5150 Mhz in C band LNB- Explanation.

[SENTHIL KUMAR]

The signal that is transmitted from a satellite is called the FUNDAMENTAL FREQUENCY. ( 3400 Mhz to 4200 Mhz ). This is C band frequency.

It is reflected by the dish and sent to a receiver to be demodulated into the separate video and audio signals.

In practical ,FUNDAMENTAL FREQUENCY is not suitable to transfer by cable. Because cable loss is very high in FUNDAMENTAL FREQUENCY.

But, INTERMEDIATE FREQUENCY is suitable for transmission through cable, because there is no loss in this range. It is range from ( 950 Mhz to 1750 Mhz ).

So we introduce one more frequency called LOCAL OSCILLATOR FREQUENCY ( 5150 Mhz ) by receiver. This is called C band LO - 5150 Mhz.

The satellite receiver inject the 5150 frequency to the LNB by cable to convert the FUNDAMENTAL FREQUENCY into INTERMEDIATE FREQUENCY .

Now calculate,

5150 - 4200 = 950 Mhz.

5150 - 3400 = 1750 Mhz

Now we get the INTERMEDIATE FREQUENCY 950 Mhz to 1750 Mhz. This is easily transmited through cable without any loss. So we get the full signal at receiver end.


So, 5150 is called a C band LNB Frequency.

That is the reason , C band satellites transmit the range - 3400 to 4200 only.

 

[M.J.Sadiq]

Good info Senthil. And welcome to DDF.

Off topic:
Great to see that you are from Thiruvarur. I am from Karaikal.
Today I visited Thiruvarur...

 

[Arul]

The signal that is transmitted from a satellite is called the FUNDAMENTAL FREQUENCY. ( 3400 Mhz to 4200 Mhz ). This is C band frequency.

It is reflected by the dish and sent to a receiver to be demodulated into the separate video and audio signals.

In practical ,FUNDAMENTAL FREQUENCY is not suitable to transfer by cable. Because cable loss is very high in FUNDAMENTAL FREQUENCY.

But, INTERMEDIATE FREQUENCY is suitable for transmission through cable, because there is no loss in this range. It is range from ( 950 Mhz to 1750 Mhz ).

So we introduce one more frequency called LOCAL OSCILLATOR FREQUENCY ( 5150 Mhz ) by receiver. This is called C band LO - 5150 Mhz.

The satellite receiver inject the 5150 frequency to the LNB by cable to convert the FUNDAMENTAL FREQUENCY into INTERMEDIATE FREQUENCY .

Now calculate,

5150 - 4200 = 950 Mhz.

5150 - 3400 = 1750 Mhz

Now we get the INTERMEDIATE FREQUENCY 950 Mhz to 1750 Mhz. This is easily transmited through cable without any loss. So we get the full signal at receiver end.


So, 5150 is called a C band LNB Frequency.

That is the reason , C band satellites transmit the range - 3400 to 4200 only.

Please let me know the dish antenna diameter required to transmit 5150 MHz frequency