Summary of 2011 SARA Southeastern Conference, 22 October

By Bill Seymour; Secretary, SARA
The SARA 2011 Southeastern Conference was held at the Tamke-Allan Observatory (TAO), Roane State College in Harriman, TN. SARA member Dr. David Fields, Physics Professor and Observatory Director was our host. He provided a science lecture room in a building adjacent to the telescope domes for the meeting. After a full day of demonstrations and presentations in the classroom, this made it convenient for the attendees to walk outside and participate in optical telescope viewing and watching the Orionids meteor shower on a beautiful moonless night.

Special thanks to David Fields, Bill and Melinda Lord, Linda Fippin, and others for the advance preparations made to ensure the success of this conference.
Nineteen persons attended the meeting and participated in the following events:

DEMONSTRATION---SpectraCyber/SDR 14 Observes Galaxy; by Carl Lyster, Engineer, Oak Ridge Y-12 National Security Complex; Observations of Doppler Frequency Shifts of -500 to +500 KHz in Neutral Hydrogen Clouds on the Galactic Rim of The Milky Way at 1420 MHz using a 6 ft Dish Antenna. Single Hydrogen peaks are best observed when galactic spiral arms are on the meridian overhead, such as 17 hrs Right Ascension.
WELCOME TO TAO AND ORIENTATION—Dr. David Fields
WELCOME TO SARA REGIONAL CONFERENCE; REGISTRATION AND MEMBERSHIP---Paul Oxley, SARA Vice-President (in absence of Bill Lord, who was unable to attend)

PRESENTATION---“Juno to Jupiter; How Radio Jove Might Participate” by Dr. Chuck Higgins, Professor, Middle Tennessee State University; NASA Radio Jove Team. The upcoming NASA JUNO Mission to Jupiter (named after the Roman Goddess who could see through clouds) was discussed. At a cost of $1.1 billion, Juno is due to launch in August, 2011 and loop back in a gravitational assist fly-by of Earth in October, 2013 before arriving at the Jupiter system in July 2016. There will be nine primary instruments on board, including UV Spectrometer, camera, electric/magnetic field antenna, particle detectors, aurora instruments , gravity experiment, magnetometer, and microwave radiometer. Professional scientists will be studying this data.

One goal of the mission is to study the interior structure and origins, evolution of the plant. If Jupiter is thought of as a brown dwarf-failed star, it may hold the key to the early solar system development and how planets formed, and this line of investigation is another goal. As a gaseous body, it rotates differentially—the cloud bands rotate separately. The magnetosphere has polar regions, aurora, and a plasma environment. An electrically conducting hydrogen layer in the interior of Jupiter generates the magnetic field which is tilted 10 degrees from the rotational axis. The core beneath is under tremendous pressure. Is it solid? Jupiter gets a lot of energy heat from the Sun and like the other gaseous planets Saturn and Neptune is generating more heat than the Sun is giving it. This is believed to be caused by gravitation contraction of the interior. Radio waves are generated by the interaction of the ions—charged particles-- generated by the volcanic moon Io with the magnetic field of Jupiter itself. According to data collected by The University of Florida over the last 50 years, the magnetic field is stable and has not changed. There are three main magnetic regions—A, B, and C—generated in part by the position of Io in its orbit. The radio waves generated are characterized as L Bursts (caused by spiraling charged particles and lasting a few seconds) and S Bursts (more intense milli- or microsecond bursts).

How can “citizen science” participation of amateurs increase our knowledge of the Jupiter-Io System, such as refining our knowledge of the emission mechanism, rotation period, and beam pattern propagation? One way is through long term monitoring such as that by amateur radio astronomers at the Goldstone Apple Valley Radio Telescope (GAVERT) , former NASA facility in California where teacher workshops are also held. Another way is through participation in the NASA Radio Jove Program where amateurs build receiver kits (designed by Dick Flagg) and construct dipole antennas to monitor Jupiter emissions at 20.1 MHz (15m). Jim Sky has developed special software, Radio Jupiter Pro and Radio Skypipe to use with this Jupiter monitoring hardware. Finally, the Long Wave Array (LWA) Spectrograph in Socorro, NM is just beginning to collect data that needs to be analyzed. Amateurs may be able to help with that. Also, old data from the Voyager spacecraft is currently being analyzed. In good discussions at the end of the presentation, it was suggested that a separate Radio Jove meeting be held at some point in the future.

DEMONSTRATION--- Monitoring of Naval Space Surveillance RADAR, by Carl Lyster. Carl tuned to the 216.98 MHz frequency where 100 transmitters generate a carrier-only signal (like cw) which is directed straight up in a RADAR curtain beam from a location near Kickapoo, TX. The purpose of the RADAR is to monitor parameters of objects orbiting the earth by calculating Doppler Shift. Carl received the signal on Upper Sideband (USB) with a 6-element “Quagi” antenna and down-converted the signal to 6m.

PRESENTATION---“Software Defined Radio: A Low Cost Introduction to Radio Astronomy” by Dr. Stan Kurtz, Professor, UNAM, Mexico, Morelia Campus; working professional radio astronomer and user of large radio telescopes around the world, including the Very Large Array (VLA) in New Mexico. Stan discussed various radio astronomy projects in Mexico, including the Large Millimeter Telescope, a 50 meter dish 120 miles East of Mexico City at 15,000 ft-- above most of the water vapor in the atmosphere which absorbs mm. waves. This is the biggest science project in Mexican history, with the government paying $140 million and UMass contributing $30 million. Instrumentation includes an ultra-wideband receiver 75 GHz to 111 GHz.

He also talked about the 140 MHz dipole array, the Mexican Array Radio Telescope with 4,096 antennas—a beam former with 1 degree by 1 degree beams. Internationally, Stan discussed the Expanded Very Large Array (EVLA) of 27 antennas. Mexico paid for the new electronics sub-systems in several of the antennas. The Very Large Baseline Array (VLBA) consists of 10 antennas, extending from Hawaii to the Caribbean. Mexico recently bought new disk drives and playback units for the VLBA, which helped increase its sensitivity by a factor of 5. The local CRYA Radio Astronomy program consists of two Haystack SRT Systems, mostly for high school and college undergraduate students.

Radio Jove is also used in high school and college programs. A wide range of radio astronomy topics are taught, including those for the first time in Mexico City High School in 2005. Distinguishing between Solar Storms and RFI, how many schools are detecting the signal? Data is taken from Radio Skypipe and published so that other users can see it. Parts are available in Mexico for a low cost (100 pesos; $8) 20 MHz receiver. There is a new project with Long Wavelength Array Antennas (10-88 MHz). USRP 1, a broadband Solar telescope has 12 folded dipole antennas. SARA member Marcus Leech wrote the graphical user interface. This is great for the Sun, not good for weak galactic sources. There is small gain and large beam-width. Even more ambitious future projects are in the works.

PRESENTATION---“A Breadboard Radio Astronomy Software Defined Receiver (RASDR)” by Paul Oxley, Electronics Engineer (Retired) and SARA Vice-President. Paul talked about off-the shelf components and the need to prove some concepts associated with the RASDR1 design path. He discussed the Texas Instruments ADC and Interface. A problem has been with the clock distribution board original concept—plug and play CMOS interfaces, hex inverter TI SN74ACO4 chip, and one input, two output inverters/drivers. There is an impedance match issue. Paul listed a bill of major materials. The problems with the concept are: 1) TCXO levels too low for CMOS input; Contacted Crystek to discuss solution; proposed pull-up/pull-down interface 2) Inverter output is too low for 50 ohm interface; 50 ohm match is needed for phase jitter; a solution developed. He showed a circuit which converts a clipped sine waveform to a CMOS waveform. He discussed the impedance match issue for the original circuit with 3.3 V (CMOS). The work in progress is: 1) To build a distribution board with pull-up 2) Test the distribution board 3) Port control software and firmware 4) Test with TI software 5) Write analysis software for TI data stream 6) Consider up-converter for lower frequencies.

PRESENTATION---“RASDR Prototype using Femtocell Technology” by Bogdan Vacaliuc, R and D Staff, Oak Ridge National Laboratory. For the RASDR0 design path, we propose using a 400 KHz to 2 GHz bandwidth, up to 28 MHz of sampling frequency rate, a $65 chip. Lime Micro is a company making a femtocell component for wireless infrastructure, and the RASDR0 design path is building a prototype software designed receiver based on this inexpensive component. We received an eval board for this chip two weeks ago. The challenges are to design the digital front end and couple this through a digital interface to the back end computer for subsequent analysis.

The front end of the receiver will be analog. After processing, the digital section will do significant processing and send digital signal streams to the PC via USB, or later, Ethernet. Zero to 30 dB in amplifier. The femtocell chip theoretically has ability to tune, determine sampling rate, and produce I and O output streams. Designing USB and Ethernet interfaces is a significant challenge since we want the device to have higher bandwidth and higher data rate to PC. The present proprietary evaluation board is expensive—fortunately we will use only one of these and with it we have obtained evaluation components, information, and detailed board design files.

Finally, the finished board will be produced by a commercial manufacturer. This will be an open design which can be purchased from SARA. The key to the final cost of the receiver is volume—to manufacture at least 30-35 units. Firmware will be interfaced from PC to receiver. Software will be on PC, and this will be open source. Summarizing the status of RASDR development: 1) Design is being based on Lime Microsystems Chip LM 6002D. It works from 400 MHz to 4GHz center frequency with up to 28 MHz bandwidth. We are now characterizing its behavior. 2) We are implementing interfaces to take digital data from receiver out to PC via USB 2.0 3) We are working to display evaluation on PC using Gnu radio software.

PRESENTATION---“The Lost Bands: Rediscovery and Importance” by Dr. David Fields. Detection and interpretation of VLF (very low frequency) electromagnetic radiation from extraterrestrial sources is a relatively unexplored radio astronomy band which is normally considered to be unavailable from the earth’s surface. However, under certain circumstances, it can be shown mathematically that VLF energy may penetrate the earth’s ionosphere—the ionosphere plasma frequency of 5-15 MHz day and 2-5 MHz night. David discussed cyclotron radiation in which electrons and ions go around magnetic field lines.

The Appleton-Hartner Equation describes how electromagnetic radiation interacts with the ionosphere. Ordinary waves are at ionosphere plasma frequency; extraordinary waves are well below plasma frequency. Consider the extraordinary wave. Consider the right hand circular polarization. In certain conditions, based on the direction of the earth’s magnetic field, these waves may penetrate the ionosphere with minimal absorption. Measurements by the U. S. Naval Research Laboratory using the Loft 1 satellite in 1961 demonstrated this. David discussed the spectrum of radio emission from Jupiter, based on the Voyager Space Probe. It is likely that Nikola Tesla in 1899 also received VLF signals through the ionosphere, in this case from Jupiter. The possibility of Tesla’s feat and how this was possible with his unique equipment was discussed. If indeed Tesla made this observation, then he was the first radio astronomer.

DEMONSTRATION---“Signal Hound USB Spectrum Analyzer” by Carl Lyster. Covers 1 Hz to 4.4 GHz and sells for around $900. Set a center frequency and set the span. It takes 20 seconds to cover the entire range. It has all of the normal controls for a spectrum analyzer. It does function as a receiver but does not have a well defined front end to demodulate the signal and discriminate it from noise. The vertical scale is calibrated in dBm. There is an internal 10 MHz oscillator, and it can accept an external oscillator. There is nothing available commercially that covers this frequency range for this low price.

PRESENTATION---“Using Radio Astronomy to Improve Variable Star Theory” by Robert Fritzius, Electrical Engineer (Retired) and Independent Researcher. Spectroscopic binaries are comprised of at least two stars orbiting one another but are too far away for us to resolve the individual stars. In optical astronomy, about ten percent of spectroscopic binaries vary in brightness, in a manner that is not yet understood, in step with their orbital periods. Amateur radio astronomers might do more studies of variable stars and other orbiting gravitationally-bound systems (using software defined radio for spectrum analysis) to look for time-varying radial velocity information.

Pulsars, which were first detected by radio astronomers in a 81-82 MHz window, have been studied for 40 years, and we still don’t know how they work. Computer modeling of one method of orbit-induced apparent variableness was given in this presentation. Keeping in mind the idea that some spectroscopic binaries are also variables, and that their variableness may somehow be related to their orbits, I ask, “Is the double-peaked Crab Pulsar a single neutron star (with two hot spots) spinning at 33 times a second, or is it comprised of, say two neutron stars orbiting one another at 33 times a second (each with its own orbit generated peak)?” Do variable stars have any detectable radio emission or absorption lines?

PRESENTATION---“RASDR Software in Linux” by Joe Teague, User Support Specialist, SAIC. Linux is a native environment for running Gnu radio. The libraries contained in Gnu radio were discussed. The Python file pulls data from a buffer. Python is an interpretative language. The capture of the data pipeline is the most important thing. A custom USB pipeline is needed to transfer to PCB. We are evaluating a synthetic data generator that we wrote under Linux, Windows, and the Mac OS, routing these data to a waterfall spectrum analyzer.

DEMONSTRATION---“Ten-Tec Wide Coverage Receiver Kit for Jove Application” by Carl Lyster. This is a dual conversion receiver covering 0.1 MHz to 30 MHz with Phase Locked Loop (PLL). The AGC would have to be disconnected for RA applications. There is a roofing filter and 1 W audio amplifier. It can be used in AM or SSB mode. The first IF frequency is 45 MHz. 5KHz step. Mode 1254. No surface mount components are used. The completed receiver has solid stability as opposed to the Radio Jove Receiver. The Ten-Tec kit sells for $198.

DEMONSTRATION---“USB Logic Analyzer/Oscilloscope” by Bogdan Vacaliuc. This is a low-cost bitscope, approximately $1000 ten years ago. A mixed signal oscilloscope connected to a display analysis computer, it also functions as a wave form generator. Having a logic analyzer coupled with an analog function should make it useful for RASDR development, and we are using it in this way for the RASDR. On a time sweep, there is a need to see an analog signal and digital data. This instrument samples at 40 MHz but has 100 MHz capability. There is successive sampling to reconstruct signal, but in this mode the display is not in real time. It has open software.

PRESENTATION/DEMONSTRATION---“RASDR Software in Windows” by Dr. David Fields. If the RASDR designs that we are building are to be adopted and used by SARA members, then they must interface with existing computers having different operating systems (OS). Most professional radio astronomers use Linux. Many computer-savvy amateurs use GNU (public license) radio tools which are also Linux-based. But most SARA members have only learned Windows. Since receiving the Lime Micro 6002 chip two weeks ago, we have been making initial checks and doing some circuit design for the RASDR0 design path.

Simultaneously, Marcus Leech, Bogdan Vacaliuc, Paul Oxley, Joe Teague, Stan Kurtz, and I have been concerned with moving toward software that should be useful on a range of computers. Here is an example of software running under Win XP on my cheap single-core laptop. A data generator program generates “synthetic” noise and signal data. These data are sent through a software data pipe to an analysis program built around GNU radio that uses a Python interpreter called by Win XP, and a waterfall plot of frequency spectrum versus time is displayed.

This should be compared to Joe’s demonstration of the same software under a fast six-core tower computer with Linux OS. The waterfall display is scrolling through time in both cases, but my laptop is obviously running much slower than the six core computer. Bogdan has the same program running under Mac OS at an intermediate speed, bit with better graphics.
The software work is just starting—this is a demonstration of the multi-OS concept. There are some differences in speed and graphical capabilities/quality between the various computer/OS implementations.

Overall impressions of the conference: Attendees expressed a very positive response to the meeting. The proceedings were well planned and organized. Technical content of the presentations and caliber of the speakers was very good. The conference site was on a beautiful but remote mountain top with a view of Watts Bar Lake below. The college facilities showed the wear of frequent use by students and community open house science events; shrinking college maintenance budgets were evident. Box lunches were catered on site, but an excellent dinner was enjoyed at the Gondolier restaurant eleven miles away. Most persons drove home at the end of the one day meeting. Those who came from a greater distance spent the night in local motels.

Photos from the conference can be viewed here http://www.flickr.com/photos/tnskynet/sets/72157628639365649/