility study carried out first of all is restricted to a general analysis of whether microwave technology or another medium is best suited to solving your problem or not.

Depending on the concrete existing conditions, a feasibility study includes in general following steps:

  • Analysis of the problem to be solved
  • Touring the locations to be investigated and the visual inspection of the conditions to be found here (site survey)
  • Checking the line of sight (LOS test) providing this is possible without significant difficulties
  • Evaluation of the basic possibility of constructing the desired link

The results of the feasibility study will be presented in a summarised form in a written report. According to the terms of reference this report could also include suggestions for civil work, general technical requirement, adaptation of interfaces and also recommendations for the most suitable equipment as well as alternatives.

The feasibility study will put you in a position to estimate the costs involved and to come to a decision based on the project's overall economic feasibility.

Should the feasibility study reveal that a direct microwave link is not possible, I shall be pleased to act on your behalf and look for suitable locations for active or passive repeater stations — investigating among other alternatives the possibility of renting existing microwave infrastructure of other network providers.

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