Calculation for Dish Size.......

[SENTHIL KUMAR]

All the telecommunication satellites are in the orbit above 36000 Km from earth .(Approximately) .

It delivers signal nearly 225 dB at the satellite end.
But it faces many loss and signal power automatically reduced.
Due to distance from the centre of the foot print , the signal power reduced.

If you are in the foot print area , then easily calculate the size of dish by satbeam.
But you are in the out of coverage area, it is not easy to calculate dish size.

We calculate the dize size by the given formula.

Example : Yahsat 1A @ 52.5 E.

In pakistan the foot print is easily available.

So we calculate the dish size with satbeam.

​

But in my area ( Thiruvarur ) is in out of coverage area.

So we didnot calculate the dish size with satbeam.

​

Here , we apply the values in formula.

CALCULATION.

Formula = 225 - (36.6 + 20 (LOG (FREQUENCY * DISTANCE))


FREQUENCY - 11958 (Eg)
DISTANCE - 2793 km. ( Oman to Thiruvarur ) ( from centre of Footprint to Thiruvarur)

​

(FREQUENCY * DISTANCE) = 11958*2793 = 33398694.


LOG (FREQUENCY * DISTANCE) = 7.523

​

(36.6 + 20 (LOG (FREQUENCY * DISTANCE)) = 36.6 + 20 (7.523) = 187.06

225 - (36.6 + 20 (LOG (FREQUENCY * DISTANCE)) = 225 -187.06 = 37.9 dB.


So the value of signal in Thiruvarur - 37.9 dB.

So , required ku band dish size is = 6 feet ( 180 cm)

 

[SarFa]

Good Share @SK BRO :tup

 

[SENTHIL KUMAR]

Thank you sararaz bro.

It is very useful for out of coverage satellites.

 

[DXer]

Very very useful...
Now I can calculate actual dish size for hotbird in my place...
Thanks

 

[Rahulan Raj]

Nice calculations.

 

[DXer]

What will be the required dish size for 27 db Ku band?

 

[amansingh]

Bro will this work for c band frequency also

 

[Bhanu Prakash ukt]

All the telecommunication satellites are in the orbit above 36000 Km from earth .(Approximately) .

It delivers signal nearly 225 dB at the satellite end.
But it faces many loss and signal power automatically reduced.
Due to distance from the centre of the foot print , the signal power reduced.

If you are in the foot print area , then easily calculate the size of dish by satbeam.
But you are in the out of coverage area, it is not easy to calculate dish size.

We calculate the dize size by the given formula.

Example : Yahsat 1A @ 52.5 E.

In pakistan the foot print is easily available.

So we calculate the dish size with satbeam.

​

But in my area ( Thiruvarur ) is in out of coverage area.

So we didnot calculate the dish size with satbeam.

​

Here , we apply the values in formula.

CALCULATION.

Formula = 225 - (36.6 + 20 (LOG (FREQUENCY * DISTANCE))


FREQUENCY - 11958 (Eg)
DISTANCE - 2793 km. ( Oman to Thiruvarur ) ( from centre of Footprint to Thiruvarur)

​

(FREQUENCY * DISTANCE) = 11958*2793 = 33398694.


LOG (FREQUENCY * DISTANCE) = 7.523

​

(36.6 + 20 (LOG (FREQUENCY * DISTANCE)) = 36.6 + 20 (7.523) = 187.06

225 - (36.6 + 20 (LOG (FREQUENCY * DISTANCE)) = 225 -187.06 = 37.9 dB.


So the value of signal in Thiruvarur - 37.9 dB.

So , required ku band dish size is = 6 feet ( 180 cm)

 

[Bhanu Prakash ukt]

Thanks for the wonderful post sir

 

[Zero7]

Edit : Apologies. Replied on a very old thread and noticed it now.

Thanks for sharing the calculations.
One question, generally Ku beams are geo specific and do not reach the locations outside the footprint is my understanding. Please let me know your views on this.
Even if the signal is catchable with a bigger dish as per theoretical calculation, we may not receive the signals because it's way beyond footprints. Especially, many satellites can be tracked using bigger dish in Northern part of India, here in the south, we can hardly get any. Please clarify.