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Author Archives: David Prutchi

12ft Dish Added to N2QG Antenna Farm

Posted on by Posted in Amateur Radio N2QG, David

This is the latest addition to my antenna farm.  It’s a 12 ft mesh parabolic antenna on a heavy-duty AZ/EL rotator.  My intention is to use it for 23cm and 3 cm EME, amateur DSN, as well as for next-generation amateur satellites/CubeSats and (hopefully) planetary probes.

Fortunately, my wife doesn’t mind my weird hobbies, my deed doesn’t have HOA restrictions regarding antennas, and New Jersey has a specific law that prohibits municipalities from adopting zoning ordinances that prohibit construction or use of antenna structures by federally licensed amateur radio operators (Act from Assembly No. 3641 of the State of New Jersey, 211th Legislature, introduced January 10, 2005)!

Thanks to the nice people at the municipal office, I was able to get a zoning/construction permit from my township with no issue.  The construction inspector already gave me approval on the footing, so now it’s time to load a feedhorn and start to QSO off the Moon.  The antenna is smaller than the maximum I requested in my permit, so I can still grow it by another ~3 ft in case I feel the need for a few more dBs.

Of course, I’m already thinking about my next antenna project.  My thought is a tall tower to support a very large 2m/70cm EME array along with a 6-element HF beam.  According to NJ Act 3641 I can put up a 70ft tower, and then place the antennas on top of that:

“No governing body shall adopt a zoning ordinance that prohibits or has the effect of prohibiting the construction, maintenance or use of an antenna and support structure therefor by a federally licensed amateur radio operator. Zoning ordinances may reasonably regulate the location and height of those antenna structures for the purposes of health, safety or aesthetics; provided, however, that those ordinances permit sufficient height of those antennas and support structures so as to reasonably accommodate amateur radio communications by federally licensed amateur radio operators.

Restrictions imposed on such antennas and support structures by ordinances shall constitute the minimum practicable regulation necessary to accomplish the legitimate purposes of the governing body enacting that ordinance. For purposes of this section, it is presumed that any ordinance that prohibits or has the effect of prohibiting any antenna support structure that is 70 feet or less in height above ground level, exclusive of any antenna upon the structure, is unreasonable. No federally licensed amateur radio operator, applying for permission to install or modify an amateur radio antenna or amateur radio antenna structure, shall be required to pay an application fee that is in excess of that which may be assessed for residential variances generally, nor shall such applicant be assessed any amounts for legal, technical, or other consultation or advisory costs incurred by the reviewing agency in evaluating the application submitted.”

 I love my wife and I love NJ!

Fun Weekend with KC2TDS Receiving SSTV from the ISS

Posted on by Posted in Amateur Radio N2QG

Jason Meyers (KC2TDS) and I (N2QG) had a fun weekend receiving SSTV from the ISS.  We tested many different radio/antenna configurations.  Along the way, we once again found out that Amazon “China-Special” connectors are worthless.  I’m trashing any connectors in my adapter box that are not real AMPs!

The real interesting finding from this weekend’s campaign was that the SDR-RTL (fancy version) does slightly better for this application than an AOR AR5000, ICOM IC-R7000, and Yaesu FT-736R!  We also tried the FunCube+ Pro against the SDR-RTL against weak terrestrial signals, and saw just a tiny bit extra SNR (the FunCube+ Pro has dedicated SAW filters).

Antennas used:  2MCP8A and log-periodic on Yaesu 5500 rotator, and eggbeater with Mirage preamp.

 

 

Power Injector for DiSEqC Horizon-2-Horizon Motor for ZGemma H7 FTA

Posted on by Posted in Amateur Radio N2QG

I’m currently rebuilding and expanding my space communication antennas with the intention of being QRV on 23cm EME, as well as being able to receive deep-space probes on the DSN X-band this coming spring.  My favorite way of calibrating the Az/El rotors is to use FTA geostationary satellites, and as a reference, I upgraded my C and Ku-band small-dish (120cm offset) with a heavy-duty horizon-to-horizon (HH, H2H) motor.

I found that my ZGemma H7 FTA receiver could not handle the current needed to operate the motor, so I built a simple power inserter just for the motor.  The 1uF non-polar capacitor provides a low-impedance path for the 22kHz DiSEqC signal to the motor, while at the same time the 10uH inductor isolates the RF from the LNB from entering the motor supply.  The 500uH inductor (rated for 4A DC minimum) isolates the 22kHz signal from being dampened by the filters in the power supply (an old IBM laptop power supply rated 16V @ 4.5A).

Clean schematic in pdf:  H2H Motor Power Inserter

Construction technique and enclosure are not critical, but the connection between the LNB and RECEIVER ports must be kept short.  My housing is the enclosure of an old DISH Network switch that I emptied out and modified to add a power connector compatible with my power supply.

This works like a charm!  The H2H motor now moves quickly and smoothly without shutting down the ZGemma’s tuners.

This is the current state of the Az/El VHF/UHF array and FTA dish at N2QG:

 

 

EmotiGlass Project Entry for The Hackaday Prize 2018

Posted on by Posted in Uncategorized

Jason Meyers and I submitted our project “EmotiGlass” as our entry in The Hackaday Prize 2018.

All augmented reality devices so far provide an interactive experience of the real-world environment that is enhanced by computer-generated perceptual information. In contrast, the EmotiGlass project explores ways in which a computer can modulate the user’s EMOTIONAL perception of reality. Our projects aims to develop the first “Modulated-Emotion Reality” device. EmotiGlass enables completely new applications in the field of augmented reality in which emotional biases can be manipulated by computer applications. Additionally, EmotiGlass has potential therapeutic applications as an aid to help control stress and anxiety.

To demonstrate and develop the EmotiGlass concept, a wearable prototype was designed and constructed. This open-source project was designed from the beginning to be easy to build using tools and materials widely available to makers and hobbyists. Full design files and detailed build instructions are available at the hackaday.io project page so that anyone can reproduce or extend the EmotiGlass design.

NOTE: The potential therapeutic applications for EmotiGlass have not been reviewed by FDA or any other regulatory agency.

A complete whitepaper is available at: EmotiGlass – v4.1 PUBLISHED –

 

New Book on Ultraviolet Photography

Posted on by Posted in David, Photography

Exploring Ultraviolet Photography book by David Prutchi PhD.

My new book “Exploring Ultraviolet Photography: Bee Vision, Forensic Imaging, and Other Near Ultraviolet Adventures with Your DSLR” is now available on Amazon for pre-order.

In this book, I will show you how to select equipment that allows you to capture otherworldly UV images. You’ll learn how to use filters that block visible light and prevent infrared light leaks and will discover how supplementing or overpowering sunlight with artificial UV light sources can help you create stronger images. You’ll also learn postprocessing techniques designed to enhance your UV photographs.

There is much to discover about the world as seen by bees, birds, and butterflies (and other creatures). I will take you into the wild to capture UV images that show how flowers advertise their nectar with beautiful markings to attract pollinating insects and birds. You’ll also discover how butterflies that look dull in visible light burst with intricate, iridescent patterns in UV.

Finally, you’ll learn about the scientific, medical, and forensic uses of ultraviolet photography.

From start to finish, this book will educate, inspire photographic creativity, and foster a better understanding of the UV world.

DOLPi DIY Polarimetric Camera Awarded 5th Place in 2015 Hackaday Prize

Posted on by Posted in David, Projects, Quantum Physics

David Prutcho PhD 5th place Hackaday prize winner

The DOLPi Raspberry Pi-based polarimetric cameras received 5th place in the 2015 Hackaday Prize. Winners for this year’s prizes were announced on stage at the Hackaday Superconference on November 14, 2015.

The DOLPi project involved the development and construction of two low-cost polarimetric camera types based on the Raspberry Pi 2. DOLPi-MECH (and its productized IR-VIS-UV version DOLPi-UI) is a filter-wheel-type camera capable of performing full Stokes analysis, while the electro-optic based DOLPi-EO camera performs full linear polarimetric analysis at higher frame rate. Complete Python code for polarimetric imaging is presented. Various applications for the cameras are described, especially their use for locating mines and unexploded ordinance in humanitarian demining operations.

CLICK HERE for a complete project description including detailed construction instructions and Python code in pdf format.

 

 

Possibly the Only Accessible Border Demarcation Pillar Placed under the Franco-British Boundary Agreement of 1920

Posted on by Posted in David, Shanni, Travel 1 Comment

 

Border marker pillar Syria Lebanon Palestine Israel 1920 David Prutchi PhD

My brother in-law, an Ob/Gyn physician and retired high-ranking Israeli Army officer is also a history scholar. He recently took us offroading in the Gallil to a rather unknown site that he found through his research on the Franco-British Boundary Agreement of 1920.  This agreement established the boundary between the Mandate of Palestine attributed to Great Britain, and the Mandate of Syria and the Lebanon, attributed to France.

We trekked to what may be the only accessible border demarcation pillar placed under the Franco-British Boundary Agreement of 1920. In 1922, 38 of these boundary markers were placed along the 49-mile (78 km) boundary. According to Newcombe-Paulet field survey of 1923, 71 boundary pillars were erected on the Syria/Lebanon border with Palestine. Most of these boundary pillars are either inside mine fields or have been removed by looters or people ignorant of their historical significance.

I haven’t been able to find even one picture of such a boundary pillar on the Internet, so my series of shots may be unique…  This picture, by the way is of the boundary marker at “Cairn 45”.  More pictures are available on my Flickr set.

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