Cutting-edge diy projects

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Cutting-edge diy projects

Author Archives: David Prutchi

Strong Signals from Mars 2020 Perseverance and Tianwen-1

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Mars 2020 Perseverance received by N2QG (c)2020 David Prutchi PhD N2QG

Woke up in the middle of the night to take a look at the signal from Mars 2020 launched yesterday morning.  The signal exhibits a rotation Doppler component.

M0EYT let the Amateur DSN group know that Jon at JPL had loaded Tianwen-1’s ephemeris to Horizons, so I quickly added it to PstRotator:

PstRotator tracking Tianwen-1 (c)2020 David Prutchi PhD N2QG

I’d seen the reports on the strength of its x-band signal, but holy mackerel, it is huge even on my 1.2m offset dish at a range of 2.6 million km!

Cruise-phase signal from Tianwen-1 received by N2QG (c)2020 David Prutchi, PhD N2QGMy plan for this weekend is to move the dual-polarization VE4MA feed to the 3.5m dish to track the Mars-bound flotilla (Emirates Mars Mission, Mars 2020, and Tianwen-1).

 

 

Hope Mars Mission Spacecraft (EMM) Acquired Overnight

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Emirates Mars Mission HOPE MARS MISSION tracked by N2QG (c)2020 David Prutchi PhD

The Emirates Hope Mars Mission (EMM) Spacecraft launched yesterday from Japan using a Mitsubishi Heavy Industries H-IIA launcher.  I was able to acquire its signal as soon as it cleared my local horizon.  The screenshot above shows my house’s thermal noise fading away as the spacecraft gained elevation, to finally yield a clean signal past midnight (local time). Continue reading→

Tweaking EME for SSTV Moon Landing Party and DSN for Tracking UAE’s EMM

Posted on by Posted in Amateur DSN, Amateur Radio N2QG, David, Earth-Moon-Earth, Satellite hunting

1296 MHz was bustling with contest activity this morning.  Great signals made it easy to tweak RX and tracking in preparation of next weekend’s EME SSTV Moon Landing Party hosted by PI9CAM at Dwingeloo Radio-Observatory in the Netherlands.

In preparation for tracking the UAE’s Hope Mars Mission, I also tweaked my DSN X-band downconverter to improve S/N.  The latest configuration is as follows:

N2QG X-band DSN downconverter version 19Jul2020 (c) David Prutchi PhD N2QG

Click here for larger picture.

The EchoStar RV-750 “Umbrella” (Collapsible) 7.5ft TVRO Antenna

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EchoStar RV-750 Umbrella Collapsible Folding Portable Parabolic Satellite Dish Antenna (c)2020 David Prutchi PhD N2QG

I’ve been planning ahead to the day when I retire, my girls live on their own, and my wife and I can finally take the big-RV roadtrip that we’ve been talking about forever.  Not being one for sitting by a campfire, I’m always collecting equipment to take along, and some time ago my ongoing eBay® search for a collapsible parabolic antenna hit gold.  It was for an EchoSphere 7.5 ft TVRO folding dish in mint condition.  It even came with an extra (slightly damaged) reflector assembly to boot!  My plan is to build feeds for 1296 MHz EME and S-Band DSN.  Sadly, 10 GHz EME and X-band DSN are out of range for the reflector’s fabric.

The EchoStar RV-750 comes in a carry bag. It can be assembled and deployed in lessa than 10 minutes (c)2020 David Prutchi PhD N2QG

The EchoStar RV-750 comes in a carry bag. It can be assembled and deployed in lessa than 10 minutes (c)2020 David Prutchi PhD N2QG

Finding information on this dish has been much more difficult than I had anticipated.  I summarized my literature and experimental findings in a short write-up available at: The EchoStar RV-750 Antenna by N2QG Continue reading→

Diagnosing X-Band DSN and again QRV EME 1296 MHz

Posted on by Posted in Amateur DSN, Amateur Radio N2QG, David, Earth-Moon-Earth, Satellite hunting

BepiColombo spacecraft received by N2QG 5 July 2020 Amateur x-band DSN (c) David Prutchi PhD

I moved the X-band setup to the 1.2m offset dish to be able to characterize and diagnose.  The problem is that I’m unable to get the system mounted on the 3.5m dish to yield the signal levels that I’m expecting.  I’m suspecting surface accuracy 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 BepiColombo 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.

Is it time for my garden to grow a new large solid dish?

Strong Signal from OSIRIS-REx Received at 8445.538 MHz

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OSIRIS-REx spacecraft received by N2QG (c)2020 David Prutchi PhD

One more beautiful trophy for this weekend: Great signal received from the OSIRIS-REx spacecraft after M0EYT kindly told me how to find its ephemeris (hint: it’s orbiting around asteroid Bennu).
OSIRIS-REx is NASA’s first asteroid sampling spacecraft. It’s currently orbiting asteroid Bennu on its 7-year mission to return a pristine sample from that asteroid.

N2QG DSN X-Band Downconverter

Posted on by Posted in Amateur DSN, Amateur Radio N2QG, David, Satellite hunting

N2QG DSN X-Band Downconverter (c)2020 David Prutchi PhD

CLICK HERE for high-resolution image.

Lately I’ve been asked about the downconverter that I built to receive X-band DSN signals.  Because of time limitations, I took some shortcuts, namely using commercial connectorized modules and a high-stability signal generator with integrated mixer (DS Instruments MX12000 Integrated-LO Mixer) instead of designing the circuit from scratch.  The cost of the unit is thus relatively high, but it was either that or not being able to receive X-band spacecraft at all in the foreseeable future.

We tested the downconverter (without LNA) at MUD2019, and measured a 4.58 dB noise figure and a downconversion gain of 24.4 dB.