Cutting-edge diy projects
I caught the last transmission of OSIRIS-REx with its high-gain antenna pointing towards Earth before it started to slew to its burn attitude. A few minutes later Goldstone reacquired it but at -154 dBm, which is much too feeble for my amateur DSN system.
The system is running automatically at home with me monitoring it from work.
Sanity check after moving the X-Band system from the 1.2m offset dish to the 3.5m dish. OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) spacecraft comes in strongly two days before its first sampling attempt of asteroid Bennu.
New one to me: received the fast-moving Mars Atmosphere and Volatile EvolutioN (MAVEN) orbiter while locked to Madrid DSN using the 1.2m offset dish antenna.
I’ve been working on my system for receiving signals from deep-space spacecraft since the summer of 2019 when KC2TDS and I built an X-band circular polarization feed and downconverter that we tested at MUD 2019.
My first true-DSN X-band reception happened in May 2020. I was able to receive and track Bepi-Colombo, which at that time was 15.2 million km away from Earth. The signal was received with the feed built by KC2TDS mounted on a 1.2m f/d=0.6 offset dish steered by a Yaesu G-5500 az/el rotator. I used a Kuhne LNA-8000B low-noise amplifier connected directly to the probe, and the amplified signal was sent to the N2QG downconverter (LO=8GHz) mounted on the boom. Downconverted signals (400 – 450 MHz) were received using an AOR AR-5000. The radio’s IF was sampled by an SDR-14 and displayed with SpectraVue. Tracking of the probe was with PstRotator’s DSN feature.
Figure 1 – Block diagram of N2QG’s X-band Amateur DSN station in June 2020.
I purchased a squeezed-tube depolarizer and super Kumar scalar ring from M0EYT (from uhf-satcom.com). KC2TDS terminated it with a waterjet-cut copper disk and added a probe which he carefully tuned with the VNA to get <20dB return loss in the 8.4 to 8.45GHz DSN band. I mounted this feed on my 3.5m dish and was able to receive Mars Express, MRO, and OSIRIS-ReX.
Despite carefully tweaking the feed, I’ve been unable to get the system mounted on the 3.5m dish to yield the signal levels that I’m expecting. I suspect surface accuracy is the culprit because the 3.5m dish behaves well at 1296 MHz, but the g/t is just not there at 8.45 GHz. I can receive Bepi-Colombo on the 1.2m dish with around 12 dB compared to 16dB on the 3.5m dish. However, M0EYT receives it at around 30dB on his 2.4m prime dish. In July I worked on decreasing the SNR of the downconverter, which improved signals some, but definitely not as much as I would have liked to receive from a 3.5m dish.
Towards the end of that month I returned the X-band feed and downconverter to the 1.2m offset dish because I needed the 3.5m dish to participate in the EME SSTV Moon Landing Party hosted by PI9CAM at Dwingeloo Radio-Observatory in the Netherlands.
The Hope Emirates Mars Mission (EMM), Mars 2020 Perseverance, and Tianwen-1 launched right around that time, and I’ve been able to track them all with the 1.2m dish.
Juno remains out of my reach, so I’m considering next steps to improve my system. I thought that this would be a good point in time to summarize my experience so far, and discuss out loud plans for the future in case that it helps someone else who is just getting started in Amateur DSN. CLICK HERE for my whitepaper “Amateur DSN Lessons Learned (so far…).”
This was a really difficult set to receive. Took 3 days worth of passes to receive all 16 images.
Impulse Dynamics, Inc., a company dedicated to improving the lives of people with heart failure, today announced its innovative CCM® therapy delivered by the Optimizer® system received an award from the R&D 100 Awards, a prestigious program honoring research and development pioneers and their revolutionary ideas in science and technology.
“Winning this award is a tremendous accomplishment for our company as it represents the recognition by fellow scientists and engineers for the enormous effort that has gone into developing this breakthrough technology. The therapy serves a huge unmet need for a very large group of heart failure patients who suffer every day with their symptoms, so it’s great for the technology to receive recognition at this level,” said David Prutchi, Ph.D., Chief Technology Officer and Executive Vice President at Impulse Dynamics. “I am pleased to congratulate all my colleagues that helped evolve what was initially an intriguing electrophysiological discovery into the transformational therapy that it is today.”
Impulse Dynamics’ website: www.impulse-dynamics.com