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Transponder Frequency conversion as per LNB Frequency - Printable Version

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Transponder Frequency conversion as per LNB Frequency - vinay_kumar - 04-04-2013

Friends,
Some of the members have very old satellite receiver set-top boxes. The limitation in those stbs is that the frequency input (that is LNB Frequency, Transponder Frequency) is only upto 4 digits like say 5150MHz for LNB Frequency is fixed. Thus the user thinks that it is only a C-band satellite receiver and cannot receive Ku-band channels.
But that is not true. A satellite receiver stb can receive C-band as well as Ku-band (unless particular band restriction is specified). Its the LNB chosen for that band reception that makes it possible.
That means a DD Direct Plus DTH receiver stb can also get C-band channels in MPEG2 DVB-S if its connected to a aligned bigger dish with C-band LNB.

Ok lets say your old stb has this 4 digit frequency input only. So here we see how to calculate and convert the 5 digit frequencies to go well with the receiver and ensure good Ku-band channels reception.

Consider B4U Movies on DD Direct Plus DTH...Parameters are Transponder Frequency:10990MHz, Symbol Rate:27500Ksps, Polarization: Vertical, Video PID: 513, Audio PID: 613.


Quote:As a rule of Ku-band, if Transponder frequency is less than 11700MHz, then LNB Frequency will have to be kept 9750MHz and 22K Tone=OFF
And if its greater than 11700MHz, then LNB Frequency will have to be kept 10600MHz and 22K Tone=ON.
So now when you see a Ku-band transponder on Lyngsat, Flysat etc, you should be able to know what to keep LNB Frequency

Lets come back to the 4 digits world Big Grin
Then we keep/have LNB Frequency 5150MHz and Transponder Frequency for B4U Movies will be 5150 + 9750 - 10990 = 3910MHz
Rest all Symbol Rate, Polarization, Video PID, Audio PID etc will remain the same.


Now lets see a transponder frequency greater than 11700MHz, typical example Zee Punjabi on Dish tv's NSS6 satellite...Parameters are Transponder Frequency:12688MHz, Symbol Rate:27500Ksps, Polarization: Vertical, Video PID: 4531 , Audio PID: 6116.


We keep/have LNB Frequency 5150MHz and Transponder Frequency for Zee Punjabi will be 5150 + 10600 - 12688 = 3062MHz
Rest all Symbol Rate, Polarization, Video PID, Audio PID etc will remain the same.


Some old private DTH boxes like that of Videocon d2h are capable of receiving FTA channels due to unlocked software can receive C-band channels with frequencies converted into 5 digits by reversal of above formula.


RE: Transponder Frequency conversion as per LNB Frequency - Sathish - 04-05-2013

Very nice information Mr.Vinay Smile


RE: Transponder Frequency conversion as per LNB Frequency - vinay_kumar - 04-05-2013

Actually the old software version private dth set-top boxes like Sun Direct, Videocon d2h were able to receive C-band channels by converting C-band frequency into 5 digit Ku-band style numbers.

To convert C-band satellite frequency into dth box type 5 digit number:

Lets take 3600MHz as the C-band frequency to be converted into 5 digits and falling within Ku-band range of 10700MHz to 12750MHz.



With LNB Freq set as 9750MHz:
5150 - C band tp freq from Lyngsat 9750.

example 5150 - 3600 9750 = 11300 MHz ...keep 22K Tone=OFF

With LNB Freq set as 10600MHz:
5150 - C band tp freq from Lyngsat 10600

example 5150 - 3600 10600 = 12150 MHz... keep 22K Tone=ON


RE: Transponder Frequency conversion as per LNB Frequency - zeeshan004 - 08-19-2014

nice dear, searching for this for many days..


RE: Transponder Frequency conversion as per LNB Frequency - ravindranchennai - 09-05-2015

Excellent informatrion , Mr.Vinay.