**4.5 TTC**

For Telemetry and Telecommand, the University of Surrey heritage satellite stopped using low frequency (UHF and VHF) after KITSAT-3. Such usage in RASAT is only in emergency situation. Meanwhile, in the TU Berlin heritage, UHF TTC is still used until LAPAN-IPB. The advantage of using low frequency for TTC is on its omni-directional antenna. Therefore, the satellite can always be contacted by its ground station, regardless of its attitude. The cost of the satellite's control ground station is also much lower. However, the risk for frequency noise for its operation is also higher.
