2017 SARA Conference Presentation Abstracts
Author: Dave Fields
Title: Radio Astronomy and Light-Sail Research with Small Satellite Support
Small Satellites are defined as 3X cubesats and smaller. They can potentially be deployed in the LEO zone or far above, and provide platforms for economically testing concepts and performing research
tasks. Microelectronic and highly redundant radiation-hardened circuitry, advanced communication protocols, and the possibility for maneuvering via interactions with gravitational, as well as static and dynamic electromagnetic fields/fluxes provide a wide trade space of possibilities. In particular, we consider HELIOS (Heliospheric Earth-Lagrangian Interception of Sunlight) and Breakthrough Starshot. These important frontier projects rely on light-propelled sails, a novel area of study with a relatively
unexplored research landscape. Second, we consider the ability to measure the RF spectrum with remote space-based receivers. For example, the VLF radio flux, an energetic EM window outside
our ionosphere due to radio emissions from the sun and four local planets, is inaccessible from earth-based observatories. We discuss how to address these two challenges, the cost and complexity of small satellite launches, and telemetry considerations. Requirements for meeting these challenges are (1) developing sensitive ground stations, dedicated to contributing to scientific and technical projects, and (2) launching bespoke satellites to study light-sail concepts and characterize the in-space VLF spectrum.
Author: Dale Gary
Title: Observing the Radio Sun Across Seven Decades (200 kHz to 200 GHz and 70 years)
The discovery of radio emission from the Sun dates back more than 7 decades, to the discovery by Hey (1942) of radio “jamming” of World War II radars by radio outbursts from the Sun. Likewise, with steady advances up to the present day, we can now observe the Sun and solar activity over more than 7 decades in frequency, from ~30 kHz to ~300 GHz. I will employ both of these senses of the term to survey what we have learned over 7 decades of history about the characteristics of the Sun as seen over 7 decades of frequency. It is remarkable that this entire frequency range is called “radio frequencies,” since an equivalent 7 decades from 300 GHz to 3×1018 Hz spans all of THz, infrared, visible light, ultraviolet, extreme ultraviolet, and soft X-rays. Therefore, it will be no surprise that the Sun’s appearance and characteristics change dramatically over this vast range of frequencies. Nevertheless, this otherwise complex subject can be organized and greatly simplified by considering three characteristic frequencies of ionized plasmas as applied to the Sun, the plasma frequency, the gyrofrequency, and the frequency at which the free-free optical depth is unity. We will see how these frequencies compete for dominance and govern what can be seen and studied with modern solar radio telescopes that operate over this 7-decade frequency range.
Author: Richard Russel
Title: The Use of Monte-Carlo Analysis to Evaluate Radio Astronomy Source Detection
The Plishner Radio Astronomy and Space Science Center is operated by the Deep Space Exploration Society based out of Colorado Springs, Colorado. Monte-Carlo analysis uses multiple iterations to evaluate all ranges of variables in a systems performance. The 1420 MHz receiving system for the Plishner Radio Astronomy and Space Science Center 60-foot dish system was evaluated. This analysis shows the antenna and receiving system component performance ranges and the effect of each against the expected signal source detection capability.
Author: Richard Russel
Title: Total Solar Eclipse Sudden Ionospheric Disturbance (SID) Monitor Signal Predictions using Sunrise and Sunset Measured Historic Data
The Plishner Radio Astronomy and Space Science Center is operated by the Deep Space Exploration Society based out of Colorado Springs, Colorado. The Sudden Ionospheric Disturbance (SID) monitor shows significant variations at sunrise and sunset. The Northern Hemisphere will experience a total solar eclipse on August 21, 2017. This paper characterizes the transition characteristics of the SID data and uses this data to predict the effects of the total solar eclipse will have on the SID system signal levels.
Authors: W. Liles1, L. Lukes2, J. Nelson2, K. Kerby-Patel3
Title: VLF/LF and the 2017 Total Solar Eclipse
The very first use of the solar eclipse to study the ionosphere was done in 1912 at a wavelength of
5,500 meters. Since that time, multiple studies have been down at VLF and LF frequencies. But most
of these studies were performed by a single receive site with a single transmit location during a single
eclipse. Thus making it very hard to compare data from separate collections.
We address the historical collection efforts and what has been learned of the sun’s role in the
ionosphere, as great strides were made including addressing the issue of the role of neutral corpuscular
particles ionizing the ionosphere. The questions raised by these studies will also be addressed.
A planned crowdsource effort will then be described that will attempt to address and answer the
questions raised by having multiple receivers all reporting on the same VLF/LF stations.
There are two approaches to the crowdsource collection. One is to use the SuperSID network that is
already reporting on changes in propagation of VLF stations. The other effort uses a receiver and
antenna based upon a design by Tom Hagen, NE9Y, and a smart phone as a software defined radio.
Both approaches will be detailed.
1) Independent Consultant
2) George Mason University
3) University of Massachusetts Boston
Author: Skip Crilly
Title: Pulsar Observations at 1400 MHz using the Forty Foot Telescope at the Green Bank Observatory
Abstract: Pulsar observations at 1400 MHz are difficult to make with small apertures due to lowering flux at increasing frequency. This paper describes a pulsar back-end measurement system
that was designed to be used with the Forty Foot Telescope at the Green Bank Observatory. The system observes pulsars using the overlap and add method, with known pulsar period. Pulsar observations and the pulsar measurement system will be described, with information provided so that others may
replicate the measurement system at reasonably low cost.
Authors: Dr. J. Wayne McCain, Collin R. McCain
Title: Amateur Radio Meteor Scatter Experiments (ARMSE) – A Brief Report
Meteor scatter is an interesting and potentially useful phenomenon that occurs when radio signals (generally 50 MHz and above) are reflected back to Earth from the ionized trail produced when a piece of space-borne material (e.g. broken up asteroid, or even ‘space debris’) enters the atmosphere. These brief ionized trails, lasting only a matter of seconds, can be monitored via the reflected signals and even used for communications purposes. The normal sources for the reflected RF waves are high-powered TV transmitters, but since these are becoming scarce due to conversion to digital TV, other transmission sources are being explored. This paper gives a brief overview of experiments conducted by several SARA members in late July and early August 2016 wherein low power (less than 1000 W ERP) amateur radio transmissions on 6 m were used in attempts to generate the meteor scatter reflected RF wave phenomenon. Participants included the authors, Jay Wilson, Chip Sufitch, Nick Pugh, David Fields, Adrian Howell, and others. While very little if any success was reported, the effort did pave the way for additional experiments in this area and pointed to the possible option of using strategically-placed amateur radio transmitter sources to further investigate and capitalize on this unique RF propagation mode.
Author: Dr. Chuck Higgins
Radio Jove Citizen Science for the 2017 Solar Eclipse
On August 21, 2017, the Great American Eclipse of 2017 will take place. Radio Jove is engaging citizen scientists during the 2017 solar eclipse by encouraging them to observe the solar eclipse with radio telescopes. We will enlist and train observers from across the US to help with deployment of the telescopes at different locations along the eclipse path of totality and at other locations receiving a partial eclipse. During the approximately 4-hour event (with totality lasting only ~2.5 min), radio observers will monitor the Sun for solar flares and radio events during the solar eclipse, as well as, observe the galactic radio background (GRB) before, during, and after the eclipse. The umbral and penumbral shadows will temporarily decrease the ionization levels of the terrestrial ionosphere, thus causing less absorption of the galactic radio background (GRB) over the eclipsed areas during daylight
hours. Thus, the total solar eclipse will offer a unique opportunity to study the response of the terrestrial
ionosphere, and perhaps determine the ionospheric (F-peak) electron densities. We will make most observations over a narrow frequency range centered on 20.1 MHz, and several advanced observers will operate spectrographs between 15-30 MHz. We will archive the data and make it available to the public and scientific community.
Authors: Professor J. Wayne McCain, Collin R. McCain
Title: Radio Astronomy CubeSats - Anthology
CubeSats – have been around for upwards of two decades now. The terminology refers to small,
light-weight, and usually ‘cube-shaped’ secondary payload satellites that take advantage of today’s
electronics to accomplish useful scientific research in space at much reduced cost and complexity. CubeSats are miniaturized satellites originally designed for use in conjunction with university educational projects and are typically 10 cm x 10 cm x 10 cm (4 inches x 4 inches x 4 inches) and approximately 1.3 kg (3 lbs).The CubeSat reference design was first proposed in 1999 by professors from California Polytechnic State University and Bob Twiggs of Stanford University (formerly Weber State (Utah)). Their goal was to enable graduate students to be able to design, build, test and operate in space a small spacecraft with capabilities similar to that of the very first spacecraft, Sputnik. The CubeSat, as initially proposed, did not set out to become a standard; rather, it became a standard over time. The first batch of CubeSats was launched in June 2003 on a Russian Eurockot vehicle. One launch provider, ULA (United Launch Alliance, Decatur, AL), has successfully placed over 100 into orbit by year’s end, 2016. Significant numbers of these small spacecraft have been dedicated to radio-astronomy-related research. This paper emphasizes and lists those cubesat missions (past-present-
near future) that have radio astronomy research objectives. It also formulates a basic specification for
a possible SARA-initiated cubesat radio astronomy mission (SARA-SAT1) and provides a list of potential mission objectives/scenarios for consideration.
Authors: Richard Flagg, James Brown
Title: An evaluation of the wire loop antenna described in the December 1989 issue of Sky and Telescope as an alternative to a Radio JOVE dual dipole array.
An article, “Jupiter on Your Shortwave”, written by David Rosenthal, was published in the December 1989 issue of Sky & Telescope. Rosenthal describes a small wire loop antenna designed by Bob Sickels (of SARA) who suggested using this antenna for observing the natural radio emissions from Jupiter. The small wire loop is similar to at least one form of the DDRR (Direct Driven Ring Radiator) antenna reportedly invented by Dr Boyer of Northrup in the 1950s. The article provides dimensional specifications for the construction of this antenna for use at 21 MHz.
The Radio Jove project recommends a dual dipole array for listening to Jupiter on 20.1 MHz but this antenna has the disadvantage of requiring quite a bit of space to set up. The small wire loop described in Sky and Telescope seems an attractive alternative to the much larger dual dipole array. But does it really work?
We have conducted side by side comparisons between what is often referred to as the DDRR antenna and the Jove dual dipole array. Following Sickels’ instructions, an antenna was constructed and compared with a standard Radio JOVE dual dipole phased array over the course of a year. Observations were made of both Solar and Jupiter events using single frequency receivers and SkyPipe software. The DDRR was also used with an SDRPlay RSP1 software defined radio to ascertain its viability as an antenna for spectrographic purposes.
The results of our tests and measurements will be presented as well as a conclusion as to the viability of the small wire loop antenna for reception of signals from Jupiter and the Sun.
Author: Jack Gelfand
Title: An Amateur Instrument for the Detection of the Cosmic Microwave Background
Astronomers detect the Cosmic Microwave Background as an extra noise equivalent to a black body radiating at a temperature of 2.73 K. They do this with an instrument called a microwave radiometer. A radiometer is a radio telescope calibrated with known temperature sources. A professional apparatus utilizes the temperature of liquid helium, 4.2K, to calibrate the temperature scale and cool the electronics. I have found that one can obtain a reasonable level of performance with inexpensive electronics operating at 10 GHz and a temperature calibration using liquid nitrogen. The configuration of my instrument is adapted from earth-based and balloon-borne instruments and has all of the essential elements of a professional apparatus.
Author: Dennis Farr
Title: Spectrum Analyzer and Sweep Generator on a Budget
Data obtained in radio work is only as good as the instruments gathering it. Having worked for many years in radio/radar communications, I have used premium top of the line spectrum analyzers and sweep generators. Now that I am retired, access to that level of equipment is no longer available to me.
When I started in amateur radio and radio astronomy, the desire to have accurate readings was instilled in me by my training and education. Checking on the prices of even modest spectrum analyzers quickly convinced me that they were pretty much out of my league. My interest in radio astronomy started when I read an article about the RTL-SDR dongle radio. For about $20 it seemed like I could at least get started for a very low cost. After putting together an LNA using amps and filters from Mini-Circuits, I wanted a way to determine the overall gain and bandwidth of the system. Another search on eBay turned up the TPI calibrated signal generator. This paper is about using these two pieces of hardware to enhance my radio astronomy experience.