Cutting-edge diy projects

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Cutting-edge diy projects

Monthly Archives: December 2019

1296 MHz Septum Feed Installed on 12 ft. Dish

Posted on by Posted in Amateur Radio N2QG, David, Radio Astronomy

1296 MHz septum feed for EME mounted on 12 ft dish. (c) 2019 N2QG David Prutchi, Ph.D.

I took advantage of the mild weather and holiday off time to install the 1296 MHz septum feed on the 12 ft dish.

Conditions are horrible right now for EME (the Moon is right next to the Sun), but I’m anyway still working on the power amplifier to make CW QSOs.  So far all I have been able to do is to optimize the feed’s position using Sun noise.  -3dB beamwidth is around 4 degrees, which is what I expected from this 3.5 m dish at 1.2 GHz.

The plastic box on the feed houses the RX isolation relay, LNA, filter, and cable driver.  The feed is mounted using a modified RF Hamdesign CLX05 bracket, which connects to the struts via a universal-mounting bracket designed by KC2TDS:

A C/Ku Polarotor Feed is mounted 7 degrees from prime focus to aid in calibrating the antenna’s rotor controller against geostationary-orbit satellites.  Here is the antenna pointing at the horizon, waiting for the next moonrise:

 

Visit to Satellogic’s Satellite Assembly Facility in Uruguay

Posted on by Posted in Amateur DSN, David, Travel
Visit to Satellogic's satellite assembly facility (c)2019 David Prutchi PhD www.prutchi.com

Left to right: Pedro Arzuaga, Assembled ÑuSat satellite, Jason Meyers, David Prutchi, and Julio Arzuaga at Satellogic’s assembly facility in Uruguay

Satellogic is an Argentinian company founded in 2010 specialized in Earth-observation satellites.  Satellogic began launching their Aleph-1 constellation of ÑuSat satellites in May 2016, and as of September 2019, have launched 5 satellites in that series (Fresco, Batata, MilaneSat, Ada, and Maryam).  We were invited to visit their satellite assembly facility in Zonamerica, near Montevideo, Uruguay.

Each ÑuSat weighs some 70 kgs (154 lbs) and are launched as secondary payloads on Chinese Long March 6 rockets. Once in orbit, these devices travel at 25,000 kph (15,500 mph) and take about 90 minutes to encircle Earth.  With the on-board telescope, these satellites yield images with one-meter-per-pixel resolution, which is impressive given the small size and reduced cost of the satellites.

The assembly facility, led by Eng. Fabricio Borsellino, is a truly remarkable example of how a high-tech manufacturing site should be run.   In a very short time Fabricio has managed to hire excellent personnel to conduct all of the activities required for the delicate process of assembling a satellite, and has been able to instate a culture of personal responsibility, ethics, and quality throughout the organization that will undoubtedly pay off as Satellogic’s demands for higher throughput grows.

Satellogic’s plan in the coming years is to maintain a constellation of 300 satellites.  Each satellite has a mission lifespan of around 3 years, so the assembly facility in Uruguay is gearing up to manufacture 100 satellites per year for ongoing maintenance and renewal of the constellation.

ÑuSat satellite of the Aleph-1 series designed and operated by Satellogic
Artist conception by Dererk – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=56277284