Satellite receiver tuning offsets
These are the calculations for tuning a satellite receiver where the receiver has the LO frequencies already calculated in it. EG, if your free to air receiver looks like it tunes to frequencies like 11675MHz and you want to use it without an LNB or a non stock one then this is what you need:
- The Local Oscillator frequency (LO) of your LNB - normally 9750 or 10600 for a Ku band or 10 GHz LNB. C band LNBs to receive 3.4GHz have an LO of 5150
- The frequency you want to receive
- The LO of the LNB your receiver is designed for (normally 9750) and thinks it has.
With these numbers you can calculate the frequency you need to tune the receiver to:
Example 1 - If you want to receive without an LNB, eg for 23cs, it's simply the frequency you want to tune to + the stock LNB frequency.
To get 1255MHz on a normal receiver its...
1255 + 9750 = 11005MHz
So I tune the receiver to 11005MHz and there it is.
Example 2 - where I have an LNB which is not listed in my satellite receiver.
My new C band LNB to receive GB3HV has an LO of 5150MHz
MY satellite receiver is expecting a normal LNB with and LO of 9750MHz
The local repeater is on 3408MHz
So 5150 - 3408 + 9750 = 11492
So I tune the receiver to 11492 and there it is.
The math is a bit different behind it as the LO's are high side for most LNB's. I'm sure there is a generic sun that would do it all with a LO of 0 (zeor) for direct reception but I can't work it out at the moment.