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21 April 2008
OSCAR-11 is now subject to eclipses which will continue until about 2019! During this period the satellite will probably transmit for a short time, less than an orbit, every 21 days. It is therefore unlikely that the satellite will be heard, except by accident when tuning around the beacon frequency.
RECEPTION REPORTS REQUESTED!
In the years ahead, it is possible that you may hear OSCAR-11, by accident, when tuning round the frequency. If you are able to record the satellite on audio tape or as a WAV file (not MP3), please do so, as it is unlikely that it will be heard on the next pass!
If you need to hear what the 145.826 Mhz. FM beacon should sound like, click here to hear a 10 second audio clip of the ASCII telemetry.
Please send reception reports to email@example.com (replace xxxxx by g3cwv) or post to amsat-bb. If you have a file, please let me know what you have, before sending it!
Click here to read the last news report for OSCAR-11.
Click to download the last ASCI telemetry received before the current eclipses started (10K). This includes an accurate time stamp, as it was received.
TELEMETRY ARCHIVE Updated to April 2008.
The software and information packages on this site are updated from time to time. Click here for full details.
The purpose of this page is to provide infomation about OSCAR-11, some real data which can be processed, and some software, which can be downloaded.
Most of the files are zipped, for quick download, and browsing at your leisure. If you have any comments, find any errors or require further information, please e-mail me ..... firstname.lastname@example.org (please replace the xx's by G3CWV ). If the files are zipped up, I don't see the contents very often, so if you do find anything wrong or missing it will help others, if you let me know.
To process the data you capture, download U2TM (U2TM.ZIP). You may like to try decoding the recent data described in the next section. There is also a lot of telemetry data in the archive which can be processed!
Click to download the last ASCII Telemetry received before the current eclipses started (10K).
Note this is real data, of a single pass. It will contain many errors, particularly at the beginning and end of the pass. If you use the program U2TM to decode the telemetry, best results are obtained by skipping the first frame. Enter R, and set the file pointer to 30000. This will decode the data in the middle of the file, where the quality is usually better than at the ends of the file.
The data files are date and type coded as follows -
Six figure date code + one or two letters representing data type.
Date = Year + month + day ... ie. YYMMDD
The date refers to the date when data was received, except in the cases of WOD, when it refers to the date of the survey.
T = Telemetry, W = WOD, S = Status, E = Engineering, U = SEU, B = Bulletin.
Sometimes there may be more than one ASCII WOD file for a given survey. These are identified by the addition of other letters to the file name. Incomplete ASCII WOD files will usually be replaced by a longer file, when the survey has finished..
A second letter P means packet, or binary data.
The raw data usually contains status blocks and other items, which help to identify the data. The WOD data is normally the concatenation of the data from several passes, and there may me some duplication. The processing software sorts it out, and ignores data of the wrong type!
The following file, which plays for about 10 seconds was recorded from a pass dated 14-February-1998.
ASCII Telemetry (81K).
S-band beacon (181K).
Joe KC6SZY has very kindly sent this recording of the 2401 MHz. beacon, which plays for about 20 seconds. You can hear the continuous carrier, and corrections for the Doppler shift as the 'STATION' program automatically follows the signal.
Joe uses an SSB converter, 76 cm dish, with 2.5 turn helical feed.
S-band beacon (156K).
This is a a 12 second extract from a file very kindly sent by Jim N5JDB. In this case manual correction of Doppler is used.
Jim uses modified Drake MDS converter, with DownEast preamp, and a 30 element Yagi antenna.
Modulation heard on S-band beacon (1169K).
This package contains two files of VERY low level modulation which has been observed by Colin VK5HI and Chris G4SDG. Colin uses a 77cm dish and Chris uses a 1.5 M dish with 2.5 turn helix feed. Both stations use SSB converters. Many thanks Colin & Chris.
Spectrogram of the Mode-S Beacon Mike WL9BQM has very kindly sent this spectrogram plot of the mode -S beacon. It was produced using the AF9Y FFTDSP42 spectrogram program. The signals were recorded at the end of a pass, when the Doppler effect was minimal. The signal strength can be seen on the extreme right og the graph.
Mike uses a six foot dish, Drake converter and preamplifier. The main receiver is a FT736 modified with a MuTec front-end.
This is a description of various hardware decoders for OSCAR-11. Includes use of telephone modems, home brew modems, TNCs, and emulated modems. As the drwawing make the file rather large, I have included the text only version as a separate file, for those who want to have a quick look. The text is the same in both versions.
U2TM This is a simple telemetry decoding program for the ASCII telemetry of OSCAR-11. The program is coded in BBC BASIC, and can be run on a standard PC by using the interpreter, which is included in the package. Both analogue and status telemetry may be displayed, and the program can easily be modified to suit individual requirements. File size 48.5K.
SATILL This is is a QBASIC program for predicting solar eclipses in a satellite's orbit. The eclipse calculations are based on James Miller's PLAN13 program. The package includes instructions,documentation, examples of input/output, spreadsheet application, James Miller's original code, and documention. There is also a BASIC interpreter enabling you to run the original PLAN13 code, if you wish to experiment! File size 196K.
SPIN A package of software, data, and documentation which enables the satellite's spin period to be determined from the ASCII telemetry. The program extracts the magnetometer telemetry, which may then be plotted manually, or by using SPLOT, or a spreadsheet. The period is determined by measuring the time between adjacent peaks or troughs of the X or Y axes telemetry. File size 137K.
U2ARY_TM A package of software, data, and brief documentation, which enables the satellite's spin period to be determined from the solar array telemetry. This is an alternative method to using the magnetometers, which have now failed.
The method is similar to that used in the above package (SPIN), and therefore U2ARY_TM only contains limited documentation. Users of U2ARY_TM should refer to the documentation in SPIN for detailed information. File size 83K.