Tag: Oscar 40

AO-40 is continuing to drift downward in ALON as predicted.

This is making the squint/range combination less favorable for passband use.

In addition, the solar angle is worsening and will shortly exceed 45 degs,limiting available power and warming the spacecraft considerably as the sun swings across the omni end of the spacecraft.

The AO-40 passbands will be turned off at MA=240 (23:50 UTC) on Saturday 4/19. They will remain off for about 4 weeks (or slightly less) until conditions improve.

– —W4SM for the AO-40 Command Team

Klla: amsat

Pictures taken today confirm that we have now reached ALON / ALAT = 51 / 20.

Magnetorquing has been turned off and we have begun
drifting down in ALON under the influence of the so-called mystery effect ( due to momentum wheel magnets interacting with earth s magnetic field ). Drift rate will
be approximately -18.2 degs / week at the current spin rate. This will place us on the other side of the sun in approximately 4 weeks, when we can decrease ALAT and begin chasing the sun back to 0/0.

The solar angles will begin increasing rapidly as we move backward and the passbands will be turned off within a few days until conditions improve. The beacon will remain on continuously.

– — W4SM for the AO-40 Command Team

Klla: amsat

AO-40 Update, 2003-04-07

ALON/ALAT is now 45/3 degs. We are beginning to raise ALAT to 20 degs. This will take about a week. Once we are at ALON/ALAT = 45/20 and have verified this position, we will turn off the passband and magnetorquer, and begin drifting past the sun, toward ALON/ALAT ~ 315/20.

Depending on final spin rate, the drift should take approximately a month. Once we reach this ALON, we will lower ALAT to 0 and passband will be restored, moved to the early portion of the orbit. We will then begin chasing the sun back to ALON/ALAT = 0/0.

W4SM for the AO-40 Command Team

Klla: amsat

Nytt schema 25 mars, annars ingen mera info frn AMSAT-DL eller AMSAT-UK.

Klla: AMSAT-DL

AMSAT News Service Bulletin 075.01 From AMSAT HQ
Silver Spring, MD. March 16, 2003
To All Radio Amateurs
BID: $ANS-075.01

AO-40 nominal ALON/ALAT is now 20 / 0. LON/ALAT will be slowly moved to 30/0 in the next week.

Given the worsening squints as we move ALON/ALAT, we have terminated the -Tx sessions until early summer when conditions improve.

Because of the poor squint angles early in the orbit the passband window ow starts at MA =80. It still ends at MA = 230 to allow time for battery harging before perigee eclipse.

The complete schedule is shown in the table below:

The command team also reminds all Users to maintain a clear area 25 kHz above and below the Middle Beacon.

S-band -> K Tx test conducted on Saturday, 15 March 2003, was a success. Report to follow from participants.

CORRECTION:
Several weeks ago, during the testing of the S1 receiver, It was indicated that the S2 receiver was connected to the 5-turn helix. This is not correct. Both S-band receivers are connected to the dish antenna. Only the S2 transmitter is connected to the 5-turn helix.

[ANS thanks Stacey, W4SM and Colin, VK5HI, for the above information]

Klla: ANS 075

Nyheter frn AMSAT-DL i Tyskland:

We are tentatively scheduling a second test of the S-Rx uplink to K-Tx downlink, tomorrow, 3/14, from MA 192 to 200. During this time, the S2 Tx will be OFF and downlink will be on K-band only, using S1 or S2 Rx uplink. Given the worsening squint, this will likely be the last test of this link until conditions improve in the early summer.
Please report your results to the amsat-bb.

Nyheter frn AMSAT-UK, England:

Because of the poor squint angles early in the orbit the passband window now starts at MA =80.It still ends at MA = 230 to allow time for battery charging before perigee eclipse.

Several weeks ago, during the testing of the S1 receiver, Stacey indicated that the S2 receiver was connected to the 5-turn helix. This is not correct. Both S-band receivers are connected to the dish antenna. Only the S2 transmitter is connected to the 5-turn helix. Sorry for the mix-up.

Klla: AMSAT-UK, AMSAT-DL