Radio Astronomy Projects
ă William Lonc
Astronomy and Physics Department
Saint Mary's University
william.lonc@stmarys.ca
2003
Published by
Radio-Sky
Publishing, P.M.B. 242
Ocean
radiosky@radiosky.com http:///www.radiosky.com
Table of Contents
Prefaces
1. Overview of Practical Experiments: 1
2. Right Ascension, Hour Angle, and Sidereal Time 3
From the Past: Jansky’s System: 5
3. Galactic Center at
5. Equivalent Black-body Temperature: 15
6. Calculating Required Bandwidth: 20
7. Interferometer symmetry: 23
8. Angular Dependence of Fringe-Spacing: 27
9. Analyzing an Interferogram: 31
10. Optimum Interferometer Spacing: 32
11. A Benefit of Phase-Switching: 35
12. Focal-point Heating: 36
13. Square-Law Detection: 38
14. Phase-Switched Interferometer: 40
15. Aligning an Antenna Along
the
16. Antenna Temperature: 44
17. Extracting Polarization Information. 51
19. Human Signal generator: 53
22. Intensity Interferometer: 61
1. Solar disturbances at 265 and 435 MHz: 64
2. Radio Telescope at 1296 MHz: 65
3. Conversion of a Marisat Antenna: 68
4. Detecting Meteors: 70
5. First Radio Quasars by an Amateur: 79
6. Simple TRF Receiver: 80
1. Beginner's Microwave Telescope at 12 GHz: 82
2. Beginner’s 4 GHz TVRO: 88
3. Very Small 4 GHz Telescope: 90
4. 4 GHz TRF Receiver: 95
5. 4 GHz Interferometer-- 4 m Baseline: 100
7. Solar radius at 4 GHz--28 m Baseline: 103
8. Solar radius at 4 GHz--4 m Baseline: 105
9. Small 10 GHz Radio Telescope: 108
10. The Moon at 11 GHz: 110
11. Computerized Observations at 11 GHz: 112
12. Radio Telescope at 12 GHz: 114
13. Small 12 GHz Demonstration Radio Telescope: 119
14. Backyard Radio Astronomy: 121
15. Multi-antenna Radio Telescope: 124
16. Home built Pyramidal Horn Antenna: 125
17. Home built Wave-guide to Coax Adapter: 131
18. Spiral Antenna Feeds: 134
19. Slot vs. Spiral Antenna Feeds: 138
20. Classroom Radio Telescope: 143
21. Microwave Spectrum Analyzer Basic Idea. 149
22. Plumber’s Delight Ku-band Interferometer: 150
23. All-Purpose Receiver Module: 153
1. Second Detector:
2. Digitizer from an X-Y recorder: 161
3. Temperature Effects: 164
4. Terrestrial Magnetic Fluctuations: 167
5. Height of the F2 Layer: 173
6. Hydrogen-line Spectrometer: 177
7: Data Logging: 179
8. VLF Observations: 180
9. Phased-array Antenna Projects: 181
10. Noise-adding Techniques: 182
Ku-band Telescope at
Chapter 5: Signal Processing Concepts
4. Fourier Transform--Why?:
196
5. Fourier Analysis--How?:
200
6. Fourier Synthesis--How?:
205
Chapter 6: Student Research Papers.
1. "The Galactic Center by Accident" by
Sherri Aker: 209
2. "The Sun's
Temperature at 5 cm" by Na Han Chan: 210
3. "Detecting the
Galactic Center at 70 cm" by Jennifer Hatt: 213
4. "Interferogram
Visibility Function for a 1/2 Degree Source", by S. W. Lee: 218
5. "Solar Temperature
at 7.5 cm" by George Lo: 219
6. "Verification of
Fringe Periodicity of a Two Element Radio Telescope", by Michael Swift:
227
A: Spectra of Major Observable Objects: 232
B:
C: Sidereal Time at 0h
D: Sundial corrections: 235
F: Historic Papers: 237
Preface to First Edition
This book is based on some
fifty articles originating from Saint Mary's University over the past few
years. Most of the articles were published in The Radio Observer, edited and published by the late Bob Sickles.
Others were published in Radio Astronomy
(a publication of the Society for Amateur Radio Astronomy*), the American Journal of Physics, and the Journal of the Royal Astronomical Society of
Canada. The book does not purport to be a text-book, but rather a
collection of 'projects' associated with radio astronomy at the undergraduate
or amateur level. Hence, the book is meant to be a resource for building and
using small non-professional radio telescopes, especially in the microwave part
of the spectrum.
A word
more on this point. When we first embarked on these projects, we assumed that it was
easier to begin in the VHF part of the spectrum. Although we were, in fact,
successful in making some observations at these wavelengths, it eventually
became evident that the relatively large bandwidths needed to obtain a
discernible signal using antennas that could easily fit on a flat roof of a
school building could not be achieved at VHF, mainly because there is too much
man-made emission in this part of the spectrum. Hence, we eventually moved to
microwaves, making use of surplus parabolic dishes and off-the-shelf satellite
TV components. However, if several hours are available for an observation, then
it is possible to use VHF or UHF, as exemplified in the papers by Sherri Aker
and Jennifer Hatt in Chapter 6.
Over the years, much
generous assistance was given by a fellow radio amateur, Mr. Bob Schultz,
VE1IF, and Physics Department Technician Richard Ives.
Contact the author at
voice (902) 420-5829; fax (902) 420-5141
email william.lonc@stmarys.ca
Web
search for “Lonc, William” or hit
http://apwww.stmarys.ca/~lonc/lonc.html
*SARA,
On the World Wide Web,
search under amateur radio astronomy for allied information.
This new edition contains a number of new topics, such as the
presentation of the Intensity Interferometer and an all-purpose module that
functions as an I.F. amplifier, Detector, d.c. Amplifier, and power source for
any SAT TV LNB that the observer may be using in any given experiment.
We have found the module to
be a very convenient instrument here at St. Mary’s. The Intensity Interferometer,
in our opinion, is a very promising approach in Amateur Radio Astronomy because
it uses off-the-shelf SAT TV modules and should enable the experimenter to
implement easily an interferometer
This new edition also
contains articles on detecting meteors using a VHF radio and measuring the
height of the F2 ionized layer – quite significant for radio astronomy – using
simple amateur radio equipment and techniques.
Enjoy!
William Lonc; Astronomy and Physics Department
Saint Mary's University,