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Antenna Gain

Calculation of the antenna gain in dB.

Dish Diameter

Dish diameter ie antenna diameter in meter. Can be entered with decimals.

Efficiency

Efficiency stands for the efficiency of the antenna in percent. Normally provided by the antenna manufacturer and normally a value between 40 and 70 %.

Frequency

Frequency is chosen for the received signal in GHz. Example: 12,265 GHz. Antenna Gain shown as the result and the result is important regarding choice of LNB gain. Too high gain in total for Antenna and LNB can give Saturation or Intermodulation problems (see ”System Noise figure”).

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System Noise Figure

Calculation of the noise figure in a system, from the antenna to and including the receiver.

Antenna Noise Temp

Antenna noise Temp, usually provided by the antenna manufacturer.

Feed losses

The losses between the antenna (feedhorn) and the LNB. Value is usually 0 to 0.5dB.

Gain LNB

normally 40 to 60 dB. Too high gain in the LNB can cause intermodulation (IP3) or saturation (P1dB) and has to be considered in relation to the size of the antenna. A big antenna (> 1,7 meter) could mean that the LNB gain shall be lower than the typical value. Normally backoff is 10dB from “P1dB value” and 20 dB from “IP3 value”.

Cable loss

Cable loss is the cable loss (in dB) between the LNB and the IF amplifier or receiver. NOTE! Always calculate at the highest IF frequency that is used (1450 MHz, 1750 MHz, 2150 MHz or 3000 MHz).

IF amplifier noise figure

IF amplifier noise figure is the Noise factor of the IF Amplifier. If no IF amplifier is used the value shall be zero.

IF amplifier gain

IF amplifier gain is the gain in the IF amplifier. If no IF amplifier is used the value shall be zero.

Cable loss B

Cable loss B is the cable loss between the IF amplifier and the receiver. NOTE! Always calculate at the highest IF frequency that is used (1450 MHz, 1750 MHz, 2150 MHz or 3000 MHz). If no IF amplifier is used the value shall be zero.

Receiver Noise figure

Receiver Noise figure is the Noise figure of the receiver. See specification of the receiver.

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G/T Antenna gain-to-noise-temperature Ratio

G/T result is a relative total system noise value for the complete system, the higher value the better system performance.

System Noise Figure

See System Noise Figure calculation.

Antenna Gain

See Antenna Gain Calculations.

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C/N Carrier-to-noise Ratio

Calculation of relation between the signal and the noise (Carrier to Noise)

EIRP

EIRP is the radiated power in dBW that the received signal has calculated per square meter in relation to an isotrope.

Dish diameter

Antenna diameter in meter. Can be entered with decimals.

Antenna efficiency

See under Antenna Gain Calculation.

System Noise figure

See System Noise figure calculation.

Bandwidth

Bandwidth is given for the bandwidth of the receiver (Example 30 MHz).

Rain

Rain attenuation for the Ku-band (12 GHz) in SMW-Link.

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Noise Figure / Noise Temperature Conversion

Calculation of relation between Noise figure in dB and Noise temperature in degrees Kelvin.

Noise figure

Noise figure as an example for an LNB is entered and answer for Noise temperature in Kelvin is given.

Noise temperature

If Noise temperature is known but not Noise figure, enter the Kelvin value and you get the value for Noise figure in dB.

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Antenna Alignment

Help for alignment of the antenna.

Latitude

Latitude is entered with two decimals and is given by the distance from the equator. Negative value means that the position is south of the equator.

Longitude

Longitude is value for meridian of the ”North-South” position. 0° is Greenwich (in UK), positive value for positions east of Greenwich and negative value for positions west of Greenwich.

Satellite position

Satellite position is a negative value for satellite position west of Greenwich and positive value for position east of Greenwich.

Azimuth Angle

Azimuth angle is the compass direction towards the satellite position. Calculated for an 360° compass.

Polarization Angle

Polarization angle is the angle that the LNB shall be rotated in relation to 12 a clock. If the calculated value is positive the LNB shall be rotated counter clockwise (CCW). If the value is negative the LNB shall be rotated clockwise (CW). To avoid any problem, it’s recommended to use a measurement instrument for adjustment and optimization of the Polarization angle.

Elevation Angle

Elevation angle is the angle that the antenna shall be turned up in relation to the horizon. It’s recommended to make sure that the mounting pole is 100% vertical and then one can use the elevation scale on the antenna mount to make a preliminary adjustment. For an exactly adjustment you need a measurement instrument.