TOW Course Descriptions
Last updated: 010203
There are five types of courses to be offered at the Technical
Operations Workshop (TOW):
- Operations Workshops
are hands-on sessions with a maximum of about 5 participants
each. Each member of the class will have an opportunity
to participate actively in the training.
- Maintenance Workshops
are presentations to an audience of 10-20 people.
The classes will begin with instruction and demonstration, and
there may be some hands-on training. A large fraction of the time
is allowed for discussion and question/answer periods.
The subject matter includes a variety of topics.
Each class is taught by a team of experts who will handle
different aspects of the topic. The model for this type of workshop
is the successful RFI workshop at Wettzell following the IVS
are small groups that will discuss some seed
topic suggested at the start. The purpose is to gather feedback
and suggestions from the attendees. A moderator will help guide
the discussion and encourge contributions.
All attendees at the workshop will be scheduled for a discussion session.
are presentations to an audience of 20-60 people, depending
on the topic. The subject matter includes a variety of
special interest topics.
are intended for a general audience. The
subject matter includes topics that we believe are of interest to
everyone, or include announcements or information that everyone
should be aware of. All attendees at the workshop will be
scheduled for the seminars.
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Title: Experiment pre-checks
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
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
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
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
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
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.
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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
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
Title: Recorder maintenance
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
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
This workshop will cover receivers and basics of RF design.
Practical aspects of dealing with receiver maintenance will
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Title: Users suggest Field System improvements
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
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.
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Title: Using S2 Systems
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
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
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
Title: Intro to Linux
This course will cover the basics of using Linux (or any UNIX system) for
day-to-day housekeeping operations.
Title: Linux system administration
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
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
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
Plans for how to utilize the Mark IV decoder for diagnostics will
Title: Writing station-specific FS code
This course will cover useful information about how to implement
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
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
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
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
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
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
Title: Mark V System Development
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.
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Title: Tape Recorder Fundamentals
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
Title: Impact of operations on data analysis
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
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
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
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.
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Nancy R. Vandenberg
Last updated: February 21, 2001