Block Upconverter (BUC) converts a band of frequencies. It is used to convert the frequency from lower to higher. BUC is used in the transmission of satellite signals. BUCs are used to convert L band to Ku band, Ka band, and C band. X and S Bands. Previously Up Converters were used but were less efficient as they used to convert 70 MHz intermediate frequency to C band or Ku band.
Many Block Upconverters use phase-locked loop local oscillators. They also require an external 10 MHz frequency reference in order to maintain the exact transmit frequency. The Block Upconverters used in remote locations are usually 2 or 4 W in the Ku band while 5 W in the C band. Usually the engineers send 10 MHz reference frequency on the same feedline as the primary carrier. In case of smaller BUCs direct current (DC) supply is fed over the feedline utilizing an internal DC block.
Generally, the Block Upconverters are used in conjunction with the low-noise block converters (LNB). Since BUC is the up-converting device, it makes up the “transmit” side of the system, on the other hand, LNB is the down-converting device, so it makes up the “receive” side.
VSAT (Very Small Aperture Terminal) system used for bidirectional access via satellite is the perfect example of the utilization of both BUC and LNB.
The BUC is a block-shaped device recognized when assembled with the LNB in association with an OMT (orthogonal mode transducer) to the feed-horn facing the reflector parabolic dish. They also might be rack mounted indoors or not co-located with the dish.