Data Network

Data Network

  • Submitted By: ihaider08
  • Date Submitted: 08/13/2010 12:01 AM
  • Category: Science
  • Words: 4402
  • Page: 18
  • Views: 332

Up Link & Down Link Parameters

Center Frequency
Enter the centre frequency of the carrier in GHz. For the uplink, typical values are around 6GHz and 14GHz for C and Ku band respectively. For the downlink, values of 4GHz and 12GHz are typical. The accepted range is 1GHz to 50GHz

This is simply the polarization system adopted by the wanted satellite transponder and is either linear (ie vertical & horizontal) or circular. Enter the letter "V" for vertical polarization, "H" for horizontal polarization or "C" for circular polarization.

Availability % avg. Yr
This form is used to obtain a signal availability figure as a percentage of the worst month for conversion to a percentage of an average year. The latter parameter is assumed for input to the link budget calculation so this facility allows quick conversion if you prefer to work with worst month figures.

For example a signal availability of 99% of the worst month, equates to 99.7% of an average year.

Antenna Diameter
Enter The Value in meter e.g 1.2m 1.8m 2.4m ..

Antenna Efficiency
Antenna efficiency is the amount of incident signal actually collected by the dish and feed, expressed as a percentage. Quality of construction, signal blockage by head units, and method of feed affects this parameter. Most antennas have efficiencies of between 60% and 70%. If you do not know the efficiency of the antenna then enter 60% as a worst case value.

With link budget and dual feed forms, the value entered may be prefixed with a "+" character so the value will be interpreted as a gain, in dBi, rather than efficiency.

Important Note: In the simplified downlink modules (*.dna) and (*.dnd) where automatic downlink antenna sizing is performed the, antenna gain, if entered, is automatically converted to antenna efficiency as the input form is closed. This is necessary since antenna efficiency is relatively constant over a range of dish sizes whereas gain is only valid at the specific dish...

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