Listening for the CAS-5A Chinese satellite at 435 MHz - 15th Dec 2022

CAS-5A is a Chinese amateur radio satellite which was launched from the Yellow Sea off China on the 9th of December 2022. It's an unusual satellite in that it has transponders with an downlink in the 70cms band and uplinks on the 2m VHF band and the 15m HF band.

Today on the 15th of December 2022, I did a quick test to see if I could hear it. The pass was from 15:18 to 15:30 UTC with the satellite reaching a maximum elevation of 44 degrees above the horizon. 

The satellite has a CW beacon on 435.570 MHz so I left my radio listening on that frequency on USB. My antenna was a very modest home made colinear vertical antenna in the attic of my house.

My primary objective was to catch the doppler shift of the beacon and my secondary objective was to listen for any activity in the transponder passband.

The image on the left shows the audio spectrum of the received audio from my radio. The trace showing the drifting CW beacon can be clearly seen. In the space of just 15 or so seconds, the CW signal had moved downwards about 1KHz in frequency due to doppler shift. 

As you might imagine, this make manual tuning of a CW or SSB  signal on the 70cms band quite a challenge and confirms the need for some sort of CAT software to control the frequency of the radio to compensate for the doppler.

The signal of the CW beacon was also quite weak and was just above the noise. I'm sure that a pass overhead would probably be stronger but the beacon is still only 100mW to a whip antenna. The test confirmed to me that a small crossed Yagi antenna would probably be much better.

As for activity on the satellite, I did tune upwards after the beacon test and I could hear the weak warble of a FM signal on SSB but it was too weak to hear on FM mode.

The CAS-5A satellite has been given the AMSAT name of FO-118. A users manual for the satellite can be viewed HERE

Video: Guide to launching amateur radio payloads by balloon... by VE3KLX

 

At the virtual Radio Amateurs of Canada conference last September, teacher Kelly Shulman, VE3KLX gave an interesting presentation about launching amateur radio payloads on high altitude balloons.

As the video below highlights, high altitude balloons and scientific experiments can make amateur radio relevant to a younger generation. In terms of cost and technical ability, many schools might aspire to doing their own high altitude balloon experiments where as a cubesat / satellite would be out of the question.

Links...

1) Kelly Shulman's website... http://shulman.x10host.com/

AMSAT-UK announce a new satellite project...FUNcube

I came accross this a few days ago. It looks like an interesting satellite with a linear transponder as well (2m/70cms). Here are some details...

"AMSAT-UK has announced a new amateur satellite project – FUNcube – that features a 435 to 145 MHz Linear Transponder for SSB/CW operation.

FUNcube is an educational single cubesat project with the goal of enthusing and educating young people about radio, space, physics and electronics.

The target audience consists of primary and secondary school pupils and FUNcube will feature a 145 MHz telemetry beacon that will provide a strong signal for the pupils to receive.

It is planned to develop a simple receiver board that can be connected to the USB port of a laptop to display telemetry in an interesting way.

The satellite will contain a materials science experiment, from which the school students can receive telemetry data which they can compare to the results they obtained from similar reference experiments in the classroom.

FUNcube is the first cubesat designed to benefit this group and is expected to be the first UK cubesat to reach space.

It is anticipated FUNcube will be launched into a Sun Synchronous Low Earth Orbit about 600-700km above the earth using one of the many launch opportunities that exist for Cubesat missions. In such an orbit the satellite passes over Europe approximately 3 times in the morning, and 3 in the evening, every day, perhaps allowing the morning passes to be used for educational purposes and the evening passes for Amateur Radio communications.

FUNcube will carry a UHF to VHF linear transponder that will have up to 1 watt and which can be used by Radio Amateurs worldwide for SSB and CW communications.
Measuring just 10 * 10 * 10 cm, and with a mass of less than 1kg, it will be the smallest ever satellite to carry a linear transponder and the choice of frequencies will enable Radio Amateurs to use their existing VO-52 or DO-64 station.

A key feature of the satellite is the absence of an On-Board Computer. For reliability and maximum power efficiency, the design has been kept as straight-forward as possible with satellite control being achieved using simple commands. "