Tag: Oscar 40

When the ALON/ALAT significantly alters, the M-blk gets modified and also posted here.There has been no significant change in ALON/ALAT from the last posting.

However, we are shortly about to raise ALAT quite a bit, followed by about 3 weeks of drifting past the sun. During this time, the squints will be poor, as will the solar angles. The transponders may be off for much of this time because of the poor conditions and to conserve power. At the end of that time, ALON will be ~335 degs, we will be able to lower ALAT to 0, restore transponder usage, and have some steady improvement over current conditions. By about November 15th, if all goes well, we should be back to ALON/ALAT = 0/0/, where we can stay for ~3 months. More details will follow in a few days.

Klla: Hkan SM7WSJ

Senaste info frn Oscar 40-teamet:

Because of the increasing ALON, it is now necessary to take pictures for attitude determination at the end of one orbit, and download them after apogee on the next orbit. This requires the IHU-2 to be left on through two passes of the radiation belts. Since EDAC is not currently active on the IHU-2, there is an excellent chance that it will crash about every second or third time this is done. A crash of the IHU-2 takes only a few minutes to correct, but until it is corrected the result will be an unmodulated tone on the middle beacon. If you should encounter this, be aware that the IHU-1 is running properly in the background and the command team will restore the beacon ASAP. The photos are not lost when the IHU-2 crashes, as long as the unit is not powered off.
The eclipses are continuing to lengthen and move later in the orbit. The timing of the beacon off interval will need frequent adjustment over the next several weeks. The interval will shortly be moved to MA 40 to 90.

–W4SM for the AO-40 Command Team

Klla: AMSAT-DL

AMSAT i USA har uppdaterat sin FAQ (frgor och svar) om Oscar 40. G in p deras hemsida och kolla.
http://www.amsat.org/amsat/sats/ao40/ao40-faq.html
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Klla: AMSAT-NA

Nytt schema frn den 16 juli.
Information frn AMSAT-UK enligt nedan:
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Effective this 765, on all days except Wednesday, the S2/K-Tx beacon only and passband segments are active again for testing. Note that the beacon only session (no passband) for S2 and K Tx s is MA 116-120, and the beacon + passband session is MA 120-128. As before, on Wednesday, the V-Rx along with L-band Rx s are connected to the passband from MA 120-128.

There s been some RUDAK issues too. Assi (I didn t know he was working on it) said:
The AO40 RUDAK team uploaded test code to one of the DSPs. This code generates a carrier at around 2401.625MHz ( doppler). The intent of this code is to help users do a ZR0 type experiment and test just how good their S-Band receive station is. The program generates a clean carrier at full RUDAK power, and then starts decreasing power in 3dB steps, all the way down to -30dB. One full cycle is 30 seconds. The resulting pattern is a sawtooth, and it is active between MA128 and MA160.

The code is new, and needs to be debugged. We would appreciate if some of you could record a wav file of the signal in SSB. If you can do so, please set your receiver so a clean tone is heard, and then record for at least 2 full minutes. During the recording don t update the frequency or mode so receiver phase modulation is not introduced. Once we get this code working, we will extend the period. If you can do this, please send Assi a zipped file emailed to 4x1kx@iarc.org

There were complaints about the amount of transmitter time RUDAK was taking; DB2OS commented:
The test code which Assi is working on is only a small part of things to come. This is to get a feeling about the I/Q modulator and performance of the DSP modems. And indeed it s a good test for you and other to test the system sensitivity, similar to the ZRO test in the good old days. The idea is to use the DSP modems for 1200 Bit/s BPSK PACSAT type operations, which would allow us to run RUDAK in parallel with the transponder passband.

Whatever will allow them to run the Passband and RUDAK downlink in parallel should be fine. 9600bps FM causes problems with distortion when the passband is on. 1200 Bit/s BPSK should be easy and if it works, they can look further ahead to other simultaneous digital modes.
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Se ven ANS 202.

Klla: ANS 202, AMSAT-UK

Den 27:e juni testades DSP-modulerna (RUDAK) ombord p AO-40 efter flera mnaders tystnad. 153k6-modulatorn testades och kunde hras p nerlnken. Ls mer p ANS 181.

Klla: ANS 181

Fljande DX-stationer kan hras p Osar 40 under juni/juli:

T88ZF from June 29-July 6, 2002
HB0 from July 13-14, 2002
TY, Benin from July 15-August 14, 2002
HK0ZZ from July 16-29, 2002
V63ZF from July 17-28, 2002.

Klla: ANS 173