AO-73 (FUNcube-1) – Image credit Wouter Weggelaar PA3WEG

After a year long period of ‘battery management’, AMSAT-UK and AMSAT-NL have restarted the transponder on AO-73.

After 10 years in orbit, the battery on the satellite has reduced capacity and until recently, has been unable to charge to the nominal 8.3V.
Following some careful battery management, where the transmitter was off during eclipse, the battery status has improved and the transponder has been reactivated.

Although the battery voltage is varying between 8.13 in sunlight and 7.8V at the end of eclipse, this is much improved on the situation earlier in the year.

Low power BPSK telemetry is transmitted on 145.935MHz
The inverting mode U/V transponder input is 435.130 to 435.150MHz
The transponder downlink is 145.970 to 145.950MHz

At the moment the satellite has a high spin rate of apx. 30 rpm and if you’ve not used AO-73 before, the downlink can be Doppler tracked successfully, but the input on 70cms is best tuned manually due to temperature drift of the receiver.

73

David G0MRF – AMSAT-UK

Signal received from FUNcube-1 at National Radio Centre Bletchley Park, Nov 21, 2013

November 21, 2023, marks the tenth birthday of our very first CubeSat mission, FUNcube-1 (AO-73).

A very short time after the launch from Yasny in Russia and within a few minutes from deployment, the very first frame of data from the low power transmitter on board, was detected and decoded by ZS1LS in South Africa. He was able to relay the data over the internet from his Dashboard to the Data Warehouse and the numbers, appeared, as if by magic, at the launch party being held at the RSGB National Radio Centre at Bletchley Park.

ISL03 Mission Patch

After a very brief check out, the FUNcube team were able to switch the transmitter to full power, again at the very first attempt, and were quite amazed at the strength of the signal from the 300mW transmitter on 145.935 MHz. The transponder was then switched on and successfully tested, the first contact was between G6LVB and M5AKA who were both operating from the Bletchley Park car park.

The team finished the day with a request to AMSAT-NA for an Oscar number and were delighted to receive the AO73 Oscar 73 designation!

Since then, FUNcube-1, with a launch mass of less than 1kg, has operated continuously with only a very few interruptions. In excess of 53,500 orbits, 1.3 billion miles travelled, 61 million telemetry data packets transmitted, and with more than 10.9 million unique data packets downloaded and stored in the Data Warehouse.

The FUNcube team still receive many requests for Fitter message uploads for school events…please contact us by email to operations@funcube.org.uk giving us at least two weeks notice.

The FUNcube team continue to be very grateful to all the many stations around the world that continue to upload the telemetry that they receive to our Data Warehouse. They really need this data to provide a continuous resource for educational outreach.

FUNcube Data Warehouse and the Dashboard software
https://funcube.org.uk/working-documents/funcube-telemetry-dashboard/

FUNcube email group https://groups.io/g/FUNcube

FUNcube Website http://www.funcube.org.uk/