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AO-51 status 11 juli

Mycket fakta om Echo AO-51 i denna notis. Fortfarande gller, snd ej till satelliten:

On the 06 July 2004, during the 0310 UTC pass, the SQRX was set to a VHF frequency and the antenna relay switched to the VHF whip. Once the various modulator/switch functions where set to the right configuration the SQRX
audio path proved to work fine. In an additional test of the SQRX the receiver was retuned to an L-band frequency and connected to the L-band antenna on the bottom of AO-51.

Testing has also been done on S-band using a frequency of 2401.200 MHz. The second 70cm transmitter has also been tested as well as the ability to command frequency changes to the transmitters should that be needed in the future. All transmitters have been confirmed to be operational.

Friday, 09 July 2004 the 38k4 digital downlink was enabled for the first time on the UHF A transmitter. Mike was able to copy packets at 38k4. Further testing will be done, and some WOD data will be downloaded at 38k4. The modulator settings for that mode will need to be tweaked as testing continues.

Mike, KE4AZN has taken some WOD data at 3 second intervals during daylight passes over his station to get a better look at the satellite s attitude. That data is being analyzed. When AO-51 is not in view of the command
stations, WOD at 30 second intervals is gathered continuously during the period from the time last time they see the satellite after a group of passes until their next AOS.

The EDAC count in Echo is not counting the actual number of physical memory errors, but the number of times the software detects a memory error while it is running. If the software loops through that section of memory a number
of times before the error is cleared, the EDAC count will increase by a large value. There is a routine that runs on a specific time interval to wash memory and clear any errors. Until that routine runs, if the program loops through that memory area, it will count an EDAC error.

With the file system now running, the downlink is going to show the BBS is open even though the BBS has NOT been made available for general use. Everyone is requested to please not transmit to ECHO until checkout and commissioning has been completed. Unexpected uplinks may cause delays in
verifying the proper operation of ECHO and delay the opening of the transponders to general use.

The commissioning and checkout activities are going very well. During this checkout period activities and plans are very dynamic and frequent mode and transmitter changes should be expected.

[ANS thanks Jim, WD0E and Mike, KE4AZN for the above information]

Klla: ANS 193

By SM0TGU

Webmaster and member of the AMSAT-SM steering group.

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