CatSat Team Preparing for Public Linear Transponder Operations
The CatSat team is preparing to open the operation of the Linear Transponder Mode onboard CatSat for use by interested HAM Radio operators.
When the linear transponder onboard is active, CatSat will receive signals transmitted from the ground at 5.663 GHz and retransmit them at 10.47 GHz. The operational bandwidth is 200 kHz wide at these center frequencies. These transmissions are handled through the patch antennas on the -Y face of the spacecraft, with main lobes of about 60 degrees in width. The spacecraft has the capability to rotate and track targets on the surface with these antennas, allowing stations to access the transponder for the full duration of a satellite pass, up to 10 minutes long. Due to power availability on CatSat, activations of the linear transponder onboard are limited to 15 minutes in duration.
The CatSat team has already demonstrated the operation of the linear transponder capability, using a 6.1-meter dish receiving the 10 GHz X-band downlink and a 1-meter dish transmitting on the 5 GHz C-band uplink. During this demonstration, Morse code signals were successfully transmitted and received by the ground station. This configuration far exceeded the capabilities required to utilize the linear transponder on the spacecraft. The team is currently working on building a ground station with commercially available off the shelf (COTS) hardware and 1 meter uplink and downlink dishes to demonstrate the linear transponder on more accessible hardware.
The team plans to schedule transponder operations on the spacecraft on a weekly basis. Once open to the community, interested operators should visit the mission website at catsat.arizona.edu to see the five and dime schedule and to request new dates, times, and places for the mode to be activated. When active, the request form can be found at this link: https://forms.gle/mi8TTgtAyPSxfDWv7
The current plan for testing and commissioning involves the following dates for activation of the transponder. During these passes, the transponder beam will be aimed at the CatSat ground stations in Tucson. All times are given in Tucson time (UTC-7):
October 29th, at ~7:50 PM (UTC 10-30 02:50)
November 2nd, at ~7:45 AM (UTC 11-02 14:45)
November 9th, at ~7:50 PM (UTC 11-10 02:50)
These dates and times are subject to change as commissioning plans evolve.
For more information, please contact the CatSat team members below:
Hilly Paige, W7HIL: hwp@rincon.com
Sarah Li, K7SLI: sli@rincon.com
Walter Rahmer, KK7IOV: wrahmer@arizona.edu