P3E Microwave Transponder

Michael Fletcher, OH2AUE has provided a progress update on the 2.4 to 10 GHz linear transponder for the Amateur Radio satellite P3E.

On the AMSAT bulletin board he writes:

AMSAT-OH is working on the S/X band coherent/linear transponder for P3E. The Coherent mode is a fully functional testbed for the P5A (Mars Orbiter) ranging transponder.

Especially the linear transponder prototype has been assembled and verified with over-the-air tests and laboratory tests. Flight versions of the submodules have been and are being produced at this time with our eyes now set on integrating these together and cabling the whole job together.

Full verification of the Coherent Mode requires a fully functional command station AND a functional IHU + CAN environment to interface our data ports with. No such tests have been available yet, but all our preliminary testing and evaluation of the Coherent Processor have shown proper operation of the design and circuitry (e.g. locking onto a "modulated" uplink carrier, tracking this etc.). So far correct live operation of the Coherent Mode is our biggest question mark.

Our national team meets on a regular basis every 4 - 6 weeks for testing and follow ups of the work of each individual.

This transponder is especially complex as you can see from these key figures:

• 9 different local oscillators
• All local oscillators locked to the common 10 MHz USO
• 21 different frequency mixers
• 13 different intermediate frequencies
• Linear Mode output power on 10 GHz: 3 W PEP
• P5A Mode output power on 10 GHz: 1 mW PEP
• 38 control lines on the CAN interfaces
• 2 CAN interfaces, one in multiplexed mode
• 4 dedicated direct control lines interfacing with the IHU
• 14 analogue telemetry lines to the CAN bus
• Coherent Mode Uplink/Downlink ratio is fixed at 30:7

There is further information in Google English on the
AMSAT-OH website at
http://tinyurl.com/AMSAT-OH

P3E
http://www.p3e-satellite.org/index.pl?lang=en_EN

P5A
http://www.ticket-to-mars.org/