SDR Version 4.1 Documentation

Last Updated: 07/28/2002

Download Version 4.1 here or here

A Windows based version of SDR is now available. See WinSDR for more information. 

These help pages can also be viewed in Adobe Acrobat PDF Format


The Seismic Data Recorder (SDR) program collects data from up to 8 channels at 100, 50, 25, 10 or 5 samples per second (SPS) or up to 4 channels at 200 SPS. All data is saved to disk so you can replay the data (see the Replay command) and produce PSN format files that WinQuake can view. The data is stored in a file for each channel with the file extension of CHANx.jjj where x = 1 to 4 and jjj = Julian day or 001 to 365. Each day, starting at midnight UTC time, a new record file will be created. Old record files will be purged from your system depending on a setting under the F6 settings. You must make sure you have enough disk space available for the number of channels you have, and, the number of days of data you want to save. Each channel will produce about 6 megabytes per day at 50 SPS or ~12 megs at 100 SPS.

SDR will also automatically save PSN format files if one or more channels go past a pre-determined Alarm Point or STA/LTA (Short Term Averaging / Long Term Averaging) threshold point set for each channel (ALT-1 to ALT-8 keys). When an alarm is triggered SDR will wait about 3 minute after the alarm stops and then create a event file starting about 2 minutes before the trigger time, and ending about 3 minutes after the alarm stops. If you are going to be recording teleseismic events you will need to wait for all of the phases or waves to come in. This can take up to 1 hour or more depending on the size of the event. To produce one event file for the event you would then Replay the data (R key) and go to the start of the event. You then Save (S key) the event to a PSN format file. This release of SDR saves event file data in the new PSN Type 4 format.

SDR Document Links:

Upgrade Information:

If you are running an older version of SDR you must replay and extract any event files before upgrading. This version of SDR will not read the daily record files produced by old version of SDR, and it will overwrite the current days record file if present.


If you are having problems getting SDR to run on your system, and, if your system has the newer PCI type slots on the motherboard, you must do the following.

In your BIOS settings enable the interrupt you will be using (default = 5) for ISA buss usage. Please refer to you motherboard manual for more information on how to get into the BIOS settings pages and how to enable the ISA interrupt.

What's New:

Version 4.1:

When a channel goes into a triggered or alarm state the trace will change color.

Version 4.0:

Release from beta 6/15/01. Changes from 4.3b:

Increased the precision of the channel latitude, longitude and sensitivity fields.

Added Datalogger ID string. See PSN Type 4 variable header ID 7.

Added support for PSN 12/16 Rev 3 A/D board.    

Version 4.0b:      

Support for PSN Type 4 format.

STA/LTA event triggering.

Eight channels can now be recorded at 100 SPS or less. 

Up to four channels can now be recorded at 200 SPS.

Version 4.1b:

Fixed a bug with the length of the event file when replaying data.

Version 4.2b:

Recompiled code for 386 or higher CPU types. This made the sdr.exe file smaller and the program should run faster. 

Version 4.3b:

Removed support for the PC-Labs A/D board. Added network affiliation and component name fields to the channel settings screen. Fixed a problem around memory allocation for 200 SPS.  

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Larry Cochrane -