April 17, 2013

Nanosatellite linear transponder (4) Delfi-n3Xt

Delfi-n3Xt (Delfi Triple CubeSat NeXt) is another Nanosatellite from Delft University of Technology (TU Delft) with liner transponder. Launch is scheduled for Jul 2013.

Compared to Delfi-C3, Delfi-n3Xt will be equipped with batteries, an active ADCS, and a high-speed S-band transmitter.

The Communication Subsystem will carry no less than three radios:

The PTRX (Primary Transceiver)
provides an UHF (435 MHz) up-link at 600 or 1200 bit/s. The down-link is in VHF (145 MHz) at 1.2 or 2.4 Kbit/s. The PTRX is of Delfi-C3 heritage. The PTRX is further complimented with a linear transponder (UHF up, VHF down) . And might also be equipped with an experimental OLFAR (Orbiting Low Frequency ARray) transponder for very low frequencies.

The payload ITRX (ISIS Transceiver)
The frequency bands used by the ITRX are VHF for down-link and UHF for up-link. The data rates are 1200 bit/s for up-link and a maximum of 9600 bit/s for the down-link, which can be variable. The maximum transmitter power will be at least 400 mW,
Besides flying as a payload, the up-link receiver of the ITRX can be used as a backup command receiver for commanding the satellite. Furthermore, the transceiver will be used for ranging purposes, whereby the transceiver acts as a transponder.

The high-speed STX (S-band Transmitter).
The STX (S-band Transmitter) of 2.4 GHz provides variable down-link data rates between 9.6 and 250 Kbit/s.

In addition, there is the antenna subsystem consisting of at least 9 antennas. Four UHF up-link antennas are positioned alongside the solar panels, and four VHF down-link antennas are mounted canted turnstile at the far end of the satellite. The high-speed S-band down-link will use one or multiple patch antennas. 

Source : eoportal.org

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