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CODAR Newsletter Summer 06 - header
Links to the latest
SeaSonde software below:

Intel and PPC

Radial Software:

Combine Software:
Request download via email:

Advisories: - There is an indexing bug in the radial processing tools that may cause radials in different range cells to be placed on offset azimuthal spokes if the radial resolution in the Header.txt does not match the radial resolution of your measured antenna pattern file.  For instance, if you set the radial processing to use 5 degree resolution, but your antenna pattern resolution is 1 degree, you may see radials in range cell 3 fall on the 15, 20, 25, etc. spokes, but in range cell 4 they may fall on 16, 21, 26, etc. spokes.  Radial directions will be off at most by 1/2 of your radial resolution.  This does not affect processing with ideal antenna patterns.  A fix will be available soon.

- A bug has been found in the Wave Model tools released in late 2005. Calculated "WaveDirection" measurements are incorrect. The tool has been corrected in Intel/PPCRelease5 only. Cross Spectra can be re-processed with the new tools to obtainthe correct measurements.

Note: CODAR Ocean Sensors, Ltd. no longer supports Mac OS 9 software. SeaSonde OS X software upgrades are free for all SeaSonde owners.
San Clemente Island, CA - SeaSonde
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Site Maintenance:
Tips for Effective
Data Management

- By Hector Aguilar
CODAR Ocean Sensors

A frequently overlooked issue with SeaSonde sites is the use of hard drive spacein the SeaSonde site computer. OS X, unlike previous Apple operating systems,no longer freezes up completely when the disk fills up but will protect itselffrom grievous harm due to lack of processing space. To prevent unnecessary lossof data, it is highly recommended to budget your drive space. The following isrecommended:

1) Use a large external drive for archival purposes.
a) Using an external drive allows for a duplicate of the data on the SeaSondemain drive to be made immediately, thus protecting the data from any chance ofcomputer failure.
b) A longer history of archived data can be maintained on site.
c) An external archive drive setup allows for a quick swap out with a fresh externaldrive that immediately increases storage space without having a long downloadtime to deal with.

2) Archivalist can help you budget your hard drive space efficientlyand easily.With Archivalist you can:
a) Archive data from real-time output folders to the external drive and computerhard drive simultaneously.
b) Set limits on the number of archive folders kept on the computer hard driveso that older folders are deleted
before the maximum capacity of the hard disk is reached.
c) Decide which types of data files to archive and how long to keep them.

Here is a table that lists the average size of common files found on a SeaSonde.Note: these are for a 5 MHz system. Whether they are archived in weekly or monthlyfolders in the Archives depends on the individual Archivalist settings.

Type Single File size File Unit AverageDrive Space Used
CSS files (CSS) 2.5 MB 30 minutes 2.1GB  per month
Wave (WVLM) 1.5 MB monthly 200KB-1MB per month
Radial files (LLUV) 4 to 240 KB hourly 11-30 MB per week (x2)
Diagnostic files (STAT) ~ 300 KB weekly x2 1.3- .4 MB per month

3) The occasional 'spring cleaning' of the hard disk is alsoa good habit to develop in maintaining a well performing computer. Decide onan external drive swap trip to the remote site every three to six months dependingon the rate at which data is being stored on the site. Two or more external drivescan be employed for sites that are more difficult or cost prohibitive to visitor if you just prefer to have redundancy.

4) Running the Disk Utility (in the /Applications/Utilities/folder) at regular intervals is also recommended. With Disk Utility you can verifythe disk integrity, de-fragment the hard disk and verify system permissions.Although hard drive failures are not common, they do occur and Disk Utility canhelp as an early warning or prevention tool to reduce downtime.By taking thetime to perform these steps the operator can be assured of a healthy computerand good management onthe radial data being generated by SeaSonde.
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Property Lists:
Understanding SeaSonde
Suite Settings

- By Hector Aguilar

As many SeaSonde users may have noticed, CODAR has recently shifted away fromusing plain text files to using property lists, an xml file format, for its preferencefiles. Within these files, users will find the information used to control theoperation of most of the Radial and Combine Tools Suite programs. There are somegood reasons to do this:

1) Use of key/values pairs
Property lists are arranged by property keys and corresponding values. These values can be boolean (yes or no) or alpha numeric values. This makes property lists easy to use, the values are easily modifiable and can be kept track of with little ambiguity.

2) No order required in the property file
Our original ASCII text preference files had to be placed in a specific order.This is no longer the case. Properties can be in any order as long as each keyremains with its corresponding value. This has allowed for centralization ofproperty lists. The latest SeaSonde Suites put most of the lists in the RadialConfigor CombineConfig folders for ease of modification. While some properties arestill using text lists, further updates will eventually make all preferencesinto property lists.

3) Developer tools available
SeaSonde developers can use built-in tools available on any computer runningOS X. Links for PERL developers wanting to utilize property lists are listedat the end of the article. You can also use the 'defaults' command to modifyindividual property values in a property list without editing the file directly.This prevents corruption of the data format. More information on this commandcan be obtained by executing a 'man defaults' command in a terminal bash shellwindow.

4) Finally, property lists can be modified on the fly. This allows for SeaSonde applications to implement any new settings on the next data iteration without having to restart the application.
Here is an example of the SeaSonde Acquisition plist seen when opened with atext tool:

Unless one is familiar with XML code, reading a property list can be difficultto understand and time consuming to read using a text editor. In order to makethings easier, we recommend the third party program, Pref Setter. Pref Setterreadsthe plist XML code and displays them in an easy to read and edit format:

We strongly recommend that you read the format guides in the “Documents” folderinstalled on SeaSonde Radial and Central site computers and request that youdiscuss alternative settings with CODAR Support personnel before making changesto these lists.
Links for those interested in managing property lists using PERL:

Part 1:

Part 2:
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Tech's Corner
It’s About Time

- By Bruce Nyden
CODAR Ocean Sensors

This article addresses several important issues relating to time zone selection,computer clock adjustments and re-processing of data collected with differingtime zones. It was inspired in part by recent questions involving the constructionof larger networks using SeaSondes with differing time zones.

Advancements in HF radar technology over the last few decades have provided themeans to measure ocean surface currents on very large spatial and temporal scalesin near real-time. What initially started as a few isolated SeaSonde sites hasrapidly expanded in recent years. Networks have merged together to create a “bigpicture” view of coastal currents on near-continental scales. Nowhere isthis more evident then national network being developed for the continental U.S.

A Common Language for Time and Space

In order to construct a real-time surface current map at continental scales allof the contributing HF radar sites must share common temporal and spatial datums.The spatial datum used by SeaSonde software for all output data is the WGS 84spheroid. From the spatial aspect all SeaSonde users already have a common datumfor standardized mapping of current vectors. The temporal datum used for SeaSondeprocessing is user selectable. The choice of time zone (i.e. temporal datum)has created a few obstacles when agencies and academic institutions have attemptedtomerge their networks. A common time zone must first be agreed upon.

Merging SeaSonde networks facilitated the need for standardized temporal andspatial datums
Time Zones and Time Offsets

You’ve probably noted that new computers shipped from CODAR are configuredwith Reykjavik, Iceland as the time reference. Why Iceland and not Greenwich,England? There are three good reasons for this 1) Iceland is in the UTC (i.e.0 hrs offset, 2) Iceland does not observe “Summer Time” (the Englishequivalent of Daylight Savings Time) and 3) the Reykjavik zone is selectablein the Date/Time control panel map. The problem with “Summer Time” and “DaylightSavings Time” adjustments is that time is lost in Spring as clocks areset forward and time is duplicated in the Fall when clocks are set back. Anytime zone that changes its offset with respect to UTC is not a good choice tobegin with.

Reykjavik, Iceland is in the GMT zone and has no Daylight Savings Time

The time zone (temporal datum) of choice for large HF radar networks is UTC, Coordinated Universal Time. UTC is also the default used by GPS receivers and this makes it very easy to incorporate ancillary data into custom real-time displays. UTC and GMT (Greenwich Mean Time) are often used interchangeably. There are subtle technical differences but for our purposes we consider them the same.

For more information please contact:

Tech Note:
If you are using OS X 10.3 or higher there is a way to have data produced in the local time zone without the effects of daylight savings by manually setting the zone using the Mac’s built-in list and the Unix Terminal window (not all zones are shown on the map interface):
To set computer to a time zone from the list (for example GMT+8 for PST) use the following command:
/System/Library/CoreServices/RemoteManagement/ -settimezone Etc/GMT+8

This will keep the computer in PST without changing to savings time.

To see all of the time zones installed in your Mac’s database send the following command in the Terminal window:
/System/Library/CoreServices/RemoteManagement/ -listtimezones

Mac OS X uses the 'Zoneinfo' a.k.a. 'tz' database” which is updated every year.
Apple has just released a software update that includes recent changes in the dates that Daylight Savings Time is observed in the US. the most up-to-date time zone database, but advanced users can download and compile a new time zone database independent of the OS updates. 
For more information on this database and time zone management in general see:
Who tells the Mac what time it is?

Macs get their initial time and time zone settings from you, the user. Once connected to the Internet they can be configured to automatically check and reset the clock if necessary using a network timeserver. Timeserver clock adjustments are made with respect to the time zone and location that you have selected in the Date/Time pane of your System Preferences. One cautionary note, if the network timeserver you chose is unreliable, incorrect or has a flakey connection this can create more problems then just having an inaccurate computer clock. If the clock hiccups while trying to snynchronize itself to a time server it is possible that data acquisition will be interrupted or erroneous data will be produced.

GPS SHARES? equipped SeaSondes have their own built-in time servers. The GPS software will sync the Mac’s clock automatically whether or not the computer is connected to the Internet. Precision timing is crucial for SeaSondes sharing the same frequency. The SHARES? software periodically issues a command to check the AWG Controller for the current time. The AWGController is regimented by the incoming GPS time signals.
Lost Date and Time

If a Mac computer is disconnected from the power grid for too long or its memory back-up battery dies it will eventually lose its date, time and critical desktop settings. A few earlier Mac models would become so dead that even the “Restart After Power Failure” preference would fail to work when the power was finally restored. This required a site visit (to push the “power on” button) to re-start processing. One solution for sites with long and frequent power outages is to implement an intelligent UPS backup system (see our Summer newsletter). The intelligent UPS utilizes scripting and USB communications to shutdown a laptop Mac when a power loss is detected and the UPS has reached some pre-defined voltage. The same scripting periodically starts up the computer to conduct voltage checks on the power grid and UPS battery reserve. If the power has been restored, SeaSonde processing will resume.

If a Mac does power up after a power outage it still may have lost its date and time. When this happens, the date changes to the Mac’s default reference date which is less than the year 2000. SeaSonde software implements a “Lost the Date” script every time it starts up. If a date year earlier than 2000 is detected it will stop data acquisition until this is rectified. If it is a GPS SHARES? equipped SeaSonde system it will find the correct time again after the oscillator oven in the GPS module has warmed up and satellites have been re-acquired.
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Data Re-Processing:
Adjusting the Time Offset in Radial file

Suppose you decide to abandon your favorite local time zone to a join larger network consortium operating on a different time zone then yours and you want to convert your old archival data set to match the new format for consistency.
CODAR has just the tool for this job! It is called RadialAdjuster and is located in the folder /Codar/Seasonde/Apps/Tools/ in SeaSonde10 Releases 3, 4 and 5. To use it, simply launch the program, Pull down the File-> Preferences menu (shown below). Once you make the changes and save your preferences you can convert large batches of files by dragging and dropping a folder onto the RadialAdjuster icon. The converted files are output in the same directory as the originals.

Radial Adjuster Preferences

If your archival data contain vintage OS 9 Radsand Radz radials you can use the tool called CtfRadialer (also found in the “Tools” folder)to convert large batches of Rads/Radz radials to the newer Rdli/Rdlm (LLUV) format.The converted OS 9 files will contain all of the column headings of an LLUV filebut some of these columns will be empty. The calculation of quality informationwas implemented in the OS X radial processing tools. To recover this informationfrom OS 9 data, you need to re-process the CSS files with OS X software. Theconverted OS 9 radials can be used for combining even with the empty meta-datacolumns.

Pairing Radials by Time

SeaSonde10 Combine software requires that all Macs in the network be set to the same time zone. Files are combined based on the date, time and zone (offset from UTC) in the file header metadata and not the name stamp of the file. The offset is applied to the internal time and date stamp before the match up for combining. It is possible to have radials from two sites that are paired in time by the file name stamp but don’t combine when the Combine processing runs. To rule out the possibility that the two sites were set on different time zones, view the files with a text editor and see if the time zones and time offsets match (see sample file metadata in the boxed note below):
Tech Note:
SeaSonde radial and total vector files are ASCII files and can be read with any text editor. The time reference can be viewed in the first few lines of the file header.

Sample “Classic” Radial File Date/Time Stamp (Line 1):
10:00 AM Saturday, August 16, 2003 PST -1151094496

Sample “LLUV” Radial File Date/Time Stamp (Lines 1 -7):
%CTF: 1.00
%FileType: LLUV rdls "RadialMap"
%LLUVSpec: 1.03 2006 10 05
%Manufacturer: CODAR Ocean Sensors. SeaSonde
%Site: SEA1 ""
%TimeStamp: 2003 08 16 10 00 00
%TimeZone: "PST" -7.000 1

Sample Name Date/Time Stamp
At the present time there are no time zone metadata built into time series, range, CSQ, CSS or CSA files. Time adjustments have to be made at the radial level.

Be advised that OS 9 radials don’t have an offset reference to UTC (note Line 1 in the Rads example above). File matching and file conversion with OS 9 is based on the assumption that the three letter time zone codes are specific to one and only one zone. Recently we’ve found that there are duplicate zone codes that can cause confusion. CST for example can be Central Standard Time or China Standard Time. The time offsets from UTC for these two are clearly different.

In future releases of our Combining software we plan to implement an option that will allow all data to be acquired with reference to UTC for large scale networks but have an option to output total vectors in whatever time zone is desired for local scale displays.

In summary:
If you’re just setting up your SeaSonde for the first time, your best betis to use the UTC time zone for your processing.

Use a network timeserver to automatically set/correct your computer clock onlyif your SeaSonde is not equipped with GPS SHARES? and the timeserver has a reliableconnection

If you are unsure about what time or zone a radial or total represents, use atext editor to read the header metadata.
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Rules of the game:
- You must be able to provide a valid SeaSonde serial number (if asked) or beon our newsletter mailing list in order to play the game.
- Only one entry per person is allowed
- CODAR employees are not eligible
- One winner will be drawn from all of the correct responses submitted beforeMarch 31, 2007 at midnight.
Send your answer to (failureto use this email address will result in disqualification).

The Winter Issue prize will be ....
- A beautiful black zippered portfolio with the "CODAR" logo, seenat the right.

Here’s the question:
On the day of Superbowl XLI (2007) at exactly midnight GMT this mysterious interferencewas observed in the spectra of a 42MHz SeaSonde located at 373834N 1222812W.The interference lasted just under an hour and has never been observed since.

Question: What caused this?

A spectra from the event is shown below:

A spectra illustrating the SeaSonde's "normal mode" is shown below

If you have any questions,please email us: CODAR Quiz Winner (from our Fall 2006 Newsletter)

John Perez of Texas A & M was the winner of our Fall Newsletter Quiz. His name was drawn from a hat containing the names of the seven entrants with the correct answer.

The question was:
In what country is the city of Codar located?

The answer we were looking for was:
India. The City of Codar is located in the State of Arunachal Pradesh, India at 15.4N latitude and 74.05E longitude
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Announcing CODAR’s Spring 2007 SeaSonde Training Course

Our Spring Training Course will be held in Mountain View, California at our Corporate Offices located at 1914 Plymouth Street.

The four-day course will begin Tuesday 1 May at 9:30AM and end Friday 4 May at 3:00PM

There will be a "Happy Hour" gathering on Monday April 30 at 6 PM at The Tied House Restaurant in Mountain View.

Software sessions will focus on our new Intel/PowerPC SeaSonde 10 Release 5 software suite and the field sessions will be conducted at SeaSonde sites in the San Francisco Bay area.

Course Tuition:
Tuition is USD $750 per person, and includes course materials, 4 lunches, two dinners. New SeaSonde owners should contact for priority reservations.

For more information on the Spring Training Course, CLICK HERE

Crissy Feild SeaSonde installation
If you have any questions, please email us: CODAR Ocean Sensors logo

1914 Plymouth Street
Mountain View, CA 94043 USA
Phone: +1 (408) 773-8240
Fax: +1 (408) 773-0514
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