TOW Course Descriptions

Last updated: 010203

There are five types of courses to be offered at the Technical Operations Workshop (TOW):

Back to top

Operations Workshops

Title: Experiment pre-checks
Teachers: Rich Strand
Description: We will practice all of the procedures and operational tests that should be performed before each experiment to insure that all of the equipment is set up and working properly, starting with drudging the schedule file and ending with pre-session e-mail to ops. Pointing will be covered in a separate workshop. This class is for people who use Mark IV, VLBA, or VLBA4 systems. The class will use the Westford Mark IV system, with appropriate notes made about differences for VLBA or VLBA4 systems.

Title: Experiment operations
Teacher: Rich Strand
Description: We will practice experiment operations from starting the schedule to the post-session operational report and recovery from power failures and other disasters that can occur during a session. The use of the "logpl" program for plotting data from the log during and after the experiment will be demonstrated. This class will be held at Westford.

Title: Recorder checkout
Teachers: Dan Smythe, Peter Bolis, Tom Buretta
Description: The Recorder Checkout Workshop focuses on tape recorder performance tests to detect subtle problems with the tape path. The purpose of this workshop is to demonstrate how a well-maintained recorder can perform, and how to optimize the tracking performance. It will cover the performance tests required to insure optimum reliable performance of a Mark IV, VLBA4, or VLBA tape recorder. These tests provide early warning of degrading performance, are useful for trouble-shooting problems, and improve understanding of tape recorder operation. Areas to be covered include tape tracking problems, high forward to reverse offsets, etc. It is a "how to test it" workshop.

Title: Automated pointing models and gain calibration using the FS
Teachers: Ed Himwich
Description: This course will cover basic support for pointing and gain calibration measurements in the FS. It will also include a demonstration of the "pdplt" program for analyzing pointing data. It will describe basic principals for configuring the mdlpo.ctl and ctlpo.ctl files that control the automated pointing data acquisition and delogging processes.

Title: Head calibration
Code: HdCal
Teachers: Dan Smythe, Peter Bolis, Tom Buretta
Description: We will run through a complete head calibration of a Mark IV tape recorder using a new, more efficient, Head Calibration Schedule similar to the one described in the Narrow Track Calibration manual in vol. 1 of the Field System manual, including pre-checks, error recovery, and post-checks.

Title: Head Stack replacement demonstration
Teachers: Dave Fields, Peter Bolis
Description: Most stations do not have the equipment or expertise to replace and condition new head stacks, especially for use with thin tape at high density. This demonstration will show you what happens when you send your head assembly to Haystack for head stack replacement.

Back to top

Maintenance Workshops

Title: RFI
Teachers: Brian Corey Tom Clark
Description: This workshop will discuss sources of interference that might affect VLBI observations. Particular emphasis will be placed on the levels and types of RFI that are most harmful to experiments. Also discussed will be techniques to identify RFI and (the limited range of) techniques to deal with it.

Title: Use of Spectrum Analyzer/FFT Analyzer in System Diagnosis
Teachers: Brian Corey, Tom Clark
Description: The spectrum analyzer is an extremely valuable instrument for checking analog system performance at RF, IF, and baseband frequencies, and for diagnosing problems. This course will review the fundamentals of spectrum measurement and its applications to VLBI system testing, with an emphasis on measurements of LO and phase calibration signals. Diagnostic testing of some typical problems will be demonstrated with a variety of spectrum analyzers, including low-frequency FFT and PC-based analyzers.

Title: Recorder maintenance
Teachers: Tom Buretta, Peter Bolis, Dave Fields
Description: This workshop will cover several of the recorder problems that may arise during recorder checkout procedures. Areas to be covered include head positioning and tape tracking problems, vacuum and loss of vacuum problems, causes of high forward to reverse offsets, speed instability, inability to move tape reliably at high speeds, blown fuses, how to tune up the capstan and reel servos, and answers to questions posed by workshop participants. It is a "how to fix it" workshop.

Title: Rack maintenance
Teachers: Tom Buretta, Dan Smythe, Rich Strand
Description: This workshop will cover checkout and maintenance aspects of the electronic racks. Areas to be covered include formatter checkout, VC/BBC performance, IF distributor checkout.

Title: Receiver design and maintenance
Teachers: Brian Corey Tom Clark
Description: This workshop will cover receivers and basics of RF design. Practical aspects of dealing with receiver maintenance will be covered.

Back to top


Title: Users suggest Field System improvements
Moderator: tbd
Description: This will consist of small group discussions, without Ed or Ray present, to brainstorm on new features and/or problems that need to be corrected. Everyone who has an opinion is encouraged to attend. The results of these sessions will be collected and then discussed at the final wrapup session.

Title: Users suggest operations improvements
Moderator: tbd
Description: This will consist of small group discussions to brainstorm on ways that field operations, interfaces, information exchange, or any other operational aspect could be improved. Everyone who has an opinion or a gripe is encouraged to attend. The results of these sessions will be collected and then discussed at the final wrapup session.

Back to top


Title: Using S2 Systems
Teacher: Georg Feil
Description: We will cover the unique operational aspects of using S2 systems. This course will be useful for people who have an S2 system or are expecting to get one

Title: K4 systems and Japanese VSI systems under development
Lecturer: Yasuhiro Koyama
Description: We will cover the unique operational aspects of using K4 systems. this course will be useful for people who have an K4 system or are expecting to get one. This lecture will also describe current development of VSI (VLBI Standard Interface) systems in Japan, including the revised giga-bit system.

Title: Correlator operations
Lecturers: Mike Titus Arno Mueskens Kerry Kingham
Description: This lecture/demo will summarize the stages a typical experiment passes through in its life cycle at the correlator and demonstrate the process of setting up production processing for a geodetic VLBI experiment. A laundry list of checks performed at various stages (especially setup) and their desired outcomes will be reviewed, along with descriptions of a few sample problems and how they are compensated for at processing time. Tips on how stations can help facilitate correlator setup and processing will also be covered.

Title: Intro to Linux
Lecturer: Ari Mujunen
Description: This course will cover the basics of using Linux (or any UNIX system) for day-to-day housekeeping operations.

Title: Linux system administration
Lecturer: Ari Mujunen
Description: This course will cover system configuration and management issues outside the normal course of experiment operations. The "fsadapt" program which can be used to simplify many of these tasks will be described.

Title: Pointing and single dish amplitude calibration
Lecturers: Alex Kraus
Description: In this course students will learn why accurate pointing corrections must be known for all parts of the sky to be observed, and how pointing errors affect geodetic and astronomical results. Students will learn how SEFD and system temperature measurements are related, how to check the focus, how to make SEFD measurements, how to measure a gain curve, which sources are best for the SEFD measurements, how weather can affect the measurements and results, and how the SEFD measurements are used for data analysis and scheduling. We will also discuss measurement equipment and how it may affect the results if care is not taken.

Title: Timing Systems
Lecturers: Tom Clark
Description: This presentation will discuss all the reasons for needing high-accuracy time and frequency in VLBI. This will include a discussion of all the "clocks" used in VLBI (Hydrogen Masers, GPS timing clocks, the clocks inside the Field System computer and the clock information needed by the correlators) and how they need to be tied together in order to guarantee successful VLBI measurements.

Title: Future FS support of the Mark IV decoder
Teachers: Ed Himwich, Roger Cappallo
Description: Plans for how to utilize the Mark IV decoder for diagnostics will be presented.

Title: Writing station-specific FS code
Lecturer: Ed Himwich
Description: This course will cover useful information about how to implement station specific code to work with the FS. This includes the programs "antcn" and "stqkr" primarily, but also "cheks", "sterp" and also how to add station-specific help pages. Select one of the sections of this course depending on your interest level, "beginning", "intermediate", or "advanced". There should be time to deal with some detailed problems at all levels. The upper levels are directed toward people who have already developed at least some station code. Prior experience with FORTRAN and C is needed to get much out of these courses. If you don't know FORTRAN and C, you may find that the "beginning" section provides a useful overview.

Title: Web access to data and documents
Lecturer: Nancy Vandenberg
Description: This course will introduce people to the resources available on the web for Field System documentation and geodetic experiment results. Access to FS documentation via the web will be demonstrated. The geodetic sessions web site will be demonstrated to show the station staff how to access analysis results. Other web sites of interest to VLBI will also be covered. A list of recommended bookmarks will be provided.

Title: Practical aspects of using thin tape
Teachers: Don Sousa, Bruce Thornton
Description: The special shipping and handling requirements of thin tapes will be covered. There will be a demonstration of the TRACK program and stations can get signed up to use the TRACK system for tracking tapes. We will discuss what to do with problems encountered with thin (and thick) tapes in the field. We will show what to look for when preparing the tape for prepass, what to do if a tape fails prepass, storage of tapes after prepass, what to do with broken tapes, and a demo on the correct procedure for tape splicing. This should assist both field station operators as well as correlator operators.

Title: Phase Calibration Basics
Lecturer: Brian Corey
Description: The phase calibration system is the primary means for ensuring that instrumental effects in the receiver and VLBI terminal do not corrupt the group delay measurements. This course will cover the basic concepts and hardware implementation of the calibration system, including the Mark IV cable measurement system. The nature and causes of spurious signals, which can degrade the calibration accuracy, will be described, along with means for detecting and eliminating them.

Title: Hydrogen maser monitoring and maintenance
Lecturer: Irv Diegel
Description: The intent of this presentation is to provide VLBI personnel with an overview of the hydrogen maser and its use in VLBI. The discussion will be generic so as to accommodate the different types of masers used throughout the VLBI network. Topics will include block diagram analysis of the physics and electronics systems as well as generalized operational procedures.
Title: The VLBI Standard Interface (VSI) Specification
Lecturer: Alan Whitney
Description: The international VLBI community has recently agreed on a standard hardware interface specification for VLBI data. This should greatly improve the interoperability of heterogeneous VLBI data systems over the next few years. The VSI specification will be described and illustrations of its usage given.
Title: Mark V System Development
Lecturer: Alan Whitney
Description: Work at Haystack Observatory is currently in progress to define the next-generation VLBI data systems. Recent studies indicate that magnetic discs are likely to overtake magnetic tape in cost and efficiency within the next 3 years or so for VLBI applications. Haystack Observatory is designing the Mark V system, based on magnetic-disc technology, and almost entirely made up of commercial-off-the-shelf (COTS) technology.

Back to top


Title: Tape Recorder Fundamentals
Lecturer: Dan Smythe
Description: This presentation is intended to help station personnel understand the fundamental details of tape recorder operation, at a basic level, with lots of visual aids. We will focus on an "ideal" recorder, one that passes all of the tape recorder performance tests with no errors, not even parity errors. Participants should leave this talk with a better understanding of the following topics: the difference between "head" and "track"; how each head lays down many tracks on the tape; why we need to calibrate the head stacks; what head stack calibration does and does not do; the relation between bandwidth, sample rate, fan-out and tape data rate; why we record at different speeds; what the bit synchronizer does; what an equalizer does; what happens if you play back a recording at the wrong speed; what we mean by recorded bit density; how to calculate bit density from sample rate and tape speed; why it is possible play back any recording at any speed, independent of the recording speed, if, and only if, you know how.

Title: Impact of operations on data analysis
Lecturer: Ed Himwich
Description: This course will describe the effect on geodetic data analysis of various problems during data acquisition. Problems such as clock breaks, bad tracks, parity errors, pointing errors, warm receivers, and late starts will be covered.
Title: Science Overview
Chopo Ma
Description: An overview of the scientific goals of geodetic and astrometric programs will be presented. Particular emphasis will be placed on reference frames which are the fundamental products of VLBI.

Title: CORE Program
Nancy Vandenberg Chopo Ma,
Description: Scientific goals of CORE. Results of 1997-2000 CORE-A/CORE-B/NEOS comparisons. Station performance standards. Coordination with EVN/TWG. Charts and tables of program evolution to the year 2004.

Title: Field System future plans
Speaker: Ed Himwich
Description: This presentation will cover the immediate and long-term plans for Field System development. The ongoing collaboration and cooperation on the Field System among various groups will be described.

Return to TOW Page

Further information: Nancy R. Vandenberg

Last updated: February 21, 2001