The correct BUC Local Oscillator (LO) frequency is essential if you want to transmit on the correct frequency. Acquiring in to a TDMA network or closing a SCPC link with the wrong BUC LO will be impossible and cause interference to other users in the network. Typically from the indoor modem to the BUC is L band frequency and sometimes 70MHx Intermediate Frequency (IF) due to the high losses when higher frequencies are transmitted over coax. The BUC will then convert this frequency with the Local Oscillator (LO) frequency to output the C, Ku or Ka band for transmission to the satellite.
The LO can be found on most manufacturers specs sheet or printed on the label on the BUC. Typical LO’s for C band are 4900 and 7375 MHz, Ku band are 10, 12.8 and 13.05 GHz. You have to select the correct BUC LO for the modem/network (i.e modem L band).
But what if you cant read it or don’t have access to the spec sheet? Well it can be easily calculated by using the BUC frequency range.
Using the example above you can simply use the lower or upper RF range and the lower or upper input frequency range.
5850 – 950 = 4900 MHz LO
6425 – 1525 = 4900 MHz LO