Author: SM0TGU

Senaste nytt frn ANS om Echo. Nu brjar ven S-sndaren at testas:

Some stations have noted the S testing and reported results, which is appreciated by the command team. The command team has been watching the temperature closely when the S Tx is on. Since it is only about 30 percent
efficient a lot of power must be dissipated in the transmitter and its enclosure. So far the temperature rise, while quite noticeable, has not been a problem.

AO-51 continues to spin and tumble at a relatively rapid rate. In one axis it s about 15 seconds per rev. While these rates are high they are not a problem for the satellite. They do create some fades on the downlink that
will go away once the tumble is damped out. Because of the high rates it is likely to take a while for that stable mode to be achieved. The torq rod has also not yet oriented the satellite to the earth s magnetic field.

A new section of the telemetry archive will be open soon with whole orbit data that has been collected by the command stations. Some of it is at a rate of 3 seconds between samples. That high sample rate data is what has
been being used to determine the spin and attitude. Once on-line that section of the site will be available for anyone to download archived telemetry.
http://coloradosatellite.com/echo

Approximately 2500 launch campaign pictures are now available for browsing on the web thanks to Chuck Green, N0ADI. The pictures can be viewed at
http://bach.as.arizona.edu/gallery/echo

There has been some speculation about modes for future experimenter Wednesday. While AO-51 is a very flexible and capable spacecraft, it is still too early to determine exactly what the final operational parameters will be on Wednesdays or during normal operations.

Klla: ANS 199

Senaste nytt om Echo AO-51:

The remainder of this week is expected to be spent loading some new code, testing the S downlink and the UHF B TX. Note that the S downlink when in digital mode will always be at 38k4 or higher. It is not capable of 9k6 due to limitations involved in making it work properly at speeds up to 76k8. We are pleased so far with the strength of the 2.45W S downlink. At times the UHF A TX (.150) will be off or at very low power. We will also be testing
transmitters at higher data rates. Listeners should not be surprised or alarmed if the UHF A TX is not on or if they are unable to copy it at 9k6 during some orbits.

The Command Team is carefully checking off the tests and measurements that are part of the commissioning process. They ask everyone to be patient and again, AO-51 is not yet open for use. Any transmissions aimed at AO-51 by
other than command stations will slow down the process and delay the day when it is open for all to use.

The coloradosatellite.com/echo web site was off line for a few hours Sunday and Monday due to a data center move. Stations wishing to upload telemetry should find it on line now.

[ANS thanks Jim, WD0E for the above information]

Klla: ANS 195

Nu heter AMSAT Echo AMSAT-OSCAR-51, AO-51:
—
AMSAT-NA President Robin Haighton, VE3FRH has asked me to handle issuance of OSCAR numbers, and has written me requesting an OSCAR number for the Echo satellite. Therefore, in response to his communication, I hereby issue Echo the number AMSAT-OSCAR-51 (AO-51) to this exciting new amateur radio spacecraft. Thus, AO-51 joins a long line of amateur radio satellites beginning with OSCAR-1 launched in December, 1961.

I wish to congratulate everyone involved in the design, construction, testing, preparing for launch, launching and commissioning of this latest Amateur Radio spacecraft.

I trust that amateurs all over the world will have an opportunity to avail themselves of the many features offered by AO-51. May AO-51 have a long and productive life.

Best wishes and 73,
William (Bill) Tynan, W3XO

Klla: ANS

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

Frn AMSAT-NAs hemsida:

During the last pass on 30 June 2004, the TX power was turned up to 3.1 W to assure a good downlink while continuing to load software. Unfortunately, the power could not be reset to a lower level before the pass ended. The BCR responded as expected and eventually turned off the transmitter. The transmitter will be left off for the remainder of the night to allow the batteries to fully recharge. During the 02 July morning passes over the US East Coast the transmitter will be turned on to gather telemetry and evaluate the situation.

If you have recorded any telemetry data please send both the Raw and Engineering CSV files to ke4azn@amsat.org.

[ANS thanks Jim, WD0E, for the above information]

Klla: AMSAT-NA

Frsta kontakten med Echo har nu gjorts. Telemtri har tagits emot p 435.150 MHz och sndaren lmnas p med en uteffekt p 0.3 watt. Det r allts fritt fram att lyssna!

First contact with Echo was at 1452 UTC on 29 June 2004. After collecting a bit of TLM the 435.150 MHz transmitter was turned off at 1500 UTC. The preliminary keps were observed to be pretty close. The first look at ECHO s
telemetry shows things are looking good. The battery was fully charged and the panels were delivering about 950 ma, which is fine. The panels were supporting the transmitter power adequately at about 2.3W output. The bird appears to be tumbling as expected. Internal temperatures are around
10C which is also as expected.

On the second pass the loading of software began and good progress was made. Telemetry continues to look very good. While fades clearly indicated we continue to tumble (as expected), at 2.2 Watts output we were able to make good bits without difficulty. Rather than turn the TX off at the end of that pass, based on a very good looking power system, the power was turned down to about 0.3 Watts.

The hour between passes was spent closely examining the captured telemetry and comparing it to pre-launch testing, as well as tweaking the keps a bit. At the start of the next pass the power will be turned back up and loading
the housekeeping software, a task which will continue on the evening passes tonight, will resume. The TX has been left on at about 0.3W.

If you record telemetry please send the CSV files to ke4azn@amsat.org.

Please do not transmit to Echo until checkout and commissioning has been completed and the satellite is made available for general use. Unexpected uplinks may cause delays in verifying the proper operation of ECHO and delay
the opening of the transponders to general use.
[ANS thanks Jim, WD0E, for the above information]

Klla: ANS