TurkSat is a 3U CubeSat, the first communication nanosatellite mission of ITU (Istanbul Technical University),
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The VHF/UHF transponder is the main payload to provide two -way radio communications. The VHF uplink has a frequency of 145.990 MHz, the UHF downlink band has a frequency of 435.200 – 435.250 MHz. The transponder consists of amplifiers, filters, mixers and AGC (Automatic Gain Control) stages. The VHF uplink signal is up-converted to the UHF downlink signal linearly. The system has again of 150 dB with 60 dB of the total gain being adjustable. The communication system with transponder has a link margin of 10 dB.
Uplink center frequency | 145.965 MHz |
Downlink center frequency | 435.225 MHz |
Bandwidth | ±25 kHz |
Output power | 30 dBm (1W) |
Receive sensitivity, gain | -120 dBm, 150 dB |
Total power consumption | < 3 W |
Automatic gain control | Yes |
Antennas | Monopole (Cu-Be) |
PCB (Printed Circuit Board) size | 8.8 cm x 8.8 cm x 0.5 cm |
Transponder mass | < 250 g |
Supply voltage | 2.8 V, 3.3 V, 5 V DC |
Microcontroller | MSP430F5438 |
Specification of the transponder system
Illustration of the transponder desktop model (image credit: ITU)
Antenna system: The communication system consists of three subsystems with their backups: the modem, transponder, and the beacon.
System | UHF Antenna (435 MHz) | VHF Antenna (145 MHz) | No of antennas |
Transponder | 2 | 2 | 4 |
Modem | 2 | 2 | 4 |
Beacon | 2 | - | 2 |
Total | 6 | 4 | 10 |
Antenna system of the satellite communication subsystem
Source eoPortal