My QO-100 system started life in 2019 not longer after QO-100 was launched, and during that year the system was built. My first QSO via the satellite taking place in the summer of that year.

The core of the system has remained pretty static since that time, but a major re-engineering of the system took place in early 2022 and a number of parts were replaced, usually improving the operation of the system. Compared to approaches involving the Pluto SDR that have become possible since I built my system, my system may seem overly complex. or even outdated.

Components

The current and past components of it are:

• Ice cream cone dish feed, previously a POTY. https://nolle.engineering/en/ice-cone-feed/ and https://uhf-satcom.com/blog/patch_antenna
• Bullseye LNB, previously a GPS stabilised modified Octagon LNB. From Amazon.
• 7m of M+P low loss coax for the transmit signal. From Martin Lynch.
• RG6 for the receive signal. From eBay.
• 85cm dish and heavy block mount, previously a tripod. From eBay.
• IC-705 for the transmit IF on 432 MHz, previously an FT-817. From your favourite emporium.
• Old i7 laptop for the receive side and transmit control, previously a newer i5.
• A combined 739MHz bias-T and downconverter to 144MHz, currently unobtainium due to having come from Ukraine. This is based on the G0MRF design. https://amsat-uk.org/projects/uhf-vhf-receive-converter-for-satellite-lnb
• SG-Labs 13cms transverter, previously GPS stabilised. http://www.sg-lab.com/TR2300/tr2300.html
• SG-Labs 2.4 GHz 20W amplifier. http://www.sg-lab.com/AMP2400/amp2400.html
• A cheap SDR stick. From Amazon.
• SDR-Console running under Windows 10. https://www.sdr-radio.com/Console
• A Meanwell 12V SMPSU turned up to 13.8V, previously a heavy duty 40A SMPSU. From Mouser.
• A Meanwell 24V SMPSU turned up to 28V for the SG-Labs amplifier, previously a buck-converter. From Mouser.
• Various connectors, adapters and such like. Usually from eBay.

Apart from the power supply arrangements, the biggest changes to the system were the replacement of the dish feed from a POTY to the ice cream cone which provided a better uplink signal, but with a slightly weaker downlink signal, only by a dB or so.

The system was originally built when operation on QO-100 was still rather experimental. The idea of locking your receive side to the PSK beacon was not known about so initial systems had GPS locking of the LNB which turned out not to be essential. At the same time I GPS locked my SG-Labs transverter but this was unnecessary and was removed. Removing the locking saved on weight and the number of cables going between the transverter box and the dish feed making the system much easier and quicker to set up. The only loss has been the ability to operate from 12V for potential portable operation.

The original FT-817 transmitter wasn't controlled from SDR-Console so frequency setting was done manually. In the new system the 705 is controlled by SDR-Console allowing for seamless operation.

Photographs

The System as of Summer 2019

The original POTY dish feed and Octagon LNB. The connections to the LNB are for the GPS stabilised oscillator (with the white tape), one for the narrow band transponder, and one for the wide band transponder. This latter connection was never used.

The transverter box. Comparing this with the later image shows that the internal power supplies are missing, but with a Leo Bodnar dual output GPS controller oscillator feeding the LNB and the upconverter.

The equipment in situ at the operating position.

The System as of Spring 2023