1. Ongo 2-C Radio Telescope
Greg Bonett
Laura Janvrin
Project Advisor:
John Basart
Ali Abdelsalam
Osman Abdelsalam

2. Project Goal
Develop a working radio telescope for Iowa State, thus increasing research opportunities for students and faculty on campus, especially in the Physics and Astronomy Department

3. Concept Sketch
(carries radio signal)

4. System Block Diagram

5. Start of Year Status
Wiring issues on tower prevented operation of coaxial switch, noise source, and inhibited data collection
Limit Switch Relay board was not functioning properly, which prevented movement of the dish
Positioning software did not include tracking over time, and raster scan was inefficient
No documentation existed for limit switch relay board or terminal blocks within interface box

6. Deliverables
New Interface Box with permanent PCBs capable of reliable operation without frequent maintenance
Functional Tracking and Raster Scan software
Functioning positioning feedback, basic calibration routines, basic positioning correction
Limit Switch circuitry to stop motors when limits are reached
Complete, useful documentation

7. Operating Environment
Ambient temperatures range from -20ºF – 110ºF
Strong wind, snow, ice, and rain
Vulnerable to lightning

8. Project Risks
Dish hardware is custom built for our observatory, and cannot be replaced if broken.
Outdoor hardware can withstand temperature extremes, but there is a potential for ice buildup to prevent telescope operation.
Much of the existing hardware is old and prone to breaking down, much of the wiring is unreliable.
As this project has moved to a phased approach, critical information about the system could be lost if the new group and the returning group do not work together.

9. Risk Management
Maintenance must be performed each semester to make sure all of the telescope hardware is working.
Outdoor work on the telescope was all performed when the weather allowed.
The team has been replacing old cables and resealing weatherproof boxes to ensure reliability of equipment.
In both the fall and spring, returning members worked with new members to help share knowledge of the entire system.

10. System Components

11. Positioning Specifications
Reported dish position shall be accurate to within 0.1 degrees for both azimuth and elevation.
Azimuth and Elevation calibration shall be performed automatically or through a very simple (one or two step) process.
Continuous position updating shall allow tracking of objects and performing raster scans.

12. Positioning
This semester, the team focused on characterizing the positioning capabilities of the telescope and began calibrating the positioning.
Preliminary characterization and calibration was accomplished by aiming the dish at sun and comparing positioning feedback to the known coordinates of the sun.

13. Interface Box Specifications
Interface Box shall be properly labelled to allow ease of troubleshooting and maintenance.
Interface Box shall allow connection between the computer’s data acquisition card, and the receiver, limit switch circuit, coaxial switch actuation, and motor control box.
Interface Box circuitry shall be solid state components mounted on a printed circuit board.
Interface Box documentation shall include schematics for all circuits, as well as details for all wiring connections.

14. Interface Box – Limit Switch Circuitry
In the fall, a PCB layout was designed based on the current limit switch relay board, but re-examination this semester revealed missing connections.
A much simpler circuit was designed and tested that performs the required functions.
The new circuit was created using a PCB, which will improve reliability of the limit switch circuitry.

15. Interface Box – Positioning Circuit
Positioning circuit includes new Limit Switch circuit as well as a voltage divider circuit for positioning feedback

16. Interface Box – Positioning PCB Layout

17. Interface Box – Power Relay
An existing power relay circuit was modified and installed into the interface box, and software was modified to allow the relay to be tripped remotely.
With the relay installed, all components of the interface box can be controlled using a Remote Desktop connection.

18. Interface Box – Voltage Regulator PCB
Voltage Regulator circuit maintains a constant voltage in the Interface Box

19. Interface Box – Coax Switch Relay PCB
Coax Switch Relay circuit grounds the antenna when the switch is activated via software or physically.
It also powers the LNA, mixer, and noise source, and can switch on the receiver.

20. Interface Box – New Box
Old Interface Box
The new rack-mounted box will be neat and organized.
PCB boards will replace existing boards.
Ribbon cables and new connectors will be used to make the box reliable
New Interface Box

21. Software Specifications
Software shall support all system, component, and user interface specifications.
Software must possess an efficient raster scan function.
Software must be able to track celestial objects over time.
Software shall be organized according to semester and frequently backed up to prevent loss of work.
Software documentation shall allow future team members to pick up where previous team left off.

22. Software – Raster Scan
Old Raster Scan software in LabVIEW was modified to eliminate unnecessary and time-consuming motion of the telescope dish.

23. Software – Raster Scan User Interface

24. Software – Software Limits for Dish Movement
Only allow opposite voltage to pass to Motor Control Box when dish is 2 degrees from each physical limit

25. Software - Wiki
To facilitate the passing of knowledge from semester to semester, the team has implemented a Wiki.
Existing documentation was uploaded to the Wiki and indexed on the Wiki. This will also allow team members to search through all the documentation contained on the Wiki for needed information.
The wiki can be accessed at:

26. Complete System Specifications
System shall be operable remotely.
Software shall be comprehensible to astronomy students.
System equipment shall not require maintenance more than twice per semester.

27. System Maintenance
In the fall, the team replaced faulty cable and conduit going up to the dish.
A weather-proof seal was added to the feedhorn cap to prevent water from leaking in.
Feedhorn was checked in the spring for water.

28. Testing Areas
RF Section – All components relating to radio signals (feedhorn, amplifier, mixer, coaxial line)
Positioning Hardware – Detection equipment and motors
Positioning Software – Software programs used to position the dish for data acquisition
Interface Hardware – All circuitry used to connect the computer to the other system components

29. Testing Objectives Confirm basic operation of all components
Individual electrical components
RF Section
Positioning hardware
Positioning software
Interface hardware
Quantify system parameters
Measure RF losses
Determine positioning accuracy

30. Testing – RF Section
Individual RF components in the front-end box (mixer, LNA, noise source) were tested using a signal generator and spectrum analyzer
The entire signal path was tested using a signal generator at the observatory
Noise Source off

31. Testing - RF Section
Measured appropriate gain/loss through the entire system and through the front-end components

32. Testing – RF Section Component Gain/loss Low-noise amplifier 28 dB
Converter
19 dB
Noise source
10 dB

33. Testing - Positioning Hardware
Confirmed dish will move to known degree limits
Verified position detection hardware is accurate
After calibration, software (without software limits in place) shows 0° for minimum elevation, 86.5° for maximum elevation, etc.
Verified that position output is precise
Positioning variation is less than 0.05 degree if dish is not moving

34. Testing - Positioning Software
Confirmed software function by measuring DAQ output
Verified functionality by running positioning software
Input coordinates of known source (the sun)
Positioning software with correction placed dish in proper position
Verified tracking software functionality
Verified raster scan software functionality by performing raster scan of area of sky including the sun

35. Testing – Intensity Graph
Tested the intensity graphing capabilities of our system
Performed a manual scan across the sun and recorded the intensity every 10 ms
Amplitude of 385 corresponds to a solar flux value of Jansky

36. Testing - Interface Hardware
Performed continuity checks to ensure components are properly connected
Confirmed all software programs properly activate appropriate hardware relays
Verified input and output voltages meet component specifications

37. Work Descriptions
Green = Task Complete Yellow = Task In Progress

38. End of Semester Status We are testing the new Interface Box.
All three new PCBs in the Interface Box have been installed.
Raster Scan and Tracking software have been tested.
The RF system has been extensively tested and recommendations made for repairs.
All relevant interface box circuitry and positioning circuitry has been documented and labelled.

39. Earned Value Analysis
The old Interface box has been causing problems since its creation. The new box will reduce the amount of maintenance required.
The preliminary positioning calibration done this semester will give future teams a basis for more precise calibration and correction.
Documentation that has been created will improve future teams’ abilities to familiarize themselves with the project quickly and solve problems faster.

40. For the Next Team
Now that the basic software is available and working, unified user interface software should be written to make the system more user-friendly.
Pointing correction software can be written to further calibrate the positioning of the telescope.
The impedance of the feed horn should be matched to the line.
The raster scan software should be modified to do successive scans to reduce image noise.

41. Lessons Learned Conscious effort needs to be made to stay on schedule.
Proper documentation saves time and work in the long run.
It is impossible to plan all tasks at the beginning and work through them – problems will always arise and require adjustments and new planning.

42. Conclusions
The new Interface Box will be a great benefit to future teams in terms of reliability and ease of understanding.
The intensity of the sun has been successfully measured, and all components of the RF system have been characterized.
All of the software needed to run the telescope is complete, but improvements can still be made in terms of making one unified program.
At the end of this semester, the radio telescope system will be operational for future teams to add additional astronomy features.

43. Acknowledgements Dr. John Basart for work as advisor
Dr. Gregory Smith for feedback and providing funds for parts
Matt Nelson for help with PCB ordering
Jesse Griggs and Matt Clausman for Eagle software training
Ryan Cragg for help with making a lid for the Motor Control Box